Bug Summary

File:clang/lib/Sema/SemaTemplateDeduction.cpp
Warning:line 3307, column 7
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name SemaTemplateDeduction.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -relaxed-aliasing -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/Sema -resource-dir /usr/lib/llvm-14/lib/clang/14.0.0 -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/Sema -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/lib/Sema -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/include -D NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-14/lib/clang/14.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/Sema -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e=. -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2021-09-04-040900-46481-1 -x c++ /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/lib/Sema/SemaTemplateDeduction.cpp
1//===- SemaTemplateDeduction.cpp - Template Argument Deduction ------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements C++ template argument deduction.
10//
11//===----------------------------------------------------------------------===//
12
13#include "clang/Sema/TemplateDeduction.h"
14#include "TreeTransform.h"
15#include "TypeLocBuilder.h"
16#include "clang/AST/ASTContext.h"
17#include "clang/AST/ASTLambda.h"
18#include "clang/AST/Decl.h"
19#include "clang/AST/DeclAccessPair.h"
20#include "clang/AST/DeclBase.h"
21#include "clang/AST/DeclCXX.h"
22#include "clang/AST/DeclTemplate.h"
23#include "clang/AST/DeclarationName.h"
24#include "clang/AST/Expr.h"
25#include "clang/AST/ExprCXX.h"
26#include "clang/AST/NestedNameSpecifier.h"
27#include "clang/AST/RecursiveASTVisitor.h"
28#include "clang/AST/TemplateBase.h"
29#include "clang/AST/TemplateName.h"
30#include "clang/AST/Type.h"
31#include "clang/AST/TypeLoc.h"
32#include "clang/AST/UnresolvedSet.h"
33#include "clang/Basic/AddressSpaces.h"
34#include "clang/Basic/ExceptionSpecificationType.h"
35#include "clang/Basic/LLVM.h"
36#include "clang/Basic/LangOptions.h"
37#include "clang/Basic/PartialDiagnostic.h"
38#include "clang/Basic/SourceLocation.h"
39#include "clang/Basic/Specifiers.h"
40#include "clang/Sema/Ownership.h"
41#include "clang/Sema/Sema.h"
42#include "clang/Sema/Template.h"
43#include "llvm/ADT/APInt.h"
44#include "llvm/ADT/APSInt.h"
45#include "llvm/ADT/ArrayRef.h"
46#include "llvm/ADT/DenseMap.h"
47#include "llvm/ADT/FoldingSet.h"
48#include "llvm/ADT/Optional.h"
49#include "llvm/ADT/SmallBitVector.h"
50#include "llvm/ADT/SmallPtrSet.h"
51#include "llvm/ADT/SmallVector.h"
52#include "llvm/Support/Casting.h"
53#include "llvm/Support/Compiler.h"
54#include "llvm/Support/ErrorHandling.h"
55#include <algorithm>
56#include <cassert>
57#include <tuple>
58#include <utility>
59
60namespace clang {
61
62 /// Various flags that control template argument deduction.
63 ///
64 /// These flags can be bitwise-OR'd together.
65 enum TemplateDeductionFlags {
66 /// No template argument deduction flags, which indicates the
67 /// strictest results for template argument deduction (as used for, e.g.,
68 /// matching class template partial specializations).
69 TDF_None = 0,
70
71 /// Within template argument deduction from a function call, we are
72 /// matching with a parameter type for which the original parameter was
73 /// a reference.
74 TDF_ParamWithReferenceType = 0x1,
75
76 /// Within template argument deduction from a function call, we
77 /// are matching in a case where we ignore cv-qualifiers.
78 TDF_IgnoreQualifiers = 0x02,
79
80 /// Within template argument deduction from a function call,
81 /// we are matching in a case where we can perform template argument
82 /// deduction from a template-id of a derived class of the argument type.
83 TDF_DerivedClass = 0x04,
84
85 /// Allow non-dependent types to differ, e.g., when performing
86 /// template argument deduction from a function call where conversions
87 /// may apply.
88 TDF_SkipNonDependent = 0x08,
89
90 /// Whether we are performing template argument deduction for
91 /// parameters and arguments in a top-level template argument
92 TDF_TopLevelParameterTypeList = 0x10,
93
94 /// Within template argument deduction from overload resolution per
95 /// C++ [over.over] allow matching function types that are compatible in
96 /// terms of noreturn and default calling convention adjustments, or
97 /// similarly matching a declared template specialization against a
98 /// possible template, per C++ [temp.deduct.decl]. In either case, permit
99 /// deduction where the parameter is a function type that can be converted
100 /// to the argument type.
101 TDF_AllowCompatibleFunctionType = 0x20,
102
103 /// Within template argument deduction for a conversion function, we are
104 /// matching with an argument type for which the original argument was
105 /// a reference.
106 TDF_ArgWithReferenceType = 0x40,
107 };
108}
109
110using namespace clang;
111using namespace sema;
112
113/// Compare two APSInts, extending and switching the sign as
114/// necessary to compare their values regardless of underlying type.
115static bool hasSameExtendedValue(llvm::APSInt X, llvm::APSInt Y) {
116 if (Y.getBitWidth() > X.getBitWidth())
117 X = X.extend(Y.getBitWidth());
118 else if (Y.getBitWidth() < X.getBitWidth())
119 Y = Y.extend(X.getBitWidth());
120
121 // If there is a signedness mismatch, correct it.
122 if (X.isSigned() != Y.isSigned()) {
123 // If the signed value is negative, then the values cannot be the same.
124 if ((Y.isSigned() && Y.isNegative()) || (X.isSigned() && X.isNegative()))
125 return false;
126
127 Y.setIsSigned(true);
128 X.setIsSigned(true);
129 }
130
131 return X == Y;
132}
133
134static Sema::TemplateDeductionResult
135DeduceTemplateArguments(Sema &S,
136 TemplateParameterList *TemplateParams,
137 const TemplateArgument &Param,
138 TemplateArgument Arg,
139 TemplateDeductionInfo &Info,
140 SmallVectorImpl<DeducedTemplateArgument> &Deduced);
141
142static Sema::TemplateDeductionResult
143DeduceTemplateArgumentsByTypeMatch(Sema &S,
144 TemplateParameterList *TemplateParams,
145 QualType Param,
146 QualType Arg,
147 TemplateDeductionInfo &Info,
148 SmallVectorImpl<DeducedTemplateArgument> &
149 Deduced,
150 unsigned TDF,
151 bool PartialOrdering = false,
152 bool DeducedFromArrayBound = false);
153
154static Sema::TemplateDeductionResult
155DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams,
156 ArrayRef<TemplateArgument> Params,
157 ArrayRef<TemplateArgument> Args,
158 TemplateDeductionInfo &Info,
159 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
160 bool NumberOfArgumentsMustMatch);
161
162static void MarkUsedTemplateParameters(ASTContext &Ctx,
163 const TemplateArgument &TemplateArg,
164 bool OnlyDeduced, unsigned Depth,
165 llvm::SmallBitVector &Used);
166
167static void MarkUsedTemplateParameters(ASTContext &Ctx, QualType T,
168 bool OnlyDeduced, unsigned Level,
169 llvm::SmallBitVector &Deduced);
170
171/// If the given expression is of a form that permits the deduction
172/// of a non-type template parameter, return the declaration of that
173/// non-type template parameter.
174static const NonTypeTemplateParmDecl *
175getDeducedParameterFromExpr(const Expr *E, unsigned Depth) {
176 // If we are within an alias template, the expression may have undergone
177 // any number of parameter substitutions already.
178 while (true) {
179 if (const auto *IC = dyn_cast<ImplicitCastExpr>(E))
180 E = IC->getSubExpr();
181 else if (const auto *CE = dyn_cast<ConstantExpr>(E))
182 E = CE->getSubExpr();
183 else if (const auto *Subst = dyn_cast<SubstNonTypeTemplateParmExpr>(E))
184 E = Subst->getReplacement();
185 else if (const auto *CCE = dyn_cast<CXXConstructExpr>(E)) {
186 // Look through implicit copy construction from an lvalue of the same type.
187 if (CCE->getParenOrBraceRange().isValid())
188 break;
189 // Note, there could be default arguments.
190 assert(CCE->getNumArgs() >= 1 && "implicit construct expr should have 1 arg")(static_cast<void> (0));
191 E = CCE->getArg(0);
192 } else
193 break;
194 }
195
196 if (const auto *DRE = dyn_cast<DeclRefExpr>(E))
197 if (const auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl()))
198 if (NTTP->getDepth() == Depth)
199 return NTTP;
200
201 return nullptr;
202}
203
204static const NonTypeTemplateParmDecl *
205getDeducedParameterFromExpr(TemplateDeductionInfo &Info, Expr *E) {
206 return getDeducedParameterFromExpr(E, Info.getDeducedDepth());
207}
208
209/// Determine whether two declaration pointers refer to the same
210/// declaration.
211static bool isSameDeclaration(Decl *X, Decl *Y) {
212 if (NamedDecl *NX = dyn_cast<NamedDecl>(X))
213 X = NX->getUnderlyingDecl();
214 if (NamedDecl *NY = dyn_cast<NamedDecl>(Y))
215 Y = NY->getUnderlyingDecl();
216
217 return X->getCanonicalDecl() == Y->getCanonicalDecl();
218}
219
220/// Verify that the given, deduced template arguments are compatible.
221///
222/// \returns The deduced template argument, or a NULL template argument if
223/// the deduced template arguments were incompatible.
224static DeducedTemplateArgument
225checkDeducedTemplateArguments(ASTContext &Context,
226 const DeducedTemplateArgument &X,
227 const DeducedTemplateArgument &Y) {
228 // We have no deduction for one or both of the arguments; they're compatible.
229 if (X.isNull())
230 return Y;
231 if (Y.isNull())
232 return X;
233
234 // If we have two non-type template argument values deduced for the same
235 // parameter, they must both match the type of the parameter, and thus must
236 // match each other's type. As we're only keeping one of them, we must check
237 // for that now. The exception is that if either was deduced from an array
238 // bound, the type is permitted to differ.
239 if (!X.wasDeducedFromArrayBound() && !Y.wasDeducedFromArrayBound()) {
240 QualType XType = X.getNonTypeTemplateArgumentType();
241 if (!XType.isNull()) {
242 QualType YType = Y.getNonTypeTemplateArgumentType();
243 if (YType.isNull() || !Context.hasSameType(XType, YType))
244 return DeducedTemplateArgument();
245 }
246 }
247
248 switch (X.getKind()) {
249 case TemplateArgument::Null:
250 llvm_unreachable("Non-deduced template arguments handled above")__builtin_unreachable();
251
252 case TemplateArgument::Type:
253 // If two template type arguments have the same type, they're compatible.
254 if (Y.getKind() == TemplateArgument::Type &&
255 Context.hasSameType(X.getAsType(), Y.getAsType()))
256 return X;
257
258 // If one of the two arguments was deduced from an array bound, the other
259 // supersedes it.
260 if (X.wasDeducedFromArrayBound() != Y.wasDeducedFromArrayBound())
261 return X.wasDeducedFromArrayBound() ? Y : X;
262
263 // The arguments are not compatible.
264 return DeducedTemplateArgument();
265
266 case TemplateArgument::Integral:
267 // If we deduced a constant in one case and either a dependent expression or
268 // declaration in another case, keep the integral constant.
269 // If both are integral constants with the same value, keep that value.
270 if (Y.getKind() == TemplateArgument::Expression ||
271 Y.getKind() == TemplateArgument::Declaration ||
272 (Y.getKind() == TemplateArgument::Integral &&
273 hasSameExtendedValue(X.getAsIntegral(), Y.getAsIntegral())))
274 return X.wasDeducedFromArrayBound() ? Y : X;
275
276 // All other combinations are incompatible.
277 return DeducedTemplateArgument();
278
279 case TemplateArgument::Template:
280 if (Y.getKind() == TemplateArgument::Template &&
281 Context.hasSameTemplateName(X.getAsTemplate(), Y.getAsTemplate()))
282 return X;
283
284 // All other combinations are incompatible.
285 return DeducedTemplateArgument();
286
287 case TemplateArgument::TemplateExpansion:
288 if (Y.getKind() == TemplateArgument::TemplateExpansion &&
289 Context.hasSameTemplateName(X.getAsTemplateOrTemplatePattern(),
290 Y.getAsTemplateOrTemplatePattern()))
291 return X;
292
293 // All other combinations are incompatible.
294 return DeducedTemplateArgument();
295
296 case TemplateArgument::Expression: {
297 if (Y.getKind() != TemplateArgument::Expression)
298 return checkDeducedTemplateArguments(Context, Y, X);
299
300 // Compare the expressions for equality
301 llvm::FoldingSetNodeID ID1, ID2;
302 X.getAsExpr()->Profile(ID1, Context, true);
303 Y.getAsExpr()->Profile(ID2, Context, true);
304 if (ID1 == ID2)
305 return X.wasDeducedFromArrayBound() ? Y : X;
306
307 // Differing dependent expressions are incompatible.
308 return DeducedTemplateArgument();
309 }
310
311 case TemplateArgument::Declaration:
312 assert(!X.wasDeducedFromArrayBound())(static_cast<void> (0));
313
314 // If we deduced a declaration and a dependent expression, keep the
315 // declaration.
316 if (Y.getKind() == TemplateArgument::Expression)
317 return X;
318
319 // If we deduced a declaration and an integral constant, keep the
320 // integral constant and whichever type did not come from an array
321 // bound.
322 if (Y.getKind() == TemplateArgument::Integral) {
323 if (Y.wasDeducedFromArrayBound())
324 return TemplateArgument(Context, Y.getAsIntegral(),
325 X.getParamTypeForDecl());
326 return Y;
327 }
328
329 // If we deduced two declarations, make sure that they refer to the
330 // same declaration.
331 if (Y.getKind() == TemplateArgument::Declaration &&
332 isSameDeclaration(X.getAsDecl(), Y.getAsDecl()))
333 return X;
334
335 // All other combinations are incompatible.
336 return DeducedTemplateArgument();
337
338 case TemplateArgument::NullPtr:
339 // If we deduced a null pointer and a dependent expression, keep the
340 // null pointer.
341 if (Y.getKind() == TemplateArgument::Expression)
342 return X;
343
344 // If we deduced a null pointer and an integral constant, keep the
345 // integral constant.
346 if (Y.getKind() == TemplateArgument::Integral)
347 return Y;
348
349 // If we deduced two null pointers, they are the same.
350 if (Y.getKind() == TemplateArgument::NullPtr)
351 return X;
352
353 // All other combinations are incompatible.
354 return DeducedTemplateArgument();
355
356 case TemplateArgument::Pack: {
357 if (Y.getKind() != TemplateArgument::Pack ||
358 X.pack_size() != Y.pack_size())
359 return DeducedTemplateArgument();
360
361 llvm::SmallVector<TemplateArgument, 8> NewPack;
362 for (TemplateArgument::pack_iterator XA = X.pack_begin(),
363 XAEnd = X.pack_end(),
364 YA = Y.pack_begin();
365 XA != XAEnd; ++XA, ++YA) {
366 TemplateArgument Merged = checkDeducedTemplateArguments(
367 Context, DeducedTemplateArgument(*XA, X.wasDeducedFromArrayBound()),
368 DeducedTemplateArgument(*YA, Y.wasDeducedFromArrayBound()));
369 if (Merged.isNull() && !(XA->isNull() && YA->isNull()))
370 return DeducedTemplateArgument();
371 NewPack.push_back(Merged);
372 }
373
374 return DeducedTemplateArgument(
375 TemplateArgument::CreatePackCopy(Context, NewPack),
376 X.wasDeducedFromArrayBound() && Y.wasDeducedFromArrayBound());
377 }
378 }
379
380 llvm_unreachable("Invalid TemplateArgument Kind!")__builtin_unreachable();
381}
382
383/// Deduce the value of the given non-type template parameter
384/// as the given deduced template argument. All non-type template parameter
385/// deduction is funneled through here.
386static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
387 Sema &S, TemplateParameterList *TemplateParams,
388 const NonTypeTemplateParmDecl *NTTP, const DeducedTemplateArgument &NewDeduced,
389 QualType ValueType, TemplateDeductionInfo &Info,
390 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
391 assert(NTTP->getDepth() == Info.getDeducedDepth() &&(static_cast<void> (0))
392 "deducing non-type template argument with wrong depth")(static_cast<void> (0));
393
394 DeducedTemplateArgument Result = checkDeducedTemplateArguments(
395 S.Context, Deduced[NTTP->getIndex()], NewDeduced);
396 if (Result.isNull()) {
397 Info.Param = const_cast<NonTypeTemplateParmDecl*>(NTTP);
398 Info.FirstArg = Deduced[NTTP->getIndex()];
399 Info.SecondArg = NewDeduced;
400 return Sema::TDK_Inconsistent;
401 }
402
403 Deduced[NTTP->getIndex()] = Result;
404 if (!S.getLangOpts().CPlusPlus17)
405 return Sema::TDK_Success;
406
407 if (NTTP->isExpandedParameterPack())
408 // FIXME: We may still need to deduce parts of the type here! But we
409 // don't have any way to find which slice of the type to use, and the
410 // type stored on the NTTP itself is nonsense. Perhaps the type of an
411 // expanded NTTP should be a pack expansion type?
412 return Sema::TDK_Success;
413
414 // Get the type of the parameter for deduction. If it's a (dependent) array
415 // or function type, we will not have decayed it yet, so do that now.
416 QualType ParamType = S.Context.getAdjustedParameterType(NTTP->getType());
417 if (auto *Expansion = dyn_cast<PackExpansionType>(ParamType))
418 ParamType = Expansion->getPattern();
419
420 // FIXME: It's not clear how deduction of a parameter of reference
421 // type from an argument (of non-reference type) should be performed.
422 // For now, we just remove reference types from both sides and let
423 // the final check for matching types sort out the mess.
424 ValueType = ValueType.getNonReferenceType();
425 if (ParamType->isReferenceType())
426 ParamType = ParamType.getNonReferenceType();
427 else
428 // Top-level cv-qualifiers are irrelevant for a non-reference type.
429 ValueType = ValueType.getUnqualifiedType();
430
431 return DeduceTemplateArgumentsByTypeMatch(
432 S, TemplateParams, ParamType, ValueType, Info, Deduced,
433 TDF_SkipNonDependent, /*PartialOrdering=*/false,
434 /*ArrayBound=*/NewDeduced.wasDeducedFromArrayBound());
435}
436
437/// Deduce the value of the given non-type template parameter
438/// from the given integral constant.
439static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
440 Sema &S, TemplateParameterList *TemplateParams,
441 const NonTypeTemplateParmDecl *NTTP, const llvm::APSInt &Value,
442 QualType ValueType, bool DeducedFromArrayBound, TemplateDeductionInfo &Info,
443 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
444 return DeduceNonTypeTemplateArgument(
445 S, TemplateParams, NTTP,
446 DeducedTemplateArgument(S.Context, Value, ValueType,
447 DeducedFromArrayBound),
448 ValueType, Info, Deduced);
449}
450
451/// Deduce the value of the given non-type template parameter
452/// from the given null pointer template argument type.
453static Sema::TemplateDeductionResult DeduceNullPtrTemplateArgument(
454 Sema &S, TemplateParameterList *TemplateParams,
455 const NonTypeTemplateParmDecl *NTTP, QualType NullPtrType,
456 TemplateDeductionInfo &Info,
457 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
458 Expr *Value = S.ImpCastExprToType(
459 new (S.Context) CXXNullPtrLiteralExpr(S.Context.NullPtrTy,
460 NTTP->getLocation()),
461 NullPtrType,
462 NullPtrType->isMemberPointerType() ? CK_NullToMemberPointer
463 : CK_NullToPointer)
464 .get();
465 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
466 DeducedTemplateArgument(Value),
467 Value->getType(), Info, Deduced);
468}
469
470/// Deduce the value of the given non-type template parameter
471/// from the given type- or value-dependent expression.
472///
473/// \returns true if deduction succeeded, false otherwise.
474static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
475 Sema &S, TemplateParameterList *TemplateParams,
476 const NonTypeTemplateParmDecl *NTTP, Expr *Value, TemplateDeductionInfo &Info,
477 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
478 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
479 DeducedTemplateArgument(Value),
480 Value->getType(), Info, Deduced);
481}
482
483/// Deduce the value of the given non-type template parameter
484/// from the given declaration.
485///
486/// \returns true if deduction succeeded, false otherwise.
487static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
488 Sema &S, TemplateParameterList *TemplateParams,
489 const NonTypeTemplateParmDecl *NTTP, ValueDecl *D, QualType T,
490 TemplateDeductionInfo &Info,
491 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
492 D = D ? cast<ValueDecl>(D->getCanonicalDecl()) : nullptr;
493 TemplateArgument New(D, T);
494 return DeduceNonTypeTemplateArgument(
495 S, TemplateParams, NTTP, DeducedTemplateArgument(New), T, Info, Deduced);
496}
497
498static Sema::TemplateDeductionResult
499DeduceTemplateArguments(Sema &S,
500 TemplateParameterList *TemplateParams,
501 TemplateName Param,
502 TemplateName Arg,
503 TemplateDeductionInfo &Info,
504 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
505 TemplateDecl *ParamDecl = Param.getAsTemplateDecl();
506 if (!ParamDecl) {
507 // The parameter type is dependent and is not a template template parameter,
508 // so there is nothing that we can deduce.
509 return Sema::TDK_Success;
510 }
511
512 if (TemplateTemplateParmDecl *TempParam
513 = dyn_cast<TemplateTemplateParmDecl>(ParamDecl)) {
514 // If we're not deducing at this depth, there's nothing to deduce.
515 if (TempParam->getDepth() != Info.getDeducedDepth())
516 return Sema::TDK_Success;
517
518 DeducedTemplateArgument NewDeduced(S.Context.getCanonicalTemplateName(Arg));
519 DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context,
520 Deduced[TempParam->getIndex()],
521 NewDeduced);
522 if (Result.isNull()) {
523 Info.Param = TempParam;
524 Info.FirstArg = Deduced[TempParam->getIndex()];
525 Info.SecondArg = NewDeduced;
526 return Sema::TDK_Inconsistent;
527 }
528
529 Deduced[TempParam->getIndex()] = Result;
530 return Sema::TDK_Success;
531 }
532
533 // Verify that the two template names are equivalent.
534 if (S.Context.hasSameTemplateName(Param, Arg))
535 return Sema::TDK_Success;
536
537 // Mismatch of non-dependent template parameter to argument.
538 Info.FirstArg = TemplateArgument(Param);
539 Info.SecondArg = TemplateArgument(Arg);
540 return Sema::TDK_NonDeducedMismatch;
541}
542
543/// Deduce the template arguments by comparing the template parameter
544/// type (which is a template-id) with the template argument type.
545///
546/// \param S the Sema
547///
548/// \param TemplateParams the template parameters that we are deducing
549///
550/// \param Param the parameter type
551///
552/// \param Arg the argument type
553///
554/// \param Info information about the template argument deduction itself
555///
556/// \param Deduced the deduced template arguments
557///
558/// \returns the result of template argument deduction so far. Note that a
559/// "success" result means that template argument deduction has not yet failed,
560/// but it may still fail, later, for other reasons.
561static Sema::TemplateDeductionResult
562DeduceTemplateArguments(Sema &S,
563 TemplateParameterList *TemplateParams,
564 const TemplateSpecializationType *Param,
565 QualType Arg,
566 TemplateDeductionInfo &Info,
567 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
568 assert(Arg.isCanonical() && "Argument type must be canonical")(static_cast<void> (0));
569
570 // Treat an injected-class-name as its underlying template-id.
571 if (auto *Injected = dyn_cast<InjectedClassNameType>(Arg))
572 Arg = Injected->getInjectedSpecializationType();
573
574 // Check whether the template argument is a dependent template-id.
575 if (const TemplateSpecializationType *SpecArg
576 = dyn_cast<TemplateSpecializationType>(Arg)) {
577 // Perform template argument deduction for the template name.
578 if (Sema::TemplateDeductionResult Result
579 = DeduceTemplateArguments(S, TemplateParams,
580 Param->getTemplateName(),
581 SpecArg->getTemplateName(),
582 Info, Deduced))
583 return Result;
584
585
586 // Perform template argument deduction on each template
587 // argument. Ignore any missing/extra arguments, since they could be
588 // filled in by default arguments.
589 return DeduceTemplateArguments(S, TemplateParams,
590 Param->template_arguments(),
591 SpecArg->template_arguments(), Info, Deduced,
592 /*NumberOfArgumentsMustMatch=*/false);
593 }
594
595 // If the argument type is a class template specialization, we
596 // perform template argument deduction using its template
597 // arguments.
598 const RecordType *RecordArg = dyn_cast<RecordType>(Arg);
599 if (!RecordArg) {
600 Info.FirstArg = TemplateArgument(QualType(Param, 0));
601 Info.SecondArg = TemplateArgument(Arg);
602 return Sema::TDK_NonDeducedMismatch;
603 }
604
605 ClassTemplateSpecializationDecl *SpecArg
606 = dyn_cast<ClassTemplateSpecializationDecl>(RecordArg->getDecl());
607 if (!SpecArg) {
608 Info.FirstArg = TemplateArgument(QualType(Param, 0));
609 Info.SecondArg = TemplateArgument(Arg);
610 return Sema::TDK_NonDeducedMismatch;
611 }
612
613 // Perform template argument deduction for the template name.
614 if (Sema::TemplateDeductionResult Result
615 = DeduceTemplateArguments(S,
616 TemplateParams,
617 Param->getTemplateName(),
618 TemplateName(SpecArg->getSpecializedTemplate()),
619 Info, Deduced))
620 return Result;
621
622 // Perform template argument deduction for the template arguments.
623 return DeduceTemplateArguments(S, TemplateParams, Param->template_arguments(),
624 SpecArg->getTemplateArgs().asArray(), Info,
625 Deduced, /*NumberOfArgumentsMustMatch=*/true);
626}
627
628/// Determines whether the given type is an opaque type that
629/// might be more qualified when instantiated.
630static bool IsPossiblyOpaquelyQualifiedType(QualType T) {
631 switch (T->getTypeClass()) {
632 case Type::TypeOfExpr:
633 case Type::TypeOf:
634 case Type::DependentName:
635 case Type::Decltype:
636 case Type::UnresolvedUsing:
637 case Type::TemplateTypeParm:
638 return true;
639
640 case Type::ConstantArray:
641 case Type::IncompleteArray:
642 case Type::VariableArray:
643 case Type::DependentSizedArray:
644 return IsPossiblyOpaquelyQualifiedType(
645 cast<ArrayType>(T)->getElementType());
646
647 default:
648 return false;
649 }
650}
651
652/// Helper function to build a TemplateParameter when we don't
653/// know its type statically.
654static TemplateParameter makeTemplateParameter(Decl *D) {
655 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(D))
656 return TemplateParameter(TTP);
657 if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D))
658 return TemplateParameter(NTTP);
659
660 return TemplateParameter(cast<TemplateTemplateParmDecl>(D));
661}
662
663/// A pack that we're currently deducing.
664struct clang::DeducedPack {
665 // The index of the pack.
666 unsigned Index;
667
668 // The old value of the pack before we started deducing it.
669 DeducedTemplateArgument Saved;
670
671 // A deferred value of this pack from an inner deduction, that couldn't be
672 // deduced because this deduction hadn't happened yet.
673 DeducedTemplateArgument DeferredDeduction;
674
675 // The new value of the pack.
676 SmallVector<DeducedTemplateArgument, 4> New;
677
678 // The outer deduction for this pack, if any.
679 DeducedPack *Outer = nullptr;
680
681 DeducedPack(unsigned Index) : Index(Index) {}
682};
683
684namespace {
685
686/// A scope in which we're performing pack deduction.
687class PackDeductionScope {
688public:
689 /// Prepare to deduce the packs named within Pattern.
690 PackDeductionScope(Sema &S, TemplateParameterList *TemplateParams,
691 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
692 TemplateDeductionInfo &Info, TemplateArgument Pattern)
693 : S(S), TemplateParams(TemplateParams), Deduced(Deduced), Info(Info) {
694 unsigned NumNamedPacks = addPacks(Pattern);
695 finishConstruction(NumNamedPacks);
696 }
697
698 /// Prepare to directly deduce arguments of the parameter with index \p Index.
699 PackDeductionScope(Sema &S, TemplateParameterList *TemplateParams,
700 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
701 TemplateDeductionInfo &Info, unsigned Index)
702 : S(S), TemplateParams(TemplateParams), Deduced(Deduced), Info(Info) {
703 addPack(Index);
704 finishConstruction(1);
705 }
706
707private:
708 void addPack(unsigned Index) {
709 // Save the deduced template argument for the parameter pack expanded
710 // by this pack expansion, then clear out the deduction.
711 DeducedPack Pack(Index);
712 Pack.Saved = Deduced[Index];
713 Deduced[Index] = TemplateArgument();
714
715 // FIXME: What if we encounter multiple packs with different numbers of
716 // pre-expanded expansions? (This should already have been diagnosed
717 // during substitution.)
718 if (Optional<unsigned> ExpandedPackExpansions =
719 getExpandedPackSize(TemplateParams->getParam(Index)))
720 FixedNumExpansions = ExpandedPackExpansions;
721
722 Packs.push_back(Pack);
723 }
724
725 unsigned addPacks(TemplateArgument Pattern) {
726 // Compute the set of template parameter indices that correspond to
727 // parameter packs expanded by the pack expansion.
728 llvm::SmallBitVector SawIndices(TemplateParams->size());
729 llvm::SmallVector<TemplateArgument, 4> ExtraDeductions;
730
731 auto AddPack = [&](unsigned Index) {
732 if (SawIndices[Index])
733 return;
734 SawIndices[Index] = true;
735 addPack(Index);
736
737 // Deducing a parameter pack that is a pack expansion also constrains the
738 // packs appearing in that parameter to have the same deduced arity. Also,
739 // in C++17 onwards, deducing a non-type template parameter deduces its
740 // type, so we need to collect the pending deduced values for those packs.
741 if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(
742 TemplateParams->getParam(Index))) {
743 if (!NTTP->isExpandedParameterPack())
744 if (auto *Expansion = dyn_cast<PackExpansionType>(NTTP->getType()))
745 ExtraDeductions.push_back(Expansion->getPattern());
746 }
747 // FIXME: Also collect the unexpanded packs in any type and template
748 // parameter packs that are pack expansions.
749 };
750
751 auto Collect = [&](TemplateArgument Pattern) {
752 SmallVector<UnexpandedParameterPack, 2> Unexpanded;
753 S.collectUnexpandedParameterPacks(Pattern, Unexpanded);
754 for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) {
755 unsigned Depth, Index;
756 std::tie(Depth, Index) = getDepthAndIndex(Unexpanded[I]);
757 if (Depth == Info.getDeducedDepth())
758 AddPack(Index);
759 }
760 };
761
762 // Look for unexpanded packs in the pattern.
763 Collect(Pattern);
764 assert(!Packs.empty() && "Pack expansion without unexpanded packs?")(static_cast<void> (0));
765
766 unsigned NumNamedPacks = Packs.size();
767
768 // Also look for unexpanded packs that are indirectly deduced by deducing
769 // the sizes of the packs in this pattern.
770 while (!ExtraDeductions.empty())
771 Collect(ExtraDeductions.pop_back_val());
772
773 return NumNamedPacks;
774 }
775
776 void finishConstruction(unsigned NumNamedPacks) {
777 // Dig out the partially-substituted pack, if there is one.
778 const TemplateArgument *PartialPackArgs = nullptr;
779 unsigned NumPartialPackArgs = 0;
780 std::pair<unsigned, unsigned> PartialPackDepthIndex(-1u, -1u);
781 if (auto *Scope = S.CurrentInstantiationScope)
782 if (auto *Partial = Scope->getPartiallySubstitutedPack(
783 &PartialPackArgs, &NumPartialPackArgs))
784 PartialPackDepthIndex = getDepthAndIndex(Partial);
785
786 // This pack expansion will have been partially or fully expanded if
787 // it only names explicitly-specified parameter packs (including the
788 // partially-substituted one, if any).
789 bool IsExpanded = true;
790 for (unsigned I = 0; I != NumNamedPacks; ++I) {
791 if (Packs[I].Index >= Info.getNumExplicitArgs()) {
792 IsExpanded = false;
793 IsPartiallyExpanded = false;
794 break;
795 }
796 if (PartialPackDepthIndex ==
797 std::make_pair(Info.getDeducedDepth(), Packs[I].Index)) {
798 IsPartiallyExpanded = true;
799 }
800 }
801
802 // Skip over the pack elements that were expanded into separate arguments.
803 // If we partially expanded, this is the number of partial arguments.
804 if (IsPartiallyExpanded)
805 PackElements += NumPartialPackArgs;
806 else if (IsExpanded)
807 PackElements += *FixedNumExpansions;
808
809 for (auto &Pack : Packs) {
810 if (Info.PendingDeducedPacks.size() > Pack.Index)
811 Pack.Outer = Info.PendingDeducedPacks[Pack.Index];
812 else
813 Info.PendingDeducedPacks.resize(Pack.Index + 1);
814 Info.PendingDeducedPacks[Pack.Index] = &Pack;
815
816 if (PartialPackDepthIndex ==
817 std::make_pair(Info.getDeducedDepth(), Pack.Index)) {
818 Pack.New.append(PartialPackArgs, PartialPackArgs + NumPartialPackArgs);
819 // We pre-populate the deduced value of the partially-substituted
820 // pack with the specified value. This is not entirely correct: the
821 // value is supposed to have been substituted, not deduced, but the
822 // cases where this is observable require an exact type match anyway.
823 //
824 // FIXME: If we could represent a "depth i, index j, pack elem k"
825 // parameter, we could substitute the partially-substituted pack
826 // everywhere and avoid this.
827 if (!IsPartiallyExpanded)
828 Deduced[Pack.Index] = Pack.New[PackElements];
829 }
830 }
831 }
832
833public:
834 ~PackDeductionScope() {
835 for (auto &Pack : Packs)
836 Info.PendingDeducedPacks[Pack.Index] = Pack.Outer;
837 }
838
839 /// Determine whether this pack has already been partially expanded into a
840 /// sequence of (prior) function parameters / template arguments.
841 bool isPartiallyExpanded() { return IsPartiallyExpanded; }
842
843 /// Determine whether this pack expansion scope has a known, fixed arity.
844 /// This happens if it involves a pack from an outer template that has
845 /// (notionally) already been expanded.
846 bool hasFixedArity() { return FixedNumExpansions.hasValue(); }
847
848 /// Determine whether the next element of the argument is still part of this
849 /// pack. This is the case unless the pack is already expanded to a fixed
850 /// length.
851 bool hasNextElement() {
852 return !FixedNumExpansions || *FixedNumExpansions > PackElements;
853 }
854
855 /// Move to deducing the next element in each pack that is being deduced.
856 void nextPackElement() {
857 // Capture the deduced template arguments for each parameter pack expanded
858 // by this pack expansion, add them to the list of arguments we've deduced
859 // for that pack, then clear out the deduced argument.
860 for (auto &Pack : Packs) {
861 DeducedTemplateArgument &DeducedArg = Deduced[Pack.Index];
862 if (!Pack.New.empty() || !DeducedArg.isNull()) {
863 while (Pack.New.size() < PackElements)
864 Pack.New.push_back(DeducedTemplateArgument());
865 if (Pack.New.size() == PackElements)
866 Pack.New.push_back(DeducedArg);
867 else
868 Pack.New[PackElements] = DeducedArg;
869 DeducedArg = Pack.New.size() > PackElements + 1
870 ? Pack.New[PackElements + 1]
871 : DeducedTemplateArgument();
872 }
873 }
874 ++PackElements;
875 }
876
877 /// Finish template argument deduction for a set of argument packs,
878 /// producing the argument packs and checking for consistency with prior
879 /// deductions.
880 Sema::TemplateDeductionResult finish() {
881 // Build argument packs for each of the parameter packs expanded by this
882 // pack expansion.
883 for (auto &Pack : Packs) {
884 // Put back the old value for this pack.
885 Deduced[Pack.Index] = Pack.Saved;
886
887 // Always make sure the size of this pack is correct, even if we didn't
888 // deduce any values for it.
889 //
890 // FIXME: This isn't required by the normative wording, but substitution
891 // and post-substitution checking will always fail if the arity of any
892 // pack is not equal to the number of elements we processed. (Either that
893 // or something else has gone *very* wrong.) We're permitted to skip any
894 // hard errors from those follow-on steps by the intent (but not the
895 // wording) of C++ [temp.inst]p8:
896 //
897 // If the function selected by overload resolution can be determined
898 // without instantiating a class template definition, it is unspecified
899 // whether that instantiation actually takes place
900 Pack.New.resize(PackElements);
901
902 // Build or find a new value for this pack.
903 DeducedTemplateArgument NewPack;
904 if (Pack.New.empty()) {
905 // If we deduced an empty argument pack, create it now.
906 NewPack = DeducedTemplateArgument(TemplateArgument::getEmptyPack());
907 } else {
908 TemplateArgument *ArgumentPack =
909 new (S.Context) TemplateArgument[Pack.New.size()];
910 std::copy(Pack.New.begin(), Pack.New.end(), ArgumentPack);
911 NewPack = DeducedTemplateArgument(
912 TemplateArgument(llvm::makeArrayRef(ArgumentPack, Pack.New.size())),
913 // FIXME: This is wrong, it's possible that some pack elements are
914 // deduced from an array bound and others are not:
915 // template<typename ...T, T ...V> void g(const T (&...p)[V]);
916 // g({1, 2, 3}, {{}, {}});
917 // ... should deduce T = {int, size_t (from array bound)}.
918 Pack.New[0].wasDeducedFromArrayBound());
919 }
920
921 // Pick where we're going to put the merged pack.
922 DeducedTemplateArgument *Loc;
923 if (Pack.Outer) {
924 if (Pack.Outer->DeferredDeduction.isNull()) {
925 // Defer checking this pack until we have a complete pack to compare
926 // it against.
927 Pack.Outer->DeferredDeduction = NewPack;
928 continue;
929 }
930 Loc = &Pack.Outer->DeferredDeduction;
931 } else {
932 Loc = &Deduced[Pack.Index];
933 }
934
935 // Check the new pack matches any previous value.
936 DeducedTemplateArgument OldPack = *Loc;
937 DeducedTemplateArgument Result =
938 checkDeducedTemplateArguments(S.Context, OldPack, NewPack);
939
940 // If we deferred a deduction of this pack, check that one now too.
941 if (!Result.isNull() && !Pack.DeferredDeduction.isNull()) {
942 OldPack = Result;
943 NewPack = Pack.DeferredDeduction;
944 Result = checkDeducedTemplateArguments(S.Context, OldPack, NewPack);
945 }
946
947 NamedDecl *Param = TemplateParams->getParam(Pack.Index);
948 if (Result.isNull()) {
949 Info.Param = makeTemplateParameter(Param);
950 Info.FirstArg = OldPack;
951 Info.SecondArg = NewPack;
952 return Sema::TDK_Inconsistent;
953 }
954
955 // If we have a pre-expanded pack and we didn't deduce enough elements
956 // for it, fail deduction.
957 if (Optional<unsigned> Expansions = getExpandedPackSize(Param)) {
958 if (*Expansions != PackElements) {
959 Info.Param = makeTemplateParameter(Param);
960 Info.FirstArg = Result;
961 return Sema::TDK_IncompletePack;
962 }
963 }
964
965 *Loc = Result;
966 }
967
968 return Sema::TDK_Success;
969 }
970
971private:
972 Sema &S;
973 TemplateParameterList *TemplateParams;
974 SmallVectorImpl<DeducedTemplateArgument> &Deduced;
975 TemplateDeductionInfo &Info;
976 unsigned PackElements = 0;
977 bool IsPartiallyExpanded = false;
978 /// The number of expansions, if we have a fully-expanded pack in this scope.
979 Optional<unsigned> FixedNumExpansions;
980
981 SmallVector<DeducedPack, 2> Packs;
982};
983
984} // namespace
985
986/// Deduce the template arguments by comparing the list of parameter
987/// types to the list of argument types, as in the parameter-type-lists of
988/// function types (C++ [temp.deduct.type]p10).
989///
990/// \param S The semantic analysis object within which we are deducing
991///
992/// \param TemplateParams The template parameters that we are deducing
993///
994/// \param Params The list of parameter types
995///
996/// \param NumParams The number of types in \c Params
997///
998/// \param Args The list of argument types
999///
1000/// \param NumArgs The number of types in \c Args
1001///
1002/// \param Info information about the template argument deduction itself
1003///
1004/// \param Deduced the deduced template arguments
1005///
1006/// \param TDF bitwise OR of the TemplateDeductionFlags bits that describe
1007/// how template argument deduction is performed.
1008///
1009/// \param PartialOrdering If true, we are performing template argument
1010/// deduction for during partial ordering for a call
1011/// (C++0x [temp.deduct.partial]).
1012///
1013/// \returns the result of template argument deduction so far. Note that a
1014/// "success" result means that template argument deduction has not yet failed,
1015/// but it may still fail, later, for other reasons.
1016static Sema::TemplateDeductionResult
1017DeduceTemplateArguments(Sema &S,
1018 TemplateParameterList *TemplateParams,
1019 const QualType *Params, unsigned NumParams,
1020 const QualType *Args, unsigned NumArgs,
1021 TemplateDeductionInfo &Info,
1022 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
1023 unsigned TDF,
1024 bool PartialOrdering = false) {
1025 // C++0x [temp.deduct.type]p10:
1026 // Similarly, if P has a form that contains (T), then each parameter type
1027 // Pi of the respective parameter-type- list of P is compared with the
1028 // corresponding parameter type Ai of the corresponding parameter-type-list
1029 // of A. [...]
1030 unsigned ArgIdx = 0, ParamIdx = 0;
1031 for (; ParamIdx != NumParams; ++ParamIdx) {
1032 // Check argument types.
1033 const PackExpansionType *Expansion
1034 = dyn_cast<PackExpansionType>(Params[ParamIdx]);
1035 if (!Expansion) {
1036 // Simple case: compare the parameter and argument types at this point.
1037
1038 // Make sure we have an argument.
1039 if (ArgIdx >= NumArgs)
1040 return Sema::TDK_MiscellaneousDeductionFailure;
1041
1042 if (isa<PackExpansionType>(Args[ArgIdx])) {
1043 // C++0x [temp.deduct.type]p22:
1044 // If the original function parameter associated with A is a function
1045 // parameter pack and the function parameter associated with P is not
1046 // a function parameter pack, then template argument deduction fails.
1047 return Sema::TDK_MiscellaneousDeductionFailure;
1048 }
1049
1050 if (Sema::TemplateDeductionResult Result
1051 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1052 Params[ParamIdx], Args[ArgIdx],
1053 Info, Deduced, TDF,
1054 PartialOrdering))
1055 return Result;
1056
1057 ++ArgIdx;
1058 continue;
1059 }
1060
1061 // C++0x [temp.deduct.type]p10:
1062 // If the parameter-declaration corresponding to Pi is a function
1063 // parameter pack, then the type of its declarator- id is compared with
1064 // each remaining parameter type in the parameter-type-list of A. Each
1065 // comparison deduces template arguments for subsequent positions in the
1066 // template parameter packs expanded by the function parameter pack.
1067
1068 QualType Pattern = Expansion->getPattern();
1069 PackDeductionScope PackScope(S, TemplateParams, Deduced, Info, Pattern);
1070
1071 // A pack scope with fixed arity is not really a pack any more, so is not
1072 // a non-deduced context.
1073 if (ParamIdx + 1 == NumParams || PackScope.hasFixedArity()) {
1074 for (; ArgIdx < NumArgs && PackScope.hasNextElement(); ++ArgIdx) {
1075 // Deduce template arguments from the pattern.
1076 if (Sema::TemplateDeductionResult Result
1077 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, Pattern,
1078 Args[ArgIdx], Info, Deduced,
1079 TDF, PartialOrdering))
1080 return Result;
1081
1082 PackScope.nextPackElement();
1083 }
1084 } else {
1085 // C++0x [temp.deduct.type]p5:
1086 // The non-deduced contexts are:
1087 // - A function parameter pack that does not occur at the end of the
1088 // parameter-declaration-clause.
1089 //
1090 // FIXME: There is no wording to say what we should do in this case. We
1091 // choose to resolve this by applying the same rule that is applied for a
1092 // function call: that is, deduce all contained packs to their
1093 // explicitly-specified values (or to <> if there is no such value).
1094 //
1095 // This is seemingly-arbitrarily different from the case of a template-id
1096 // with a non-trailing pack-expansion in its arguments, which renders the
1097 // entire template-argument-list a non-deduced context.
1098
1099 // If the parameter type contains an explicitly-specified pack that we
1100 // could not expand, skip the number of parameters notionally created
1101 // by the expansion.
1102 Optional<unsigned> NumExpansions = Expansion->getNumExpansions();
1103 if (NumExpansions && !PackScope.isPartiallyExpanded()) {
1104 for (unsigned I = 0; I != *NumExpansions && ArgIdx < NumArgs;
1105 ++I, ++ArgIdx)
1106 PackScope.nextPackElement();
1107 }
1108 }
1109
1110 // Build argument packs for each of the parameter packs expanded by this
1111 // pack expansion.
1112 if (auto Result = PackScope.finish())
1113 return Result;
1114 }
1115
1116 // Make sure we don't have any extra arguments.
1117 if (ArgIdx < NumArgs)
1118 return Sema::TDK_MiscellaneousDeductionFailure;
1119
1120 return Sema::TDK_Success;
1121}
1122
1123/// Determine whether the parameter has qualifiers that the argument
1124/// lacks. Put another way, determine whether there is no way to add
1125/// a deduced set of qualifiers to the ParamType that would result in
1126/// its qualifiers matching those of the ArgType.
1127static bool hasInconsistentOrSupersetQualifiersOf(QualType ParamType,
1128 QualType ArgType) {
1129 Qualifiers ParamQs = ParamType.getQualifiers();
1130 Qualifiers ArgQs = ArgType.getQualifiers();
1131
1132 if (ParamQs == ArgQs)
1133 return false;
1134
1135 // Mismatched (but not missing) Objective-C GC attributes.
1136 if (ParamQs.getObjCGCAttr() != ArgQs.getObjCGCAttr() &&
1137 ParamQs.hasObjCGCAttr())
1138 return true;
1139
1140 // Mismatched (but not missing) address spaces.
1141 if (ParamQs.getAddressSpace() != ArgQs.getAddressSpace() &&
1142 ParamQs.hasAddressSpace())
1143 return true;
1144
1145 // Mismatched (but not missing) Objective-C lifetime qualifiers.
1146 if (ParamQs.getObjCLifetime() != ArgQs.getObjCLifetime() &&
1147 ParamQs.hasObjCLifetime())
1148 return true;
1149
1150 // CVR qualifiers inconsistent or a superset.
1151 return (ParamQs.getCVRQualifiers() & ~ArgQs.getCVRQualifiers()) != 0;
1152}
1153
1154/// Compare types for equality with respect to possibly compatible
1155/// function types (noreturn adjustment, implicit calling conventions). If any
1156/// of parameter and argument is not a function, just perform type comparison.
1157///
1158/// \param Param the template parameter type.
1159///
1160/// \param Arg the argument type.
1161bool Sema::isSameOrCompatibleFunctionType(CanQualType Param,
1162 CanQualType Arg) {
1163 const FunctionType *ParamFunction = Param->getAs<FunctionType>(),
1164 *ArgFunction = Arg->getAs<FunctionType>();
1165
1166 // Just compare if not functions.
1167 if (!ParamFunction || !ArgFunction)
1168 return Param == Arg;
1169
1170 // Noreturn and noexcept adjustment.
1171 QualType AdjustedParam;
1172 if (IsFunctionConversion(Param, Arg, AdjustedParam))
1173 return Arg == Context.getCanonicalType(AdjustedParam);
1174
1175 // FIXME: Compatible calling conventions.
1176
1177 return Param == Arg;
1178}
1179
1180/// Get the index of the first template parameter that was originally from the
1181/// innermost template-parameter-list. This is 0 except when we concatenate
1182/// the template parameter lists of a class template and a constructor template
1183/// when forming an implicit deduction guide.
1184static unsigned getFirstInnerIndex(FunctionTemplateDecl *FTD) {
1185 auto *Guide = dyn_cast<CXXDeductionGuideDecl>(FTD->getTemplatedDecl());
1186 if (!Guide || !Guide->isImplicit())
1187 return 0;
1188 return Guide->getDeducedTemplate()->getTemplateParameters()->size();
1189}
1190
1191/// Determine whether a type denotes a forwarding reference.
1192static bool isForwardingReference(QualType Param, unsigned FirstInnerIndex) {
1193 // C++1z [temp.deduct.call]p3:
1194 // A forwarding reference is an rvalue reference to a cv-unqualified
1195 // template parameter that does not represent a template parameter of a
1196 // class template.
1197 if (auto *ParamRef = Param->getAs<RValueReferenceType>()) {
1198 if (ParamRef->getPointeeType().getQualifiers())
1199 return false;
1200 auto *TypeParm = ParamRef->getPointeeType()->getAs<TemplateTypeParmType>();
1201 return TypeParm && TypeParm->getIndex() >= FirstInnerIndex;
1202 }
1203 return false;
1204}
1205
1206/// Attempt to deduce the template arguments by checking the base types
1207/// according to (C++20 [temp.deduct.call] p4b3.
1208///
1209/// \param S the semantic analysis object within which we are deducing.
1210///
1211/// \param RecordT the top level record object we are deducing against.
1212///
1213/// \param TemplateParams the template parameters that we are deducing.
1214///
1215/// \param SpecParam the template specialization parameter type.
1216///
1217/// \param Info information about the template argument deduction itself.
1218///
1219/// \param Deduced the deduced template arguments.
1220///
1221/// \returns the result of template argument deduction with the bases. "invalid"
1222/// means no matches, "success" found a single item, and the
1223/// "MiscellaneousDeductionFailure" result happens when the match is ambiguous.
1224static Sema::TemplateDeductionResult DeduceTemplateBases(
1225 Sema &S, const RecordType *RecordT, TemplateParameterList *TemplateParams,
1226 const TemplateSpecializationType *SpecParam, TemplateDeductionInfo &Info,
1227 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
1228 // C++14 [temp.deduct.call] p4b3:
1229 // If P is a class and P has the form simple-template-id, then the
1230 // transformed A can be a derived class of the deduced A. Likewise if
1231 // P is a pointer to a class of the form simple-template-id, the
1232 // transformed A can be a pointer to a derived class pointed to by the
1233 // deduced A. However, if there is a class C that is a (direct or
1234 // indirect) base class of D and derived (directly or indirectly) from a
1235 // class B and that would be a valid deduced A, the deduced A cannot be
1236 // B or pointer to B, respectively.
1237 //
1238 // These alternatives are considered only if type deduction would
1239 // otherwise fail. If they yield more than one possible deduced A, the
1240 // type deduction fails.
1241
1242 // Use a breadth-first search through the bases to collect the set of
1243 // successful matches. Visited contains the set of nodes we have already
1244 // visited, while ToVisit is our stack of records that we still need to
1245 // visit. Matches contains a list of matches that have yet to be
1246 // disqualified.
1247 llvm::SmallPtrSet<const RecordType *, 8> Visited;
1248 SmallVector<const RecordType *, 8> ToVisit;
1249 // We iterate over this later, so we have to use MapVector to ensure
1250 // determinism.
1251 llvm::MapVector<const RecordType *, SmallVector<DeducedTemplateArgument, 8>>
1252 Matches;
1253
1254 auto AddBases = [&Visited, &ToVisit](const RecordType *RT) {
1255 CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1256 for (const auto &Base : RD->bases()) {
1257 assert(Base.getType()->isRecordType() &&(static_cast<void> (0))
1258 "Base class that isn't a record?")(static_cast<void> (0));
1259 const RecordType *RT = Base.getType()->getAs<RecordType>();
1260 if (Visited.insert(RT).second)
1261 ToVisit.push_back(Base.getType()->getAs<RecordType>());
1262 }
1263 };
1264
1265 // Set up the loop by adding all the bases.
1266 AddBases(RecordT);
1267
1268 // Search each path of bases until we either run into a successful match
1269 // (where all bases of it are invalid), or we run out of bases.
1270 while (!ToVisit.empty()) {
1271 const RecordType *NextT = ToVisit.pop_back_val();
1272
1273 SmallVector<DeducedTemplateArgument, 8> DeducedCopy(Deduced.begin(),
1274 Deduced.end());
1275 TemplateDeductionInfo BaseInfo(TemplateDeductionInfo::ForBase, Info);
1276 Sema::TemplateDeductionResult BaseResult =
1277 DeduceTemplateArguments(S, TemplateParams, SpecParam,
1278 QualType(NextT, 0), BaseInfo, DeducedCopy);
1279
1280 // If this was a successful deduction, add it to the list of matches,
1281 // otherwise we need to continue searching its bases.
1282 if (BaseResult == Sema::TDK_Success)
1283 Matches.insert({NextT, DeducedCopy});
1284 else
1285 AddBases(NextT);
1286 }
1287
1288 // At this point, 'Matches' contains a list of seemingly valid bases, however
1289 // in the event that we have more than 1 match, it is possible that the base
1290 // of one of the matches might be disqualified for being a base of another
1291 // valid match. We can count on cyclical instantiations being invalid to
1292 // simplify the disqualifications. That is, if A & B are both matches, and B
1293 // inherits from A (disqualifying A), we know that A cannot inherit from B.
1294 if (Matches.size() > 1) {
1295 Visited.clear();
1296 for (const auto &Match : Matches)
1297 AddBases(Match.first);
1298
1299 // We can give up once we have a single item (or have run out of things to
1300 // search) since cyclical inheritence isn't valid.
1301 while (Matches.size() > 1 && !ToVisit.empty()) {
1302 const RecordType *NextT = ToVisit.pop_back_val();
1303 Matches.erase(NextT);
1304
1305 // Always add all bases, since the inheritence tree can contain
1306 // disqualifications for multiple matches.
1307 AddBases(NextT);
1308 }
1309 }
1310
1311 if (Matches.empty())
1312 return Sema::TDK_Invalid;
1313 if (Matches.size() > 1)
1314 return Sema::TDK_MiscellaneousDeductionFailure;
1315
1316 std::swap(Matches.front().second, Deduced);
1317 return Sema::TDK_Success;
1318}
1319
1320/// Deduce the template arguments by comparing the parameter type and
1321/// the argument type (C++ [temp.deduct.type]).
1322///
1323/// \param S the semantic analysis object within which we are deducing
1324///
1325/// \param TemplateParams the template parameters that we are deducing
1326///
1327/// \param ParamIn the parameter type
1328///
1329/// \param ArgIn the argument type
1330///
1331/// \param Info information about the template argument deduction itself
1332///
1333/// \param Deduced the deduced template arguments
1334///
1335/// \param TDF bitwise OR of the TemplateDeductionFlags bits that describe
1336/// how template argument deduction is performed.
1337///
1338/// \param PartialOrdering Whether we're performing template argument deduction
1339/// in the context of partial ordering (C++0x [temp.deduct.partial]).
1340///
1341/// \returns the result of template argument deduction so far. Note that a
1342/// "success" result means that template argument deduction has not yet failed,
1343/// but it may still fail, later, for other reasons.
1344static Sema::TemplateDeductionResult
1345DeduceTemplateArgumentsByTypeMatch(Sema &S,
1346 TemplateParameterList *TemplateParams,
1347 QualType ParamIn, QualType ArgIn,
1348 TemplateDeductionInfo &Info,
1349 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
1350 unsigned TDF,
1351 bool PartialOrdering,
1352 bool DeducedFromArrayBound) {
1353 // We only want to look at the canonical types, since typedefs and
1354 // sugar are not part of template argument deduction.
1355 QualType Param = S.Context.getCanonicalType(ParamIn);
1356 QualType Arg = S.Context.getCanonicalType(ArgIn);
1357
1358 // If the argument type is a pack expansion, look at its pattern.
1359 // This isn't explicitly called out
1360 if (const PackExpansionType *ArgExpansion
1361 = dyn_cast<PackExpansionType>(Arg))
1362 Arg = ArgExpansion->getPattern();
1363
1364 if (PartialOrdering) {
1365 // C++11 [temp.deduct.partial]p5:
1366 // Before the partial ordering is done, certain transformations are
1367 // performed on the types used for partial ordering:
1368 // - If P is a reference type, P is replaced by the type referred to.
1369 const ReferenceType *ParamRef = Param->getAs<ReferenceType>();
1370 if (ParamRef)
1371 Param = ParamRef->getPointeeType();
1372
1373 // - If A is a reference type, A is replaced by the type referred to.
1374 const ReferenceType *ArgRef = Arg->getAs<ReferenceType>();
1375 if (ArgRef)
1376 Arg = ArgRef->getPointeeType();
1377
1378 if (ParamRef && ArgRef && S.Context.hasSameUnqualifiedType(Param, Arg)) {
1379 // C++11 [temp.deduct.partial]p9:
1380 // If, for a given type, deduction succeeds in both directions (i.e.,
1381 // the types are identical after the transformations above) and both
1382 // P and A were reference types [...]:
1383 // - if [one type] was an lvalue reference and [the other type] was
1384 // not, [the other type] is not considered to be at least as
1385 // specialized as [the first type]
1386 // - if [one type] is more cv-qualified than [the other type],
1387 // [the other type] is not considered to be at least as specialized
1388 // as [the first type]
1389 // Objective-C ARC adds:
1390 // - [one type] has non-trivial lifetime, [the other type] has
1391 // __unsafe_unretained lifetime, and the types are otherwise
1392 // identical
1393 //
1394 // A is "considered to be at least as specialized" as P iff deduction
1395 // succeeds, so we model this as a deduction failure. Note that
1396 // [the first type] is P and [the other type] is A here; the standard
1397 // gets this backwards.
1398 Qualifiers ParamQuals = Param.getQualifiers();
1399 Qualifiers ArgQuals = Arg.getQualifiers();
1400 if ((ParamRef->isLValueReferenceType() &&
1401 !ArgRef->isLValueReferenceType()) ||
1402 ParamQuals.isStrictSupersetOf(ArgQuals) ||
1403 (ParamQuals.hasNonTrivialObjCLifetime() &&
1404 ArgQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone &&
1405 ParamQuals.withoutObjCLifetime() ==
1406 ArgQuals.withoutObjCLifetime())) {
1407 Info.FirstArg = TemplateArgument(ParamIn);
1408 Info.SecondArg = TemplateArgument(ArgIn);
1409 return Sema::TDK_NonDeducedMismatch;
1410 }
1411 }
1412
1413 // C++11 [temp.deduct.partial]p7:
1414 // Remove any top-level cv-qualifiers:
1415 // - If P is a cv-qualified type, P is replaced by the cv-unqualified
1416 // version of P.
1417 Param = Param.getUnqualifiedType();
1418 // - If A is a cv-qualified type, A is replaced by the cv-unqualified
1419 // version of A.
1420 Arg = Arg.getUnqualifiedType();
1421 } else {
1422 // C++0x [temp.deduct.call]p4 bullet 1:
1423 // - If the original P is a reference type, the deduced A (i.e., the type
1424 // referred to by the reference) can be more cv-qualified than the
1425 // transformed A.
1426 if (TDF & TDF_ParamWithReferenceType) {
1427 Qualifiers Quals;
1428 QualType UnqualParam = S.Context.getUnqualifiedArrayType(Param, Quals);
1429 Quals.setCVRQualifiers(Quals.getCVRQualifiers() &
1430 Arg.getCVRQualifiers());
1431 Param = S.Context.getQualifiedType(UnqualParam, Quals);
1432 }
1433
1434 if ((TDF & TDF_TopLevelParameterTypeList) && !Param->isFunctionType()) {
1435 // C++0x [temp.deduct.type]p10:
1436 // If P and A are function types that originated from deduction when
1437 // taking the address of a function template (14.8.2.2) or when deducing
1438 // template arguments from a function declaration (14.8.2.6) and Pi and
1439 // Ai are parameters of the top-level parameter-type-list of P and A,
1440 // respectively, Pi is adjusted if it is a forwarding reference and Ai
1441 // is an lvalue reference, in
1442 // which case the type of Pi is changed to be the template parameter
1443 // type (i.e., T&& is changed to simply T). [ Note: As a result, when
1444 // Pi is T&& and Ai is X&, the adjusted Pi will be T, causing T to be
1445 // deduced as X&. - end note ]
1446 TDF &= ~TDF_TopLevelParameterTypeList;
1447 if (isForwardingReference(Param, 0) && Arg->isLValueReferenceType())
1448 Param = Param->getPointeeType();
1449 }
1450 }
1451
1452 // C++ [temp.deduct.type]p9:
1453 // A template type argument T, a template template argument TT or a
1454 // template non-type argument i can be deduced if P and A have one of
1455 // the following forms:
1456 //
1457 // T
1458 // cv-list T
1459 if (const TemplateTypeParmType *TemplateTypeParm
1460 = Param->getAs<TemplateTypeParmType>()) {
1461 // Just skip any attempts to deduce from a placeholder type or a parameter
1462 // at a different depth.
1463 if (Arg->isPlaceholderType() ||
1464 Info.getDeducedDepth() != TemplateTypeParm->getDepth())
1465 return Sema::TDK_Success;
1466
1467 unsigned Index = TemplateTypeParm->getIndex();
1468 bool RecanonicalizeArg = false;
1469
1470 // If the argument type is an array type, move the qualifiers up to the
1471 // top level, so they can be matched with the qualifiers on the parameter.
1472 if (isa<ArrayType>(Arg)) {
1473 Qualifiers Quals;
1474 Arg = S.Context.getUnqualifiedArrayType(Arg, Quals);
1475 if (Quals) {
1476 Arg = S.Context.getQualifiedType(Arg, Quals);
1477 RecanonicalizeArg = true;
1478 }
1479 }
1480
1481 // The argument type can not be less qualified than the parameter
1482 // type.
1483 if (!(TDF & TDF_IgnoreQualifiers) &&
1484 hasInconsistentOrSupersetQualifiersOf(Param, Arg)) {
1485 Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index));
1486 Info.FirstArg = TemplateArgument(Param);
1487 Info.SecondArg = TemplateArgument(Arg);
1488 return Sema::TDK_Underqualified;
1489 }
1490
1491 // Do not match a function type with a cv-qualified type.
1492 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1584
1493 if (Arg->isFunctionType() && Param.hasQualifiers()) {
1494 return Sema::TDK_NonDeducedMismatch;
1495 }
1496
1497 assert(TemplateTypeParm->getDepth() == Info.getDeducedDepth() &&(static_cast<void> (0))
1498 "saw template type parameter with wrong depth")(static_cast<void> (0));
1499 assert(Arg != S.Context.OverloadTy && "Unresolved overloaded function")(static_cast<void> (0));
1500 QualType DeducedType = Arg;
1501
1502 // Remove any qualifiers on the parameter from the deduced type.
1503 // We checked the qualifiers for consistency above.
1504 Qualifiers DeducedQs = DeducedType.getQualifiers();
1505 Qualifiers ParamQs = Param.getQualifiers();
1506 DeducedQs.removeCVRQualifiers(ParamQs.getCVRQualifiers());
1507 if (ParamQs.hasObjCGCAttr())
1508 DeducedQs.removeObjCGCAttr();
1509 if (ParamQs.hasAddressSpace())
1510 DeducedQs.removeAddressSpace();
1511 if (ParamQs.hasObjCLifetime())
1512 DeducedQs.removeObjCLifetime();
1513
1514 // Objective-C ARC:
1515 // If template deduction would produce a lifetime qualifier on a type
1516 // that is not a lifetime type, template argument deduction fails.
1517 if (ParamQs.hasObjCLifetime() && !DeducedType->isObjCLifetimeType() &&
1518 !DeducedType->isDependentType()) {
1519 Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index));
1520 Info.FirstArg = TemplateArgument(Param);
1521 Info.SecondArg = TemplateArgument(Arg);
1522 return Sema::TDK_Underqualified;
1523 }
1524
1525 // Objective-C ARC:
1526 // If template deduction would produce an argument type with lifetime type
1527 // but no lifetime qualifier, the __strong lifetime qualifier is inferred.
1528 if (S.getLangOpts().ObjCAutoRefCount &&
1529 DeducedType->isObjCLifetimeType() &&
1530 !DeducedQs.hasObjCLifetime())
1531 DeducedQs.setObjCLifetime(Qualifiers::OCL_Strong);
1532
1533 DeducedType = S.Context.getQualifiedType(DeducedType.getUnqualifiedType(),
1534 DeducedQs);
1535
1536 if (RecanonicalizeArg)
1537 DeducedType = S.Context.getCanonicalType(DeducedType);
1538
1539 DeducedTemplateArgument NewDeduced(DeducedType, DeducedFromArrayBound);
1540 DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context,
1541 Deduced[Index],
1542 NewDeduced);
1543 if (Result.isNull()) {
1544 Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index));
1545 Info.FirstArg = Deduced[Index];
1546 Info.SecondArg = NewDeduced;
1547 return Sema::TDK_Inconsistent;
1548 }
1549
1550 Deduced[Index] = Result;
1551 return Sema::TDK_Success;
1552 }
1553
1554 // Set up the template argument deduction information for a failure.
1555 Info.FirstArg = TemplateArgument(ParamIn);
1556 Info.SecondArg = TemplateArgument(ArgIn);
1557
1558 // If the parameter is an already-substituted template parameter
1559 // pack, do nothing: we don't know which of its arguments to look
1560 // at, so we have to wait until all of the parameter packs in this
1561 // expansion have arguments.
1562 if (isa<SubstTemplateTypeParmPackType>(Param))
1563 return Sema::TDK_Success;
1564
1565 // Check the cv-qualifiers on the parameter and argument types.
1566 CanQualType CanParam = S.Context.getCanonicalType(Param);
1567 CanQualType CanArg = S.Context.getCanonicalType(Arg);
1568 if (!(TDF & TDF_IgnoreQualifiers)) {
1569 if (TDF & TDF_ParamWithReferenceType) {
1570 if (hasInconsistentOrSupersetQualifiersOf(Param, Arg))
1571 return Sema::TDK_NonDeducedMismatch;
1572 } else if (TDF & TDF_ArgWithReferenceType) {
1573 // C++ [temp.deduct.conv]p4:
1574 // If the original A is a reference type, A can be more cv-qualified
1575 // than the deduced A
1576 if (!Arg.getQualifiers().compatiblyIncludes(Param.getQualifiers()))
1577 return Sema::TDK_NonDeducedMismatch;
1578
1579 // Strip out all extra qualifiers from the argument to figure out the
1580 // type we're converting to, prior to the qualification conversion.
1581 Qualifiers Quals;
1582 Arg = S.Context.getUnqualifiedArrayType(Arg, Quals);
1583 Arg = S.Context.getQualifiedType(Arg, Param.getQualifiers());
1584 } else if (!IsPossiblyOpaquelyQualifiedType(Param)) {
1585 if (Param.getCVRQualifiers() != Arg.getCVRQualifiers())
1586 return Sema::TDK_NonDeducedMismatch;
1587 }
1588
1589 // If the parameter type is not dependent, there is nothing to deduce.
1590 if (!Param->isDependentType()) {
1591 if (!(TDF & TDF_SkipNonDependent)) {
1592 bool NonDeduced =
1593 (TDF & TDF_AllowCompatibleFunctionType)
1594 ? !S.isSameOrCompatibleFunctionType(CanParam, CanArg)
1595 : Param != Arg;
1596 if (NonDeduced) {
1597 return Sema::TDK_NonDeducedMismatch;
1598 }
1599 }
1600 return Sema::TDK_Success;
1601 }
1602 } else if (!Param->isDependentType()) {
1603 if (!(TDF & TDF_SkipNonDependent)) {
1604 CanQualType ParamUnqualType = CanParam.getUnqualifiedType(),
1605 ArgUnqualType = CanArg.getUnqualifiedType();
1606 bool Success =
1607 (TDF & TDF_AllowCompatibleFunctionType)
1608 ? S.isSameOrCompatibleFunctionType(ParamUnqualType, ArgUnqualType)
1609 : ParamUnqualType == ArgUnqualType;
1610 if (Success)
1611 return Sema::TDK_Success;
1612 } else {
1613 return Sema::TDK_Success;
1614 }
1615 }
1616
1617 switch (Param->getTypeClass()) {
1618 // Non-canonical types cannot appear here.
1619#define NON_CANONICAL_TYPE(Class, Base) \
1620 case Type::Class: llvm_unreachable("deducing non-canonical type: " #Class)__builtin_unreachable();
1621#define TYPE(Class, Base)
1622#include "clang/AST/TypeNodes.inc"
1623
1624 case Type::TemplateTypeParm:
1625 case Type::SubstTemplateTypeParmPack:
1626 llvm_unreachable("Type nodes handled above")__builtin_unreachable();
1627
1628 // These types cannot be dependent, so simply check whether the types are
1629 // the same.
1630 case Type::Builtin:
1631 case Type::VariableArray:
1632 case Type::Vector:
1633 case Type::FunctionNoProto:
1634 case Type::Record:
1635 case Type::Enum:
1636 case Type::ObjCObject:
1637 case Type::ObjCInterface:
1638 case Type::ObjCObjectPointer:
1639 case Type::ExtInt:
1640 if (TDF & TDF_SkipNonDependent)
1641 return Sema::TDK_Success;
1642
1643 if (TDF & TDF_IgnoreQualifiers) {
1644 Param = Param.getUnqualifiedType();
1645 Arg = Arg.getUnqualifiedType();
1646 }
1647
1648 return Param == Arg? Sema::TDK_Success : Sema::TDK_NonDeducedMismatch;
1649
1650 // _Complex T [placeholder extension]
1651 case Type::Complex:
1652 if (const ComplexType *ComplexArg = Arg->getAs<ComplexType>())
1653 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1654 cast<ComplexType>(Param)->getElementType(),
1655 ComplexArg->getElementType(),
1656 Info, Deduced, TDF);
1657
1658 return Sema::TDK_NonDeducedMismatch;
1659
1660 // _Atomic T [extension]
1661 case Type::Atomic:
1662 if (const AtomicType *AtomicArg = Arg->getAs<AtomicType>())
1663 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1664 cast<AtomicType>(Param)->getValueType(),
1665 AtomicArg->getValueType(),
1666 Info, Deduced, TDF);
1667
1668 return Sema::TDK_NonDeducedMismatch;
1669
1670 // T *
1671 case Type::Pointer: {
1672 QualType PointeeType;
1673 if (const PointerType *PointerArg = Arg->getAs<PointerType>()) {
1674 PointeeType = PointerArg->getPointeeType();
1675 } else if (const ObjCObjectPointerType *PointerArg
1676 = Arg->getAs<ObjCObjectPointerType>()) {
1677 PointeeType = PointerArg->getPointeeType();
1678 } else {
1679 return Sema::TDK_NonDeducedMismatch;
1680 }
1681
1682 unsigned SubTDF = TDF & (TDF_IgnoreQualifiers | TDF_DerivedClass);
1683 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1684 cast<PointerType>(Param)->getPointeeType(),
1685 PointeeType,
1686 Info, Deduced, SubTDF);
1687 }
1688
1689 // T &
1690 case Type::LValueReference: {
1691 const LValueReferenceType *ReferenceArg =
1692 Arg->getAs<LValueReferenceType>();
1693 if (!ReferenceArg)
1694 return Sema::TDK_NonDeducedMismatch;
1695
1696 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1697 cast<LValueReferenceType>(Param)->getPointeeType(),
1698 ReferenceArg->getPointeeType(), Info, Deduced, 0);
1699 }
1700
1701 // T && [C++0x]
1702 case Type::RValueReference: {
1703 const RValueReferenceType *ReferenceArg =
1704 Arg->getAs<RValueReferenceType>();
1705 if (!ReferenceArg)
1706 return Sema::TDK_NonDeducedMismatch;
1707
1708 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1709 cast<RValueReferenceType>(Param)->getPointeeType(),
1710 ReferenceArg->getPointeeType(),
1711 Info, Deduced, 0);
1712 }
1713
1714 // T [] (implied, but not stated explicitly)
1715 case Type::IncompleteArray: {
1716 const IncompleteArrayType *IncompleteArrayArg =
1717 S.Context.getAsIncompleteArrayType(Arg);
1718 if (!IncompleteArrayArg)
1719 return Sema::TDK_NonDeducedMismatch;
1720
1721 unsigned SubTDF = TDF & TDF_IgnoreQualifiers;
1722 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1723 S.Context.getAsIncompleteArrayType(Param)->getElementType(),
1724 IncompleteArrayArg->getElementType(),
1725 Info, Deduced, SubTDF);
1726 }
1727
1728 // T [integer-constant]
1729 case Type::ConstantArray: {
1730 const ConstantArrayType *ConstantArrayArg =
1731 S.Context.getAsConstantArrayType(Arg);
1732 if (!ConstantArrayArg)
1733 return Sema::TDK_NonDeducedMismatch;
1734
1735 const ConstantArrayType *ConstantArrayParm =
1736 S.Context.getAsConstantArrayType(Param);
1737 if (ConstantArrayArg->getSize() != ConstantArrayParm->getSize())
1738 return Sema::TDK_NonDeducedMismatch;
1739
1740 unsigned SubTDF = TDF & TDF_IgnoreQualifiers;
1741 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1742 ConstantArrayParm->getElementType(),
1743 ConstantArrayArg->getElementType(),
1744 Info, Deduced, SubTDF);
1745 }
1746
1747 // type [i]
1748 case Type::DependentSizedArray: {
1749 const ArrayType *ArrayArg = S.Context.getAsArrayType(Arg);
1750 if (!ArrayArg)
1751 return Sema::TDK_NonDeducedMismatch;
1752
1753 unsigned SubTDF = TDF & TDF_IgnoreQualifiers;
1754
1755 // Check the element type of the arrays
1756 const DependentSizedArrayType *DependentArrayParm
1757 = S.Context.getAsDependentSizedArrayType(Param);
1758 if (Sema::TemplateDeductionResult Result
1759 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1760 DependentArrayParm->getElementType(),
1761 ArrayArg->getElementType(),
1762 Info, Deduced, SubTDF))
1763 return Result;
1764
1765 // Determine the array bound is something we can deduce.
1766 const NonTypeTemplateParmDecl *NTTP
1767 = getDeducedParameterFromExpr(Info, DependentArrayParm->getSizeExpr());
1768 if (!NTTP)
1769 return Sema::TDK_Success;
1770
1771 // We can perform template argument deduction for the given non-type
1772 // template parameter.
1773 assert(NTTP->getDepth() == Info.getDeducedDepth() &&(static_cast<void> (0))
1774 "saw non-type template parameter with wrong depth")(static_cast<void> (0));
1775 if (const ConstantArrayType *ConstantArrayArg
1776 = dyn_cast<ConstantArrayType>(ArrayArg)) {
1777 llvm::APSInt Size(ConstantArrayArg->getSize());
1778 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, Size,
1779 S.Context.getSizeType(),
1780 /*ArrayBound=*/true,
1781 Info, Deduced);
1782 }
1783 if (const DependentSizedArrayType *DependentArrayArg
1784 = dyn_cast<DependentSizedArrayType>(ArrayArg))
1785 if (DependentArrayArg->getSizeExpr())
1786 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
1787 DependentArrayArg->getSizeExpr(),
1788 Info, Deduced);
1789
1790 // Incomplete type does not match a dependently-sized array type
1791 return Sema::TDK_NonDeducedMismatch;
1792 }
1793
1794 // type(*)(T)
1795 // T(*)()
1796 // T(*)(T)
1797 case Type::FunctionProto: {
1798 unsigned SubTDF = TDF & TDF_TopLevelParameterTypeList;
1799 const FunctionProtoType *FunctionProtoArg =
1800 dyn_cast<FunctionProtoType>(Arg);
1801 if (!FunctionProtoArg)
1802 return Sema::TDK_NonDeducedMismatch;
1803
1804 const FunctionProtoType *FunctionProtoParam =
1805 cast<FunctionProtoType>(Param);
1806
1807 if (FunctionProtoParam->getMethodQuals()
1808 != FunctionProtoArg->getMethodQuals() ||
1809 FunctionProtoParam->getRefQualifier()
1810 != FunctionProtoArg->getRefQualifier() ||
1811 FunctionProtoParam->isVariadic() != FunctionProtoArg->isVariadic())
1812 return Sema::TDK_NonDeducedMismatch;
1813
1814 // Check return types.
1815 if (auto Result = DeduceTemplateArgumentsByTypeMatch(
1816 S, TemplateParams, FunctionProtoParam->getReturnType(),
1817 FunctionProtoArg->getReturnType(), Info, Deduced, 0))
1818 return Result;
1819
1820 // Check parameter types.
1821 if (auto Result = DeduceTemplateArguments(
1822 S, TemplateParams, FunctionProtoParam->param_type_begin(),
1823 FunctionProtoParam->getNumParams(),
1824 FunctionProtoArg->param_type_begin(),
1825 FunctionProtoArg->getNumParams(), Info, Deduced, SubTDF))
1826 return Result;
1827
1828 if (TDF & TDF_AllowCompatibleFunctionType)
1829 return Sema::TDK_Success;
1830
1831 // FIXME: Per core-2016/10/1019 (no corresponding core issue yet), permit
1832 // deducing through the noexcept-specifier if it's part of the canonical
1833 // type. libstdc++ relies on this.
1834 Expr *NoexceptExpr = FunctionProtoParam->getNoexceptExpr();
1835 if (const NonTypeTemplateParmDecl *NTTP =
1836 NoexceptExpr ? getDeducedParameterFromExpr(Info, NoexceptExpr)
1837 : nullptr) {
1838 assert(NTTP->getDepth() == Info.getDeducedDepth() &&(static_cast<void> (0))
1839 "saw non-type template parameter with wrong depth")(static_cast<void> (0));
1840
1841 llvm::APSInt Noexcept(1);
1842 switch (FunctionProtoArg->canThrow()) {
1843 case CT_Cannot:
1844 Noexcept = 1;
1845 LLVM_FALLTHROUGH[[gnu::fallthrough]];
1846
1847 case CT_Can:
1848 // We give E in noexcept(E) the "deduced from array bound" treatment.
1849 // FIXME: Should we?
1850 return DeduceNonTypeTemplateArgument(
1851 S, TemplateParams, NTTP, Noexcept, S.Context.BoolTy,
1852 /*ArrayBound*/true, Info, Deduced);
1853
1854 case CT_Dependent:
1855 if (Expr *ArgNoexceptExpr = FunctionProtoArg->getNoexceptExpr())
1856 return DeduceNonTypeTemplateArgument(
1857 S, TemplateParams, NTTP, ArgNoexceptExpr, Info, Deduced);
1858 // Can't deduce anything from throw(T...).
1859 break;
1860 }
1861 }
1862 // FIXME: Detect non-deduced exception specification mismatches?
1863 //
1864 // Careful about [temp.deduct.call] and [temp.deduct.conv], which allow
1865 // top-level differences in noexcept-specifications.
1866
1867 return Sema::TDK_Success;
1868 }
1869
1870 case Type::InjectedClassName:
1871 // Treat a template's injected-class-name as if the template
1872 // specialization type had been used.
1873 Param = cast<InjectedClassNameType>(Param)
1874 ->getInjectedSpecializationType();
1875 assert(isa<TemplateSpecializationType>(Param) &&(static_cast<void> (0))
1876 "injected class name is not a template specialization type")(static_cast<void> (0));
1877 LLVM_FALLTHROUGH[[gnu::fallthrough]];
1878
1879 // template-name<T> (where template-name refers to a class template)
1880 // template-name<i>
1881 // TT<T>
1882 // TT<i>
1883 // TT<>
1884 case Type::TemplateSpecialization: {
1885 const TemplateSpecializationType *SpecParam =
1886 cast<TemplateSpecializationType>(Param);
1887
1888 // When Arg cannot be a derived class, we can just try to deduce template
1889 // arguments from the template-id.
1890 const RecordType *RecordT = Arg->getAs<RecordType>();
1891 if (!(TDF & TDF_DerivedClass) || !RecordT)
1892 return DeduceTemplateArguments(S, TemplateParams, SpecParam, Arg, Info,
1893 Deduced);
1894
1895 SmallVector<DeducedTemplateArgument, 8> DeducedOrig(Deduced.begin(),
1896 Deduced.end());
1897
1898 Sema::TemplateDeductionResult Result = DeduceTemplateArguments(
1899 S, TemplateParams, SpecParam, Arg, Info, Deduced);
1900
1901 if (Result == Sema::TDK_Success)
1902 return Result;
1903
1904 // We cannot inspect base classes as part of deduction when the type
1905 // is incomplete, so either instantiate any templates necessary to
1906 // complete the type, or skip over it if it cannot be completed.
1907 if (!S.isCompleteType(Info.getLocation(), Arg))
1908 return Result;
1909
1910 // Reset the incorrectly deduced argument from above.
1911 Deduced = DeducedOrig;
1912
1913 // Check bases according to C++14 [temp.deduct.call] p4b3:
1914 Sema::TemplateDeductionResult BaseResult = DeduceTemplateBases(
1915 S, RecordT, TemplateParams, SpecParam, Info, Deduced);
1916
1917 if (BaseResult != Sema::TDK_Invalid)
1918 return BaseResult;
1919 return Result;
1920 }
1921
1922 // T type::*
1923 // T T::*
1924 // T (type::*)()
1925 // type (T::*)()
1926 // type (type::*)(T)
1927 // type (T::*)(T)
1928 // T (type::*)(T)
1929 // T (T::*)()
1930 // T (T::*)(T)
1931 case Type::MemberPointer: {
1932 const MemberPointerType *MemPtrParam = cast<MemberPointerType>(Param);
1933 const MemberPointerType *MemPtrArg = dyn_cast<MemberPointerType>(Arg);
1934 if (!MemPtrArg)
1935 return Sema::TDK_NonDeducedMismatch;
1936
1937 QualType ParamPointeeType = MemPtrParam->getPointeeType();
1938 if (ParamPointeeType->isFunctionType())
1939 S.adjustMemberFunctionCC(ParamPointeeType, /*IsStatic=*/true,
1940 /*IsCtorOrDtor=*/false, Info.getLocation());
1941 QualType ArgPointeeType = MemPtrArg->getPointeeType();
1942 if (ArgPointeeType->isFunctionType())
1943 S.adjustMemberFunctionCC(ArgPointeeType, /*IsStatic=*/true,
1944 /*IsCtorOrDtor=*/false, Info.getLocation());
1945
1946 if (Sema::TemplateDeductionResult Result
1947 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1948 ParamPointeeType,
1949 ArgPointeeType,
1950 Info, Deduced,
1951 TDF & TDF_IgnoreQualifiers))
1952 return Result;
1953
1954 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1955 QualType(MemPtrParam->getClass(), 0),
1956 QualType(MemPtrArg->getClass(), 0),
1957 Info, Deduced,
1958 TDF & TDF_IgnoreQualifiers);
1959 }
1960
1961 // (clang extension)
1962 //
1963 // type(^)(T)
1964 // T(^)()
1965 // T(^)(T)
1966 case Type::BlockPointer: {
1967 const BlockPointerType *BlockPtrParam = cast<BlockPointerType>(Param);
1968 const BlockPointerType *BlockPtrArg = dyn_cast<BlockPointerType>(Arg);
1969
1970 if (!BlockPtrArg)
1971 return Sema::TDK_NonDeducedMismatch;
1972
1973 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1974 BlockPtrParam->getPointeeType(),
1975 BlockPtrArg->getPointeeType(),
1976 Info, Deduced, 0);
1977 }
1978
1979 // (clang extension)
1980 //
1981 // T __attribute__(((ext_vector_type(<integral constant>))))
1982 case Type::ExtVector: {
1983 const ExtVectorType *VectorParam = cast<ExtVectorType>(Param);
1984 if (const ExtVectorType *VectorArg = dyn_cast<ExtVectorType>(Arg)) {
1985 // Make sure that the vectors have the same number of elements.
1986 if (VectorParam->getNumElements() != VectorArg->getNumElements())
1987 return Sema::TDK_NonDeducedMismatch;
1988
1989 // Perform deduction on the element types.
1990 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1991 VectorParam->getElementType(),
1992 VectorArg->getElementType(),
1993 Info, Deduced, TDF);
1994 }
1995
1996 if (const DependentSizedExtVectorType *VectorArg
1997 = dyn_cast<DependentSizedExtVectorType>(Arg)) {
1998 // We can't check the number of elements, since the argument has a
1999 // dependent number of elements. This can only occur during partial
2000 // ordering.
2001
2002 // Perform deduction on the element types.
2003 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
2004 VectorParam->getElementType(),
2005 VectorArg->getElementType(),
2006 Info, Deduced, TDF);
2007 }
2008
2009 return Sema::TDK_NonDeducedMismatch;
2010 }
2011
2012 case Type::DependentVector: {
2013 const auto *VectorParam = cast<DependentVectorType>(Param);
2014
2015 if (const auto *VectorArg = dyn_cast<VectorType>(Arg)) {
2016 // Perform deduction on the element types.
2017 if (Sema::TemplateDeductionResult Result =
2018 DeduceTemplateArgumentsByTypeMatch(
2019 S, TemplateParams, VectorParam->getElementType(),
2020 VectorArg->getElementType(), Info, Deduced, TDF))
2021 return Result;
2022
2023 // Perform deduction on the vector size, if we can.
2024 const NonTypeTemplateParmDecl *NTTP =
2025 getDeducedParameterFromExpr(Info, VectorParam->getSizeExpr());
2026 if (!NTTP)
2027 return Sema::TDK_Success;
2028
2029 llvm::APSInt ArgSize(S.Context.getTypeSize(S.Context.IntTy), false);
2030 ArgSize = VectorArg->getNumElements();
2031 // Note that we use the "array bound" rules here; just like in that
2032 // case, we don't have any particular type for the vector size, but
2033 // we can provide one if necessary.
2034 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, ArgSize,
2035 S.Context.UnsignedIntTy, true,
2036 Info, Deduced);
2037 }
2038
2039 if (const auto *VectorArg = dyn_cast<DependentVectorType>(Arg)) {
2040 // Perform deduction on the element types.
2041 if (Sema::TemplateDeductionResult Result =
2042 DeduceTemplateArgumentsByTypeMatch(
2043 S, TemplateParams, VectorParam->getElementType(),
2044 VectorArg->getElementType(), Info, Deduced, TDF))
2045 return Result;
2046
2047 // Perform deduction on the vector size, if we can.
2048 const NonTypeTemplateParmDecl *NTTP = getDeducedParameterFromExpr(
2049 Info, VectorParam->getSizeExpr());
2050 if (!NTTP)
2051 return Sema::TDK_Success;
2052
2053 return DeduceNonTypeTemplateArgument(
2054 S, TemplateParams, NTTP, VectorArg->getSizeExpr(), Info, Deduced);
2055 }
2056
2057 return Sema::TDK_NonDeducedMismatch;
2058 }
2059
2060 // (clang extension)
2061 //
2062 // T __attribute__(((ext_vector_type(N))))
2063 case Type::DependentSizedExtVector: {
2064 const DependentSizedExtVectorType *VectorParam
2065 = cast<DependentSizedExtVectorType>(Param);
2066
2067 if (const ExtVectorType *VectorArg = dyn_cast<ExtVectorType>(Arg)) {
2068 // Perform deduction on the element types.
2069 if (Sema::TemplateDeductionResult Result
2070 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
2071 VectorParam->getElementType(),
2072 VectorArg->getElementType(),
2073 Info, Deduced, TDF))
2074 return Result;
2075
2076 // Perform deduction on the vector size, if we can.
2077 const NonTypeTemplateParmDecl *NTTP =
2078 getDeducedParameterFromExpr(Info, VectorParam->getSizeExpr());
2079 if (!NTTP)
2080 return Sema::TDK_Success;
2081
2082 llvm::APSInt ArgSize(S.Context.getTypeSize(S.Context.IntTy), false);
2083 ArgSize = VectorArg->getNumElements();
2084 // Note that we use the "array bound" rules here; just like in that
2085 // case, we don't have any particular type for the vector size, but
2086 // we can provide one if necessary.
2087 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, ArgSize,
2088 S.Context.IntTy, true, Info,
2089 Deduced);
2090 }
2091
2092 if (const DependentSizedExtVectorType *VectorArg
2093 = dyn_cast<DependentSizedExtVectorType>(Arg)) {
2094 // Perform deduction on the element types.
2095 if (Sema::TemplateDeductionResult Result
2096 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
2097 VectorParam->getElementType(),
2098 VectorArg->getElementType(),
2099 Info, Deduced, TDF))
2100 return Result;
2101
2102 // Perform deduction on the vector size, if we can.
2103 const NonTypeTemplateParmDecl *NTTP =
2104 getDeducedParameterFromExpr(Info, VectorParam->getSizeExpr());
2105 if (!NTTP)
2106 return Sema::TDK_Success;
2107
2108 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
2109 VectorArg->getSizeExpr(),
2110 Info, Deduced);
2111 }
2112
2113 return Sema::TDK_NonDeducedMismatch;
2114 }
2115
2116 // (clang extension)
2117 //
2118 // T __attribute__((matrix_type(<integral constant>,
2119 // <integral constant>)))
2120 case Type::ConstantMatrix: {
2121 const ConstantMatrixType *MatrixArg = dyn_cast<ConstantMatrixType>(Arg);
2122 if (!MatrixArg)
2123 return Sema::TDK_NonDeducedMismatch;
2124
2125 const ConstantMatrixType *MatrixParam = cast<ConstantMatrixType>(Param);
2126 // Check that the dimensions are the same
2127 if (MatrixParam->getNumRows() != MatrixArg->getNumRows() ||
2128 MatrixParam->getNumColumns() != MatrixArg->getNumColumns()) {
2129 return Sema::TDK_NonDeducedMismatch;
2130 }
2131 // Perform deduction on element types.
2132 return DeduceTemplateArgumentsByTypeMatch(
2133 S, TemplateParams, MatrixParam->getElementType(),
2134 MatrixArg->getElementType(), Info, Deduced, TDF);
2135 }
2136
2137 case Type::DependentSizedMatrix: {
2138 const MatrixType *MatrixArg = dyn_cast<MatrixType>(Arg);
2139 if (!MatrixArg)
2140 return Sema::TDK_NonDeducedMismatch;
2141
2142 // Check the element type of the matrixes.
2143 const DependentSizedMatrixType *MatrixParam =
2144 cast<DependentSizedMatrixType>(Param);
2145 if (Sema::TemplateDeductionResult Result =
2146 DeduceTemplateArgumentsByTypeMatch(
2147 S, TemplateParams, MatrixParam->getElementType(),
2148 MatrixArg->getElementType(), Info, Deduced, TDF))
2149 return Result;
2150
2151 // Try to deduce a matrix dimension.
2152 auto DeduceMatrixArg =
2153 [&S, &Info, &Deduced, &TemplateParams](
2154 Expr *ParamExpr, const MatrixType *Arg,
2155 unsigned (ConstantMatrixType::*GetArgDimension)() const,
2156 Expr *(DependentSizedMatrixType::*GetArgDimensionExpr)() const) {
2157 const auto *ArgConstMatrix = dyn_cast<ConstantMatrixType>(Arg);
2158 const auto *ArgDepMatrix = dyn_cast<DependentSizedMatrixType>(Arg);
2159 if (!ParamExpr->isValueDependent()) {
2160 Optional<llvm::APSInt> ParamConst =
2161 ParamExpr->getIntegerConstantExpr(S.Context);
2162 if (!ParamConst)
2163 return Sema::TDK_NonDeducedMismatch;
2164
2165 if (ArgConstMatrix) {
2166 if ((ArgConstMatrix->*GetArgDimension)() == *ParamConst)
2167 return Sema::TDK_Success;
2168 return Sema::TDK_NonDeducedMismatch;
2169 }
2170
2171 Expr *ArgExpr = (ArgDepMatrix->*GetArgDimensionExpr)();
2172 if (!ArgExpr->isValueDependent())
2173 if (Optional<llvm::APSInt> ArgConst =
2174 ArgExpr->getIntegerConstantExpr(S.Context))
2175 if (*ArgConst == *ParamConst)
2176 return Sema::TDK_Success;
2177 return Sema::TDK_NonDeducedMismatch;
2178 }
2179
2180 const NonTypeTemplateParmDecl *NTTP =
2181 getDeducedParameterFromExpr(Info, ParamExpr);
2182 if (!NTTP)
2183 return Sema::TDK_Success;
2184
2185 if (ArgConstMatrix) {
2186 llvm::APSInt ArgConst(
2187 S.Context.getTypeSize(S.Context.getSizeType()));
2188 ArgConst = (ArgConstMatrix->*GetArgDimension)();
2189 return DeduceNonTypeTemplateArgument(
2190 S, TemplateParams, NTTP, ArgConst, S.Context.getSizeType(),
2191 /*ArrayBound=*/true, Info, Deduced);
2192 }
2193
2194 return DeduceNonTypeTemplateArgument(
2195 S, TemplateParams, NTTP, (ArgDepMatrix->*GetArgDimensionExpr)(),
2196 Info, Deduced);
2197 };
2198
2199 auto Result = DeduceMatrixArg(MatrixParam->getRowExpr(), MatrixArg,
2200 &ConstantMatrixType::getNumRows,
2201 &DependentSizedMatrixType::getRowExpr);
2202 if (Result)
2203 return Result;
2204
2205 return DeduceMatrixArg(MatrixParam->getColumnExpr(), MatrixArg,
2206 &ConstantMatrixType::getNumColumns,
2207 &DependentSizedMatrixType::getColumnExpr);
2208 }
2209
2210 // (clang extension)
2211 //
2212 // T __attribute__(((address_space(N))))
2213 case Type::DependentAddressSpace: {
2214 const DependentAddressSpaceType *AddressSpaceParam =
2215 cast<DependentAddressSpaceType>(Param);
2216
2217 if (const DependentAddressSpaceType *AddressSpaceArg =
2218 dyn_cast<DependentAddressSpaceType>(Arg)) {
2219 // Perform deduction on the pointer type.
2220 if (Sema::TemplateDeductionResult Result =
2221 DeduceTemplateArgumentsByTypeMatch(
2222 S, TemplateParams, AddressSpaceParam->getPointeeType(),
2223 AddressSpaceArg->getPointeeType(), Info, Deduced, TDF))
2224 return Result;
2225
2226 // Perform deduction on the address space, if we can.
2227 const NonTypeTemplateParmDecl *NTTP = getDeducedParameterFromExpr(
2228 Info, AddressSpaceParam->getAddrSpaceExpr());
2229 if (!NTTP)
2230 return Sema::TDK_Success;
2231
2232 return DeduceNonTypeTemplateArgument(
2233 S, TemplateParams, NTTP, AddressSpaceArg->getAddrSpaceExpr(), Info,
2234 Deduced);
2235 }
2236
2237 if (isTargetAddressSpace(Arg.getAddressSpace())) {
2238 llvm::APSInt ArgAddressSpace(S.Context.getTypeSize(S.Context.IntTy),
2239 false);
2240 ArgAddressSpace = toTargetAddressSpace(Arg.getAddressSpace());
2241
2242 // Perform deduction on the pointer types.
2243 if (Sema::TemplateDeductionResult Result =
2244 DeduceTemplateArgumentsByTypeMatch(
2245 S, TemplateParams, AddressSpaceParam->getPointeeType(),
2246 S.Context.removeAddrSpaceQualType(Arg), Info, Deduced, TDF))
2247 return Result;
2248
2249 // Perform deduction on the address space, if we can.
2250 const NonTypeTemplateParmDecl *NTTP = getDeducedParameterFromExpr(
2251 Info, AddressSpaceParam->getAddrSpaceExpr());
2252 if (!NTTP)
2253 return Sema::TDK_Success;
2254
2255 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
2256 ArgAddressSpace, S.Context.IntTy,
2257 true, Info, Deduced);
2258 }
2259
2260 return Sema::TDK_NonDeducedMismatch;
2261 }
2262 case Type::DependentExtInt: {
2263 const auto *IntParam = cast<DependentExtIntType>(Param);
2264
2265 if (const auto *IntArg = dyn_cast<ExtIntType>(Arg)){
2266 if (IntParam->isUnsigned() != IntArg->isUnsigned())
2267 return Sema::TDK_NonDeducedMismatch;
2268
2269 const NonTypeTemplateParmDecl *NTTP =
2270 getDeducedParameterFromExpr(Info, IntParam->getNumBitsExpr());
2271 if (!NTTP)
2272 return Sema::TDK_Success;
2273
2274 llvm::APSInt ArgSize(S.Context.getTypeSize(S.Context.IntTy), false);
2275 ArgSize = IntArg->getNumBits();
2276
2277 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, ArgSize,
2278 S.Context.IntTy, true, Info,
2279 Deduced);
2280 }
2281
2282 if (const auto *IntArg = dyn_cast<DependentExtIntType>(Arg)) {
2283 if (IntParam->isUnsigned() != IntArg->isUnsigned())
2284 return Sema::TDK_NonDeducedMismatch;
2285 return Sema::TDK_Success;
2286 }
2287 return Sema::TDK_NonDeducedMismatch;
2288 }
2289
2290 case Type::TypeOfExpr:
2291 case Type::TypeOf:
2292 case Type::DependentName:
2293 case Type::UnresolvedUsing:
2294 case Type::Decltype:
2295 case Type::UnaryTransform:
2296 case Type::Auto:
2297 case Type::DeducedTemplateSpecialization:
2298 case Type::DependentTemplateSpecialization:
2299 case Type::PackExpansion:
2300 case Type::Pipe:
2301 // No template argument deduction for these types
2302 return Sema::TDK_Success;
2303 }
2304
2305 llvm_unreachable("Invalid Type Class!")__builtin_unreachable();
2306}
2307
2308static Sema::TemplateDeductionResult
2309DeduceTemplateArguments(Sema &S,
2310 TemplateParameterList *TemplateParams,
2311 const TemplateArgument &Param,
2312 TemplateArgument Arg,
2313 TemplateDeductionInfo &Info,
2314 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
2315 // If the template argument is a pack expansion, perform template argument
2316 // deduction against the pattern of that expansion. This only occurs during
2317 // partial ordering.
2318 if (Arg.isPackExpansion())
2319 Arg = Arg.getPackExpansionPattern();
2320
2321 switch (Param.getKind()) {
2322 case TemplateArgument::Null:
2323 llvm_unreachable("Null template argument in parameter list")__builtin_unreachable();
2324
2325 case TemplateArgument::Type:
2326 if (Arg.getKind() == TemplateArgument::Type)
2327 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
2328 Param.getAsType(),
2329 Arg.getAsType(),
2330 Info, Deduced, 0);
2331 Info.FirstArg = Param;
2332 Info.SecondArg = Arg;
2333 return Sema::TDK_NonDeducedMismatch;
2334
2335 case TemplateArgument::Template:
2336 if (Arg.getKind() == TemplateArgument::Template)
2337 return DeduceTemplateArguments(S, TemplateParams,
2338 Param.getAsTemplate(),
2339 Arg.getAsTemplate(), Info, Deduced);
2340 Info.FirstArg = Param;
2341 Info.SecondArg = Arg;
2342 return Sema::TDK_NonDeducedMismatch;
2343
2344 case TemplateArgument::TemplateExpansion:
2345 llvm_unreachable("caller should handle pack expansions")__builtin_unreachable();
2346
2347 case TemplateArgument::Declaration:
2348 if (Arg.getKind() == TemplateArgument::Declaration &&
2349 isSameDeclaration(Param.getAsDecl(), Arg.getAsDecl()))
2350 return Sema::TDK_Success;
2351
2352 Info.FirstArg = Param;
2353 Info.SecondArg = Arg;
2354 return Sema::TDK_NonDeducedMismatch;
2355
2356 case TemplateArgument::NullPtr:
2357 if (Arg.getKind() == TemplateArgument::NullPtr &&
2358 S.Context.hasSameType(Param.getNullPtrType(), Arg.getNullPtrType()))
2359 return Sema::TDK_Success;
2360
2361 Info.FirstArg = Param;
2362 Info.SecondArg = Arg;
2363 return Sema::TDK_NonDeducedMismatch;
2364
2365 case TemplateArgument::Integral:
2366 if (Arg.getKind() == TemplateArgument::Integral) {
2367 if (hasSameExtendedValue(Param.getAsIntegral(), Arg.getAsIntegral()))
2368 return Sema::TDK_Success;
2369
2370 Info.FirstArg = Param;
2371 Info.SecondArg = Arg;
2372 return Sema::TDK_NonDeducedMismatch;
2373 }
2374
2375 if (Arg.getKind() == TemplateArgument::Expression) {
2376 Info.FirstArg = Param;
2377 Info.SecondArg = Arg;
2378 return Sema::TDK_NonDeducedMismatch;
2379 }
2380
2381 Info.FirstArg = Param;
2382 Info.SecondArg = Arg;
2383 return Sema::TDK_NonDeducedMismatch;
2384
2385 case TemplateArgument::Expression:
2386 if (const NonTypeTemplateParmDecl *NTTP =
2387 getDeducedParameterFromExpr(Info, Param.getAsExpr())) {
2388 if (Arg.getKind() == TemplateArgument::Integral)
2389 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
2390 Arg.getAsIntegral(),
2391 Arg.getIntegralType(),
2392 /*ArrayBound=*/false,
2393 Info, Deduced);
2394 if (Arg.getKind() == TemplateArgument::NullPtr)
2395 return DeduceNullPtrTemplateArgument(S, TemplateParams, NTTP,
2396 Arg.getNullPtrType(),
2397 Info, Deduced);
2398 if (Arg.getKind() == TemplateArgument::Expression)
2399 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
2400 Arg.getAsExpr(), Info, Deduced);
2401 if (Arg.getKind() == TemplateArgument::Declaration)
2402 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
2403 Arg.getAsDecl(),
2404 Arg.getParamTypeForDecl(),
2405 Info, Deduced);
2406
2407 Info.FirstArg = Param;
2408 Info.SecondArg = Arg;
2409 return Sema::TDK_NonDeducedMismatch;
2410 }
2411
2412 // Can't deduce anything, but that's okay.
2413 return Sema::TDK_Success;
2414
2415 case TemplateArgument::Pack:
2416 llvm_unreachable("Argument packs should be expanded by the caller!")__builtin_unreachable();
2417 }
2418
2419 llvm_unreachable("Invalid TemplateArgument Kind!")__builtin_unreachable();
2420}
2421
2422/// Determine whether there is a template argument to be used for
2423/// deduction.
2424///
2425/// This routine "expands" argument packs in-place, overriding its input
2426/// parameters so that \c Args[ArgIdx] will be the available template argument.
2427///
2428/// \returns true if there is another template argument (which will be at
2429/// \c Args[ArgIdx]), false otherwise.
2430static bool hasTemplateArgumentForDeduction(ArrayRef<TemplateArgument> &Args,
2431 unsigned &ArgIdx) {
2432 if (ArgIdx == Args.size())
2433 return false;
2434
2435 const TemplateArgument &Arg = Args[ArgIdx];
2436 if (Arg.getKind() != TemplateArgument::Pack)
2437 return true;
2438
2439 assert(ArgIdx == Args.size() - 1 && "Pack not at the end of argument list?")(static_cast<void> (0));
2440 Args = Arg.pack_elements();
2441 ArgIdx = 0;
2442 return ArgIdx < Args.size();
2443}
2444
2445/// Determine whether the given set of template arguments has a pack
2446/// expansion that is not the last template argument.
2447static bool hasPackExpansionBeforeEnd(ArrayRef<TemplateArgument> Args) {
2448 bool FoundPackExpansion = false;
2449 for (const auto &A : Args) {
2450 if (FoundPackExpansion)
2451 return true;
2452
2453 if (A.getKind() == TemplateArgument::Pack)
2454 return hasPackExpansionBeforeEnd(A.pack_elements());
2455
2456 // FIXME: If this is a fixed-arity pack expansion from an outer level of
2457 // templates, it should not be treated as a pack expansion.
2458 if (A.isPackExpansion())
2459 FoundPackExpansion = true;
2460 }
2461
2462 return false;
2463}
2464
2465static Sema::TemplateDeductionResult
2466DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams,
2467 ArrayRef<TemplateArgument> Params,
2468 ArrayRef<TemplateArgument> Args,
2469 TemplateDeductionInfo &Info,
2470 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
2471 bool NumberOfArgumentsMustMatch) {
2472 // C++0x [temp.deduct.type]p9:
2473 // If the template argument list of P contains a pack expansion that is not
2474 // the last template argument, the entire template argument list is a
2475 // non-deduced context.
2476 if (hasPackExpansionBeforeEnd(Params))
2477 return Sema::TDK_Success;
2478
2479 // C++0x [temp.deduct.type]p9:
2480 // If P has a form that contains <T> or <i>, then each argument Pi of the
2481 // respective template argument list P is compared with the corresponding
2482 // argument Ai of the corresponding template argument list of A.
2483 unsigned ArgIdx = 0, ParamIdx = 0;
2484 for (; hasTemplateArgumentForDeduction(Params, ParamIdx); ++ParamIdx) {
2485 if (!Params[ParamIdx].isPackExpansion()) {
2486 // The simple case: deduce template arguments by matching Pi and Ai.
2487
2488 // Check whether we have enough arguments.
2489 if (!hasTemplateArgumentForDeduction(Args, ArgIdx))
2490 return NumberOfArgumentsMustMatch
2491 ? Sema::TDK_MiscellaneousDeductionFailure
2492 : Sema::TDK_Success;
2493
2494 // C++1z [temp.deduct.type]p9:
2495 // During partial ordering, if Ai was originally a pack expansion [and]
2496 // Pi is not a pack expansion, template argument deduction fails.
2497 if (Args[ArgIdx].isPackExpansion())
2498 return Sema::TDK_MiscellaneousDeductionFailure;
2499
2500 // Perform deduction for this Pi/Ai pair.
2501 if (Sema::TemplateDeductionResult Result
2502 = DeduceTemplateArguments(S, TemplateParams,
2503 Params[ParamIdx], Args[ArgIdx],
2504 Info, Deduced))
2505 return Result;
2506
2507 // Move to the next argument.
2508 ++ArgIdx;
2509 continue;
2510 }
2511
2512 // The parameter is a pack expansion.
2513
2514 // C++0x [temp.deduct.type]p9:
2515 // If Pi is a pack expansion, then the pattern of Pi is compared with
2516 // each remaining argument in the template argument list of A. Each
2517 // comparison deduces template arguments for subsequent positions in the
2518 // template parameter packs expanded by Pi.
2519 TemplateArgument Pattern = Params[ParamIdx].getPackExpansionPattern();
2520
2521 // Prepare to deduce the packs within the pattern.
2522 PackDeductionScope PackScope(S, TemplateParams, Deduced, Info, Pattern);
2523
2524 // Keep track of the deduced template arguments for each parameter pack
2525 // expanded by this pack expansion (the outer index) and for each
2526 // template argument (the inner SmallVectors).
2527 for (; hasTemplateArgumentForDeduction(Args, ArgIdx) &&
2528 PackScope.hasNextElement();
2529 ++ArgIdx) {
2530 // Deduce template arguments from the pattern.
2531 if (Sema::TemplateDeductionResult Result
2532 = DeduceTemplateArguments(S, TemplateParams, Pattern, Args[ArgIdx],
2533 Info, Deduced))
2534 return Result;
2535
2536 PackScope.nextPackElement();
2537 }
2538
2539 // Build argument packs for each of the parameter packs expanded by this
2540 // pack expansion.
2541 if (auto Result = PackScope.finish())
2542 return Result;
2543 }
2544
2545 return Sema::TDK_Success;
2546}
2547
2548static Sema::TemplateDeductionResult
2549DeduceTemplateArguments(Sema &S,
2550 TemplateParameterList *TemplateParams,
2551 const TemplateArgumentList &ParamList,
2552 const TemplateArgumentList &ArgList,
2553 TemplateDeductionInfo &Info,
2554 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
2555 return DeduceTemplateArguments(S, TemplateParams, ParamList.asArray(),
2556 ArgList.asArray(), Info, Deduced,
2557 /*NumberOfArgumentsMustMatch*/false);
2558}
2559
2560/// Determine whether two template arguments are the same.
2561static bool isSameTemplateArg(ASTContext &Context,
2562 TemplateArgument X,
2563 const TemplateArgument &Y,
2564 bool PackExpansionMatchesPack = false) {
2565 // If we're checking deduced arguments (X) against original arguments (Y),
2566 // we will have flattened packs to non-expansions in X.
2567 if (PackExpansionMatchesPack && X.isPackExpansion() && !Y.isPackExpansion())
2568 X = X.getPackExpansionPattern();
2569
2570 if (X.getKind() != Y.getKind())
2571 return false;
2572
2573 switch (X.getKind()) {
2574 case TemplateArgument::Null:
2575 llvm_unreachable("Comparing NULL template argument")__builtin_unreachable();
2576
2577 case TemplateArgument::Type:
2578 return Context.getCanonicalType(X.getAsType()) ==
2579 Context.getCanonicalType(Y.getAsType());
2580
2581 case TemplateArgument::Declaration:
2582 return isSameDeclaration(X.getAsDecl(), Y.getAsDecl());
2583
2584 case TemplateArgument::NullPtr:
2585 return Context.hasSameType(X.getNullPtrType(), Y.getNullPtrType());
2586
2587 case TemplateArgument::Template:
2588 case TemplateArgument::TemplateExpansion:
2589 return Context.getCanonicalTemplateName(
2590 X.getAsTemplateOrTemplatePattern()).getAsVoidPointer() ==
2591 Context.getCanonicalTemplateName(
2592 Y.getAsTemplateOrTemplatePattern()).getAsVoidPointer();
2593
2594 case TemplateArgument::Integral:
2595 return hasSameExtendedValue(X.getAsIntegral(), Y.getAsIntegral());
2596
2597 case TemplateArgument::Expression: {
2598 llvm::FoldingSetNodeID XID, YID;
2599 X.getAsExpr()->Profile(XID, Context, true);
2600 Y.getAsExpr()->Profile(YID, Context, true);
2601 return XID == YID;
2602 }
2603
2604 case TemplateArgument::Pack:
2605 if (X.pack_size() != Y.pack_size())
2606 return false;
2607
2608 for (TemplateArgument::pack_iterator XP = X.pack_begin(),
2609 XPEnd = X.pack_end(),
2610 YP = Y.pack_begin();
2611 XP != XPEnd; ++XP, ++YP)
2612 if (!isSameTemplateArg(Context, *XP, *YP, PackExpansionMatchesPack))
2613 return false;
2614
2615 return true;
2616 }
2617
2618 llvm_unreachable("Invalid TemplateArgument Kind!")__builtin_unreachable();
2619}
2620
2621/// Allocate a TemplateArgumentLoc where all locations have
2622/// been initialized to the given location.
2623///
2624/// \param Arg The template argument we are producing template argument
2625/// location information for.
2626///
2627/// \param NTTPType For a declaration template argument, the type of
2628/// the non-type template parameter that corresponds to this template
2629/// argument. Can be null if no type sugar is available to add to the
2630/// type from the template argument.
2631///
2632/// \param Loc The source location to use for the resulting template
2633/// argument.
2634TemplateArgumentLoc
2635Sema::getTrivialTemplateArgumentLoc(const TemplateArgument &Arg,
2636 QualType NTTPType, SourceLocation Loc) {
2637 switch (Arg.getKind()) {
2638 case TemplateArgument::Null:
2639 llvm_unreachable("Can't get a NULL template argument here")__builtin_unreachable();
2640
2641 case TemplateArgument::Type:
2642 return TemplateArgumentLoc(
2643 Arg, Context.getTrivialTypeSourceInfo(Arg.getAsType(), Loc));
2644
2645 case TemplateArgument::Declaration: {
2646 if (NTTPType.isNull())
2647 NTTPType = Arg.getParamTypeForDecl();
2648 Expr *E = BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc)
2649 .getAs<Expr>();
2650 return TemplateArgumentLoc(TemplateArgument(E), E);
2651 }
2652
2653 case TemplateArgument::NullPtr: {
2654 if (NTTPType.isNull())
2655 NTTPType = Arg.getNullPtrType();
2656 Expr *E = BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc)
2657 .getAs<Expr>();
2658 return TemplateArgumentLoc(TemplateArgument(NTTPType, /*isNullPtr*/true),
2659 E);
2660 }
2661
2662 case TemplateArgument::Integral: {
2663 Expr *E =
2664 BuildExpressionFromIntegralTemplateArgument(Arg, Loc).getAs<Expr>();
2665 return TemplateArgumentLoc(TemplateArgument(E), E);
2666 }
2667
2668 case TemplateArgument::Template:
2669 case TemplateArgument::TemplateExpansion: {
2670 NestedNameSpecifierLocBuilder Builder;
2671 TemplateName Template = Arg.getAsTemplateOrTemplatePattern();
2672 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName())
2673 Builder.MakeTrivial(Context, DTN->getQualifier(), Loc);
2674 else if (QualifiedTemplateName *QTN =
2675 Template.getAsQualifiedTemplateName())
2676 Builder.MakeTrivial(Context, QTN->getQualifier(), Loc);
2677
2678 if (Arg.getKind() == TemplateArgument::Template)
2679 return TemplateArgumentLoc(Context, Arg,
2680 Builder.getWithLocInContext(Context), Loc);
2681
2682 return TemplateArgumentLoc(
2683 Context, Arg, Builder.getWithLocInContext(Context), Loc, Loc);
2684 }
2685
2686 case TemplateArgument::Expression:
2687 return TemplateArgumentLoc(Arg, Arg.getAsExpr());
2688
2689 case TemplateArgument::Pack:
2690 return TemplateArgumentLoc(Arg, TemplateArgumentLocInfo());
2691 }
2692
2693 llvm_unreachable("Invalid TemplateArgument Kind!")__builtin_unreachable();
2694}
2695
2696TemplateArgumentLoc
2697Sema::getIdentityTemplateArgumentLoc(NamedDecl *TemplateParm,
2698 SourceLocation Location) {
2699 return getTrivialTemplateArgumentLoc(
2700 Context.getInjectedTemplateArg(TemplateParm), QualType(), Location);
2701}
2702
2703/// Convert the given deduced template argument and add it to the set of
2704/// fully-converted template arguments.
2705static bool
2706ConvertDeducedTemplateArgument(Sema &S, NamedDecl *Param,
2707 DeducedTemplateArgument Arg,
2708 NamedDecl *Template,
2709 TemplateDeductionInfo &Info,
2710 bool IsDeduced,
2711 SmallVectorImpl<TemplateArgument> &Output) {
2712 auto ConvertArg = [&](DeducedTemplateArgument Arg,
2713 unsigned ArgumentPackIndex) {
2714 // Convert the deduced template argument into a template
2715 // argument that we can check, almost as if the user had written
2716 // the template argument explicitly.
2717 TemplateArgumentLoc ArgLoc =
2718 S.getTrivialTemplateArgumentLoc(Arg, QualType(), Info.getLocation());
2719
2720 // Check the template argument, converting it as necessary.
2721 return S.CheckTemplateArgument(
2722 Param, ArgLoc, Template, Template->getLocation(),
2723 Template->getSourceRange().getEnd(), ArgumentPackIndex, Output,
2724 IsDeduced
2725 ? (Arg.wasDeducedFromArrayBound() ? Sema::CTAK_DeducedFromArrayBound
2726 : Sema::CTAK_Deduced)
2727 : Sema::CTAK_Specified);
2728 };
2729
2730 if (Arg.getKind() == TemplateArgument::Pack) {
2731 // This is a template argument pack, so check each of its arguments against
2732 // the template parameter.
2733 SmallVector<TemplateArgument, 2> PackedArgsBuilder;
2734 for (const auto &P : Arg.pack_elements()) {
2735 // When converting the deduced template argument, append it to the
2736 // general output list. We need to do this so that the template argument
2737 // checking logic has all of the prior template arguments available.
2738 DeducedTemplateArgument InnerArg(P);
2739 InnerArg.setDeducedFromArrayBound(Arg.wasDeducedFromArrayBound());
2740 assert(InnerArg.getKind() != TemplateArgument::Pack &&(static_cast<void> (0))
2741 "deduced nested pack")(static_cast<void> (0));
2742 if (P.isNull()) {
2743 // We deduced arguments for some elements of this pack, but not for
2744 // all of them. This happens if we get a conditionally-non-deduced
2745 // context in a pack expansion (such as an overload set in one of the
2746 // arguments).
2747 S.Diag(Param->getLocation(),
2748 diag::err_template_arg_deduced_incomplete_pack)
2749 << Arg << Param;
2750 return true;
2751 }
2752 if (ConvertArg(InnerArg, PackedArgsBuilder.size()))
2753 return true;
2754
2755 // Move the converted template argument into our argument pack.
2756 PackedArgsBuilder.push_back(Output.pop_back_val());
2757 }
2758
2759 // If the pack is empty, we still need to substitute into the parameter
2760 // itself, in case that substitution fails.
2761 if (PackedArgsBuilder.empty()) {
2762 LocalInstantiationScope Scope(S);
2763 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Output);
2764 MultiLevelTemplateArgumentList Args(TemplateArgs);
2765
2766 if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
2767 Sema::InstantiatingTemplate Inst(S, Template->getLocation(), Template,
2768 NTTP, Output,
2769 Template->getSourceRange());
2770 if (Inst.isInvalid() ||
2771 S.SubstType(NTTP->getType(), Args, NTTP->getLocation(),
2772 NTTP->getDeclName()).isNull())
2773 return true;
2774 } else if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(Param)) {
2775 Sema::InstantiatingTemplate Inst(S, Template->getLocation(), Template,
2776 TTP, Output,
2777 Template->getSourceRange());
2778 if (Inst.isInvalid() || !S.SubstDecl(TTP, S.CurContext, Args))
2779 return true;
2780 }
2781 // For type parameters, no substitution is ever required.
2782 }
2783
2784 // Create the resulting argument pack.
2785 Output.push_back(
2786 TemplateArgument::CreatePackCopy(S.Context, PackedArgsBuilder));
2787 return false;
2788 }
2789
2790 return ConvertArg(Arg, 0);
2791}
2792
2793// FIXME: This should not be a template, but
2794// ClassTemplatePartialSpecializationDecl sadly does not derive from
2795// TemplateDecl.
2796template<typename TemplateDeclT>
2797static Sema::TemplateDeductionResult ConvertDeducedTemplateArguments(
2798 Sema &S, TemplateDeclT *Template, bool IsDeduced,
2799 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
2800 TemplateDeductionInfo &Info, SmallVectorImpl<TemplateArgument> &Builder,
2801 LocalInstantiationScope *CurrentInstantiationScope = nullptr,
2802 unsigned NumAlreadyConverted = 0, bool PartialOverloading = false) {
2803 TemplateParameterList *TemplateParams = Template->getTemplateParameters();
2804
2805 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
2806 NamedDecl *Param = TemplateParams->getParam(I);
2807
2808 // C++0x [temp.arg.explicit]p3:
2809 // A trailing template parameter pack (14.5.3) not otherwise deduced will
2810 // be deduced to an empty sequence of template arguments.
2811 // FIXME: Where did the word "trailing" come from?
2812 if (Deduced[I].isNull() && Param->isTemplateParameterPack()) {
2813 if (auto Result =
2814 PackDeductionScope(S, TemplateParams, Deduced, Info, I).finish())
2815 return Result;
2816 }
2817
2818 if (!Deduced[I].isNull()) {
2819 if (I < NumAlreadyConverted) {
2820 // We may have had explicitly-specified template arguments for a
2821 // template parameter pack (that may or may not have been extended
2822 // via additional deduced arguments).
2823 if (Param->isParameterPack() && CurrentInstantiationScope &&
2824 CurrentInstantiationScope->getPartiallySubstitutedPack() == Param) {
2825 // Forget the partially-substituted pack; its substitution is now
2826 // complete.
2827 CurrentInstantiationScope->ResetPartiallySubstitutedPack();
2828 // We still need to check the argument in case it was extended by
2829 // deduction.
2830 } else {
2831 // We have already fully type-checked and converted this
2832 // argument, because it was explicitly-specified. Just record the
2833 // presence of this argument.
2834 Builder.push_back(Deduced[I]);
2835 continue;
2836 }
2837 }
2838
2839 // We may have deduced this argument, so it still needs to be
2840 // checked and converted.
2841 if (ConvertDeducedTemplateArgument(S, Param, Deduced[I], Template, Info,
2842 IsDeduced, Builder)) {
2843 Info.Param = makeTemplateParameter(Param);
2844 // FIXME: These template arguments are temporary. Free them!
2845 Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder));
2846 return Sema::TDK_SubstitutionFailure;
2847 }
2848
2849 continue;
2850 }
2851
2852 // Substitute into the default template argument, if available.
2853 bool HasDefaultArg = false;
2854 TemplateDecl *TD = dyn_cast<TemplateDecl>(Template);
2855 if (!TD) {
2856 assert(isa<ClassTemplatePartialSpecializationDecl>(Template) ||(static_cast<void> (0))
2857 isa<VarTemplatePartialSpecializationDecl>(Template))(static_cast<void> (0));
2858 return Sema::TDK_Incomplete;
2859 }
2860
2861 TemplateArgumentLoc DefArg = S.SubstDefaultTemplateArgumentIfAvailable(
2862 TD, TD->getLocation(), TD->getSourceRange().getEnd(), Param, Builder,
2863 HasDefaultArg);
2864
2865 // If there was no default argument, deduction is incomplete.
2866 if (DefArg.getArgument().isNull()) {
2867 Info.Param = makeTemplateParameter(
2868 const_cast<NamedDecl *>(TemplateParams->getParam(I)));
2869 Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder));
2870 if (PartialOverloading) break;
2871
2872 return HasDefaultArg ? Sema::TDK_SubstitutionFailure
2873 : Sema::TDK_Incomplete;
2874 }
2875
2876 // Check whether we can actually use the default argument.
2877 if (S.CheckTemplateArgument(Param, DefArg, TD, TD->getLocation(),
2878 TD->getSourceRange().getEnd(), 0, Builder,
2879 Sema::CTAK_Specified)) {
2880 Info.Param = makeTemplateParameter(
2881 const_cast<NamedDecl *>(TemplateParams->getParam(I)));
2882 // FIXME: These template arguments are temporary. Free them!
2883 Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder));
2884 return Sema::TDK_SubstitutionFailure;
2885 }
2886
2887 // If we get here, we successfully used the default template argument.
2888 }
2889
2890 return Sema::TDK_Success;
2891}
2892
2893static DeclContext *getAsDeclContextOrEnclosing(Decl *D) {
2894 if (auto *DC = dyn_cast<DeclContext>(D))
2895 return DC;
2896 return D->getDeclContext();
2897}
2898
2899template<typename T> struct IsPartialSpecialization {
2900 static constexpr bool value = false;
2901};
2902template<>
2903struct IsPartialSpecialization<ClassTemplatePartialSpecializationDecl> {
2904 static constexpr bool value = true;
2905};
2906template<>
2907struct IsPartialSpecialization<VarTemplatePartialSpecializationDecl> {
2908 static constexpr bool value = true;
2909};
2910
2911template<typename TemplateDeclT>
2912static Sema::TemplateDeductionResult
2913CheckDeducedArgumentConstraints(Sema& S, TemplateDeclT *Template,
2914 ArrayRef<TemplateArgument> DeducedArgs,
2915 TemplateDeductionInfo& Info) {
2916 llvm::SmallVector<const Expr *, 3> AssociatedConstraints;
2917 Template->getAssociatedConstraints(AssociatedConstraints);
2918 if (S.CheckConstraintSatisfaction(Template, AssociatedConstraints,
2919 DeducedArgs, Info.getLocation(),
2920 Info.AssociatedConstraintsSatisfaction) ||
2921 !Info.AssociatedConstraintsSatisfaction.IsSatisfied) {
2922 Info.reset(TemplateArgumentList::CreateCopy(S.Context, DeducedArgs));
2923 return Sema::TDK_ConstraintsNotSatisfied;
2924 }
2925 return Sema::TDK_Success;
2926}
2927
2928/// Complete template argument deduction for a partial specialization.
2929template <typename T>
2930static std::enable_if_t<IsPartialSpecialization<T>::value,
2931 Sema::TemplateDeductionResult>
2932FinishTemplateArgumentDeduction(
2933 Sema &S, T *Partial, bool IsPartialOrdering,
2934 const TemplateArgumentList &TemplateArgs,
2935 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
2936 TemplateDeductionInfo &Info) {
2937 // Unevaluated SFINAE context.
2938 EnterExpressionEvaluationContext Unevaluated(
2939 S, Sema::ExpressionEvaluationContext::Unevaluated);
2940 Sema::SFINAETrap Trap(S);
2941
2942 Sema::ContextRAII SavedContext(S, getAsDeclContextOrEnclosing(Partial));
2943
2944 // C++ [temp.deduct.type]p2:
2945 // [...] or if any template argument remains neither deduced nor
2946 // explicitly specified, template argument deduction fails.
2947 SmallVector<TemplateArgument, 4> Builder;
2948 if (auto Result = ConvertDeducedTemplateArguments(
2949 S, Partial, IsPartialOrdering, Deduced, Info, Builder))
2950 return Result;
2951
2952 // Form the template argument list from the deduced template arguments.
2953 TemplateArgumentList *DeducedArgumentList
2954 = TemplateArgumentList::CreateCopy(S.Context, Builder);
2955
2956 Info.reset(DeducedArgumentList);
2957
2958 // Substitute the deduced template arguments into the template
2959 // arguments of the class template partial specialization, and
2960 // verify that the instantiated template arguments are both valid
2961 // and are equivalent to the template arguments originally provided
2962 // to the class template.
2963 LocalInstantiationScope InstScope(S);
2964 auto *Template = Partial->getSpecializedTemplate();
2965 const ASTTemplateArgumentListInfo *PartialTemplArgInfo =
2966 Partial->getTemplateArgsAsWritten();
2967 const TemplateArgumentLoc *PartialTemplateArgs =
2968 PartialTemplArgInfo->getTemplateArgs();
2969
2970 TemplateArgumentListInfo InstArgs(PartialTemplArgInfo->LAngleLoc,
2971 PartialTemplArgInfo->RAngleLoc);
2972
2973 if (S.Subst(PartialTemplateArgs, PartialTemplArgInfo->NumTemplateArgs,
2974 InstArgs, MultiLevelTemplateArgumentList(*DeducedArgumentList))) {
2975 unsigned ArgIdx = InstArgs.size(), ParamIdx = ArgIdx;
2976 if (ParamIdx >= Partial->getTemplateParameters()->size())
2977 ParamIdx = Partial->getTemplateParameters()->size() - 1;
2978
2979 Decl *Param = const_cast<NamedDecl *>(
2980 Partial->getTemplateParameters()->getParam(ParamIdx));
2981 Info.Param = makeTemplateParameter(Param);
2982 Info.FirstArg = PartialTemplateArgs[ArgIdx].getArgument();
2983 return Sema::TDK_SubstitutionFailure;
2984 }
2985
2986 bool ConstraintsNotSatisfied;
2987 SmallVector<TemplateArgument, 4> ConvertedInstArgs;
2988 if (S.CheckTemplateArgumentList(Template, Partial->getLocation(), InstArgs,
2989 false, ConvertedInstArgs,
2990 /*UpdateArgsWithConversions=*/true,
2991 &ConstraintsNotSatisfied))
2992 return ConstraintsNotSatisfied ? Sema::TDK_ConstraintsNotSatisfied :
2993 Sema::TDK_SubstitutionFailure;
2994
2995 TemplateParameterList *TemplateParams = Template->getTemplateParameters();
2996 for (unsigned I = 0, E = TemplateParams->size(); I != E; ++I) {
2997 TemplateArgument InstArg = ConvertedInstArgs.data()[I];
2998 if (!isSameTemplateArg(S.Context, TemplateArgs[I], InstArg)) {
2999 Info.Param = makeTemplateParameter(TemplateParams->getParam(I));
3000 Info.FirstArg = TemplateArgs[I];
3001 Info.SecondArg = InstArg;
3002 return Sema::TDK_NonDeducedMismatch;
3003 }
3004 }
3005
3006 if (Trap.hasErrorOccurred())
3007 return Sema::TDK_SubstitutionFailure;
3008
3009 if (auto Result = CheckDeducedArgumentConstraints(S, Partial, Builder, Info))
3010 return Result;
3011
3012 return Sema::TDK_Success;
3013}
3014
3015/// Complete template argument deduction for a class or variable template,
3016/// when partial ordering against a partial specialization.
3017// FIXME: Factor out duplication with partial specialization version above.
3018static Sema::TemplateDeductionResult FinishTemplateArgumentDeduction(
3019 Sema &S, TemplateDecl *Template, bool PartialOrdering,
3020 const TemplateArgumentList &TemplateArgs,
3021 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
3022 TemplateDeductionInfo &Info) {
3023 // Unevaluated SFINAE context.
3024 EnterExpressionEvaluationContext Unevaluated(
3025 S, Sema::ExpressionEvaluationContext::Unevaluated);
3026 Sema::SFINAETrap Trap(S);
3027
3028 Sema::ContextRAII SavedContext(S, getAsDeclContextOrEnclosing(Template));
3029
3030 // C++ [temp.deduct.type]p2:
3031 // [...] or if any template argument remains neither deduced nor
3032 // explicitly specified, template argument deduction fails.
3033 SmallVector<TemplateArgument, 4> Builder;
3034 if (auto Result = ConvertDeducedTemplateArguments(
3035 S, Template, /*IsDeduced*/PartialOrdering, Deduced, Info, Builder))
3036 return Result;
3037
3038 // Check that we produced the correct argument list.
3039 TemplateParameterList *TemplateParams = Template->getTemplateParameters();
3040 for (unsigned I = 0, E = TemplateParams->size(); I != E; ++I) {
3041 TemplateArgument InstArg = Builder[I];
3042 if (!isSameTemplateArg(S.Context, TemplateArgs[I], InstArg,
3043 /*PackExpansionMatchesPack*/true)) {
3044 Info.Param = makeTemplateParameter(TemplateParams->getParam(I));
3045 Info.FirstArg = TemplateArgs[I];
3046 Info.SecondArg = InstArg;
3047 return Sema::TDK_NonDeducedMismatch;
3048 }
3049 }
3050
3051 if (Trap.hasErrorOccurred())
3052 return Sema::TDK_SubstitutionFailure;
3053
3054 if (auto Result = CheckDeducedArgumentConstraints(S, Template, Builder,
3055 Info))
3056 return Result;
3057
3058 return Sema::TDK_Success;
3059}
3060
3061/// Perform template argument deduction to determine whether
3062/// the given template arguments match the given class template
3063/// partial specialization per C++ [temp.class.spec.match].
3064Sema::TemplateDeductionResult
3065Sema::DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial,
3066 const TemplateArgumentList &TemplateArgs,
3067 TemplateDeductionInfo &Info) {
3068 if (Partial->isInvalidDecl())
3069 return TDK_Invalid;
3070
3071 // C++ [temp.class.spec.match]p2:
3072 // A partial specialization matches a given actual template
3073 // argument list if the template arguments of the partial
3074 // specialization can be deduced from the actual template argument
3075 // list (14.8.2).
3076
3077 // Unevaluated SFINAE context.
3078 EnterExpressionEvaluationContext Unevaluated(
3079 *this, Sema::ExpressionEvaluationContext::Unevaluated);
3080 SFINAETrap Trap(*this);
3081
3082 // This deduction has no relation to any outer instantiation we might be
3083 // performing.
3084 LocalInstantiationScope InstantiationScope(*this);
3085
3086 SmallVector<DeducedTemplateArgument, 4> Deduced;
3087 Deduced.resize(Partial->getTemplateParameters()->size());
3088 if (TemplateDeductionResult Result
3089 = ::DeduceTemplateArguments(*this,
3090 Partial->getTemplateParameters(),
3091 Partial->getTemplateArgs(),
3092 TemplateArgs, Info, Deduced))
3093 return Result;
3094
3095 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end());
3096 InstantiatingTemplate Inst(*this, Info.getLocation(), Partial, DeducedArgs,
3097 Info);
3098 if (Inst.isInvalid())
3099 return TDK_InstantiationDepth;
3100
3101 if (Trap.hasErrorOccurred())
3102 return Sema::TDK_SubstitutionFailure;
3103
3104 TemplateDeductionResult Result;
3105 runWithSufficientStackSpace(Info.getLocation(), [&] {
3106 Result = ::FinishTemplateArgumentDeduction(*this, Partial,
3107 /*IsPartialOrdering=*/false,
3108 TemplateArgs, Deduced, Info);
3109 });
3110 return Result;
3111}
3112
3113/// Perform template argument deduction to determine whether
3114/// the given template arguments match the given variable template
3115/// partial specialization per C++ [temp.class.spec.match].
3116Sema::TemplateDeductionResult
3117Sema::DeduceTemplateArguments(VarTemplatePartialSpecializationDecl *Partial,
3118 const TemplateArgumentList &TemplateArgs,
3119 TemplateDeductionInfo &Info) {
3120 if (Partial->isInvalidDecl())
3121 return TDK_Invalid;
3122
3123 // C++ [temp.class.spec.match]p2:
3124 // A partial specialization matches a given actual template
3125 // argument list if the template arguments of the partial
3126 // specialization can be deduced from the actual template argument
3127 // list (14.8.2).
3128
3129 // Unevaluated SFINAE context.
3130 EnterExpressionEvaluationContext Unevaluated(
3131 *this, Sema::ExpressionEvaluationContext::Unevaluated);
3132 SFINAETrap Trap(*this);
3133
3134 // This deduction has no relation to any outer instantiation we might be
3135 // performing.
3136 LocalInstantiationScope InstantiationScope(*this);
3137
3138 SmallVector<DeducedTemplateArgument, 4> Deduced;
3139 Deduced.resize(Partial->getTemplateParameters()->size());
3140 if (TemplateDeductionResult Result = ::DeduceTemplateArguments(
3141 *this, Partial->getTemplateParameters(), Partial->getTemplateArgs(),
3142 TemplateArgs, Info, Deduced))
3143 return Result;
3144
3145 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end());
3146 InstantiatingTemplate Inst(*this, Info.getLocation(), Partial, DeducedArgs,
3147 Info);
3148 if (Inst.isInvalid())
3149 return TDK_InstantiationDepth;
3150
3151 if (Trap.hasErrorOccurred())
3152 return Sema::TDK_SubstitutionFailure;
3153
3154 TemplateDeductionResult Result;
3155 runWithSufficientStackSpace(Info.getLocation(), [&] {
3156 Result = ::FinishTemplateArgumentDeduction(*this, Partial,
3157 /*IsPartialOrdering=*/false,
3158 TemplateArgs, Deduced, Info);
3159 });
3160 return Result;
3161}
3162
3163/// Determine whether the given type T is a simple-template-id type.
3164static bool isSimpleTemplateIdType(QualType T) {
3165 if (const TemplateSpecializationType *Spec
3166 = T->getAs<TemplateSpecializationType>())
3167 return Spec->getTemplateName().getAsTemplateDecl() != nullptr;
3168
3169 // C++17 [temp.local]p2:
3170 // the injected-class-name [...] is equivalent to the template-name followed
3171 // by the template-arguments of the class template specialization or partial
3172 // specialization enclosed in <>
3173 // ... which means it's equivalent to a simple-template-id.
3174 //
3175 // This only arises during class template argument deduction for a copy
3176 // deduction candidate, where it permits slicing.
3177 if (T->getAs<InjectedClassNameType>())
3178 return true;
3179
3180 return false;
3181}
3182
3183/// Substitute the explicitly-provided template arguments into the
3184/// given function template according to C++ [temp.arg.explicit].
3185///
3186/// \param FunctionTemplate the function template into which the explicit
3187/// template arguments will be substituted.
3188///
3189/// \param ExplicitTemplateArgs the explicitly-specified template
3190/// arguments.
3191///
3192/// \param Deduced the deduced template arguments, which will be populated
3193/// with the converted and checked explicit template arguments.
3194///
3195/// \param ParamTypes will be populated with the instantiated function
3196/// parameters.
3197///
3198/// \param FunctionType if non-NULL, the result type of the function template
3199/// will also be instantiated and the pointed-to value will be updated with
3200/// the instantiated function type.
3201///
3202/// \param Info if substitution fails for any reason, this object will be
3203/// populated with more information about the failure.
3204///
3205/// \returns TDK_Success if substitution was successful, or some failure
3206/// condition.
3207Sema::TemplateDeductionResult
3208Sema::SubstituteExplicitTemplateArguments(
3209 FunctionTemplateDecl *FunctionTemplate,
3210 TemplateArgumentListInfo &ExplicitTemplateArgs,
3211 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
3212 SmallVectorImpl<QualType> &ParamTypes,
3213 QualType *FunctionType,
3214 TemplateDeductionInfo &Info) {
3215 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
3216 TemplateParameterList *TemplateParams
3217 = FunctionTemplate->getTemplateParameters();
3218
3219 if (ExplicitTemplateArgs.size() == 0) {
2
Assuming the condition is false
3
Taking false branch
3220 // No arguments to substitute; just copy over the parameter types and
3221 // fill in the function type.
3222 for (auto P : Function->parameters())
3223 ParamTypes.push_back(P->getType());
3224
3225 if (FunctionType)
3226 *FunctionType = Function->getType();
3227 return TDK_Success;
3228 }
3229
3230 // Unevaluated SFINAE context.
3231 EnterExpressionEvaluationContext Unevaluated(
3232 *this, Sema::ExpressionEvaluationContext::Unevaluated);
3233 SFINAETrap Trap(*this);
3234
3235 // C++ [temp.arg.explicit]p3:
3236 // Template arguments that are present shall be specified in the
3237 // declaration order of their corresponding template-parameters. The
3238 // template argument list shall not specify more template-arguments than
3239 // there are corresponding template-parameters.
3240 SmallVector<TemplateArgument, 4> Builder;
3241
3242 // Enter a new template instantiation context where we check the
3243 // explicitly-specified template arguments against this function template,
3244 // and then substitute them into the function parameter types.
3245 SmallVector<TemplateArgument, 4> DeducedArgs;
3246 InstantiatingTemplate Inst(
3247 *this, Info.getLocation(), FunctionTemplate, DeducedArgs,
3248 CodeSynthesisContext::ExplicitTemplateArgumentSubstitution, Info);
3249 if (Inst.isInvalid())
4
Assuming the condition is false
3250 return TDK_InstantiationDepth;
3251
3252 if (CheckTemplateArgumentList(FunctionTemplate, SourceLocation(),
5
Assuming the condition is false
6
Taking false branch
3253 ExplicitTemplateArgs, true, Builder, false) ||
3254 Trap.hasErrorOccurred()) {
3255 unsigned Index = Builder.size();
3256 if (Index >= TemplateParams->size())
3257 return TDK_SubstitutionFailure;
3258 Info.Param = makeTemplateParameter(TemplateParams->getParam(Index));
3259 return TDK_InvalidExplicitArguments;
3260 }
3261
3262 // Form the template argument list from the explicitly-specified
3263 // template arguments.
3264 TemplateArgumentList *ExplicitArgumentList
3265 = TemplateArgumentList::CreateCopy(Context, Builder);
3266 Info.setExplicitArgs(ExplicitArgumentList);
3267
3268 // Template argument deduction and the final substitution should be
3269 // done in the context of the templated declaration. Explicit
3270 // argument substitution, on the other hand, needs to happen in the
3271 // calling context.
3272 ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl());
3273
3274 // If we deduced template arguments for a template parameter pack,
3275 // note that the template argument pack is partially substituted and record
3276 // the explicit template arguments. They'll be used as part of deduction
3277 // for this template parameter pack.
3278 unsigned PartiallySubstitutedPackIndex = -1u;
3279 if (!Builder.empty()) {
7
Taking false branch
3280 const TemplateArgument &Arg = Builder.back();
3281 if (Arg.getKind() == TemplateArgument::Pack) {
3282 auto *Param = TemplateParams->getParam(Builder.size() - 1);
3283 // If this is a fully-saturated fixed-size pack, it should be
3284 // fully-substituted, not partially-substituted.
3285 Optional<unsigned> Expansions = getExpandedPackSize(Param);
3286 if (!Expansions || Arg.pack_size() < *Expansions) {
3287 PartiallySubstitutedPackIndex = Builder.size() - 1;
3288 CurrentInstantiationScope->SetPartiallySubstitutedPack(
3289 Param, Arg.pack_begin(), Arg.pack_size());
3290 }
3291 }
3292 }
3293
3294 const FunctionProtoType *Proto
9
'Proto' initialized to a null pointer value
3295 = Function->getType()->getAs<FunctionProtoType>();
8
Assuming the object is not a 'FunctionProtoType'
3296 assert(Proto && "Function template does not have a prototype?")(static_cast<void> (0));
3297
3298 // Isolate our substituted parameters from our caller.
3299 LocalInstantiationScope InstScope(*this, /*MergeWithOuterScope*/true);
3300
3301 ExtParameterInfoBuilder ExtParamInfos;
3302
3303 // Instantiate the types of each of the function parameters given the
3304 // explicitly-specified template arguments. If the function has a trailing
3305 // return type, substitute it after the arguments to ensure we substitute
3306 // in lexical order.
3307 if (Proto->hasTrailingReturn()) {
10
Called C++ object pointer is null
3308 if (SubstParmTypes(Function->getLocation(), Function->parameters(),
3309 Proto->getExtParameterInfosOrNull(),
3310 MultiLevelTemplateArgumentList(*ExplicitArgumentList),
3311 ParamTypes, /*params*/ nullptr, ExtParamInfos))
3312 return TDK_SubstitutionFailure;
3313 }
3314
3315 // Instantiate the return type.
3316 QualType ResultType;
3317 {
3318 // C++11 [expr.prim.general]p3:
3319 // If a declaration declares a member function or member function
3320 // template of a class X, the expression this is a prvalue of type
3321 // "pointer to cv-qualifier-seq X" between the optional cv-qualifer-seq
3322 // and the end of the function-definition, member-declarator, or
3323 // declarator.
3324 Qualifiers ThisTypeQuals;
3325 CXXRecordDecl *ThisContext = nullptr;
3326 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) {
3327 ThisContext = Method->getParent();
3328 ThisTypeQuals = Method->getMethodQualifiers();
3329 }
3330
3331 CXXThisScopeRAII ThisScope(*this, ThisContext, ThisTypeQuals,
3332 getLangOpts().CPlusPlus11);
3333
3334 ResultType =
3335 SubstType(Proto->getReturnType(),
3336 MultiLevelTemplateArgumentList(*ExplicitArgumentList),
3337 Function->getTypeSpecStartLoc(), Function->getDeclName());
3338 if (ResultType.isNull() || Trap.hasErrorOccurred())
3339 return TDK_SubstitutionFailure;
3340 // CUDA: Kernel function must have 'void' return type.
3341 if (getLangOpts().CUDA)
3342 if (Function->hasAttr<CUDAGlobalAttr>() && !ResultType->isVoidType()) {
3343 Diag(Function->getLocation(), diag::err_kern_type_not_void_return)
3344 << Function->getType() << Function->getSourceRange();
3345 return TDK_SubstitutionFailure;
3346 }
3347 }
3348
3349 // Instantiate the types of each of the function parameters given the
3350 // explicitly-specified template arguments if we didn't do so earlier.
3351 if (!Proto->hasTrailingReturn() &&
3352 SubstParmTypes(Function->getLocation(), Function->parameters(),
3353 Proto->getExtParameterInfosOrNull(),
3354 MultiLevelTemplateArgumentList(*ExplicitArgumentList),
3355 ParamTypes, /*params*/ nullptr, ExtParamInfos))
3356 return TDK_SubstitutionFailure;
3357
3358 if (FunctionType) {
3359 auto EPI = Proto->getExtProtoInfo();
3360 EPI.ExtParameterInfos = ExtParamInfos.getPointerOrNull(ParamTypes.size());
3361
3362 // In C++1z onwards, exception specifications are part of the function type,
3363 // so substitution into the type must also substitute into the exception
3364 // specification.
3365 SmallVector<QualType, 4> ExceptionStorage;
3366 if (getLangOpts().CPlusPlus17 &&
3367 SubstExceptionSpec(
3368 Function->getLocation(), EPI.ExceptionSpec, ExceptionStorage,
3369 MultiLevelTemplateArgumentList(*ExplicitArgumentList)))
3370 return TDK_SubstitutionFailure;
3371
3372 *FunctionType = BuildFunctionType(ResultType, ParamTypes,
3373 Function->getLocation(),
3374 Function->getDeclName(),
3375 EPI);
3376 if (FunctionType->isNull() || Trap.hasErrorOccurred())
3377 return TDK_SubstitutionFailure;
3378 }
3379
3380 // C++ [temp.arg.explicit]p2:
3381 // Trailing template arguments that can be deduced (14.8.2) may be
3382 // omitted from the list of explicit template-arguments. If all of the
3383 // template arguments can be deduced, they may all be omitted; in this
3384 // case, the empty template argument list <> itself may also be omitted.
3385 //
3386 // Take all of the explicitly-specified arguments and put them into
3387 // the set of deduced template arguments. The partially-substituted
3388 // parameter pack, however, will be set to NULL since the deduction
3389 // mechanism handles the partially-substituted argument pack directly.
3390 Deduced.reserve(TemplateParams->size());
3391 for (unsigned I = 0, N = ExplicitArgumentList->size(); I != N; ++I) {
3392 const TemplateArgument &Arg = ExplicitArgumentList->get(I);
3393 if (I == PartiallySubstitutedPackIndex)
3394 Deduced.push_back(DeducedTemplateArgument());
3395 else
3396 Deduced.push_back(Arg);
3397 }
3398
3399 return TDK_Success;
3400}
3401
3402/// Check whether the deduced argument type for a call to a function
3403/// template matches the actual argument type per C++ [temp.deduct.call]p4.
3404static Sema::TemplateDeductionResult
3405CheckOriginalCallArgDeduction(Sema &S, TemplateDeductionInfo &Info,
3406 Sema::OriginalCallArg OriginalArg,
3407 QualType DeducedA) {
3408 ASTContext &Context = S.Context;
3409
3410 auto Failed = [&]() -> Sema::TemplateDeductionResult {
3411 Info.FirstArg = TemplateArgument(DeducedA);
3412 Info.SecondArg = TemplateArgument(OriginalArg.OriginalArgType);
3413 Info.CallArgIndex = OriginalArg.ArgIdx;
3414 return OriginalArg.DecomposedParam ? Sema::TDK_DeducedMismatchNested
3415 : Sema::TDK_DeducedMismatch;
3416 };
3417
3418 QualType A = OriginalArg.OriginalArgType;
3419 QualType OriginalParamType = OriginalArg.OriginalParamType;
3420
3421 // Check for type equality (top-level cv-qualifiers are ignored).
3422 if (Context.hasSameUnqualifiedType(A, DeducedA))
3423 return Sema::TDK_Success;
3424
3425 // Strip off references on the argument types; they aren't needed for
3426 // the following checks.
3427 if (const ReferenceType *DeducedARef = DeducedA->getAs<ReferenceType>())
3428 DeducedA = DeducedARef->getPointeeType();
3429 if (const ReferenceType *ARef = A->getAs<ReferenceType>())
3430 A = ARef->getPointeeType();
3431
3432 // C++ [temp.deduct.call]p4:
3433 // [...] However, there are three cases that allow a difference:
3434 // - If the original P is a reference type, the deduced A (i.e., the
3435 // type referred to by the reference) can be more cv-qualified than
3436 // the transformed A.
3437 if (const ReferenceType *OriginalParamRef
3438 = OriginalParamType->getAs<ReferenceType>()) {
3439 // We don't want to keep the reference around any more.
3440 OriginalParamType = OriginalParamRef->getPointeeType();
3441
3442 // FIXME: Resolve core issue (no number yet): if the original P is a
3443 // reference type and the transformed A is function type "noexcept F",
3444 // the deduced A can be F.
3445 QualType Tmp;
3446 if (A->isFunctionType() && S.IsFunctionConversion(A, DeducedA, Tmp))
3447 return Sema::TDK_Success;
3448
3449 Qualifiers AQuals = A.getQualifiers();
3450 Qualifiers DeducedAQuals = DeducedA.getQualifiers();
3451
3452 // Under Objective-C++ ARC, the deduced type may have implicitly
3453 // been given strong or (when dealing with a const reference)
3454 // unsafe_unretained lifetime. If so, update the original
3455 // qualifiers to include this lifetime.
3456 if (S.getLangOpts().ObjCAutoRefCount &&
3457 ((DeducedAQuals.getObjCLifetime() == Qualifiers::OCL_Strong &&
3458 AQuals.getObjCLifetime() == Qualifiers::OCL_None) ||
3459 (DeducedAQuals.hasConst() &&
3460 DeducedAQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone))) {
3461 AQuals.setObjCLifetime(DeducedAQuals.getObjCLifetime());
3462 }
3463
3464 if (AQuals == DeducedAQuals) {
3465 // Qualifiers match; there's nothing to do.
3466 } else if (!DeducedAQuals.compatiblyIncludes(AQuals)) {
3467 return Failed();
3468 } else {
3469 // Qualifiers are compatible, so have the argument type adopt the
3470 // deduced argument type's qualifiers as if we had performed the
3471 // qualification conversion.
3472 A = Context.getQualifiedType(A.getUnqualifiedType(), DeducedAQuals);
3473 }
3474 }
3475
3476 // - The transformed A can be another pointer or pointer to member
3477 // type that can be converted to the deduced A via a function pointer
3478 // conversion and/or a qualification conversion.
3479 //
3480 // Also allow conversions which merely strip __attribute__((noreturn)) from
3481 // function types (recursively).
3482 bool ObjCLifetimeConversion = false;
3483 QualType ResultTy;
3484 if ((A->isAnyPointerType() || A->isMemberPointerType()) &&
3485 (S.IsQualificationConversion(A, DeducedA, false,
3486 ObjCLifetimeConversion) ||
3487 S.IsFunctionConversion(A, DeducedA, ResultTy)))
3488 return Sema::TDK_Success;
3489
3490 // - If P is a class and P has the form simple-template-id, then the
3491 // transformed A can be a derived class of the deduced A. [...]
3492 // [...] Likewise, if P is a pointer to a class of the form
3493 // simple-template-id, the transformed A can be a pointer to a
3494 // derived class pointed to by the deduced A.
3495 if (const PointerType *OriginalParamPtr
3496 = OriginalParamType->getAs<PointerType>()) {
3497 if (const PointerType *DeducedAPtr = DeducedA->getAs<PointerType>()) {
3498 if (const PointerType *APtr = A->getAs<PointerType>()) {
3499 if (A->getPointeeType()->isRecordType()) {
3500 OriginalParamType = OriginalParamPtr->getPointeeType();
3501 DeducedA = DeducedAPtr->getPointeeType();
3502 A = APtr->getPointeeType();
3503 }
3504 }
3505 }
3506 }
3507
3508 if (Context.hasSameUnqualifiedType(A, DeducedA))
3509 return Sema::TDK_Success;
3510
3511 if (A->isRecordType() && isSimpleTemplateIdType(OriginalParamType) &&
3512 S.IsDerivedFrom(Info.getLocation(), A, DeducedA))
3513 return Sema::TDK_Success;
3514
3515 return Failed();
3516}
3517
3518/// Find the pack index for a particular parameter index in an instantiation of
3519/// a function template with specific arguments.
3520///
3521/// \return The pack index for whichever pack produced this parameter, or -1
3522/// if this was not produced by a parameter. Intended to be used as the
3523/// ArgumentPackSubstitutionIndex for further substitutions.
3524// FIXME: We should track this in OriginalCallArgs so we don't need to
3525// reconstruct it here.
3526static unsigned getPackIndexForParam(Sema &S,
3527 FunctionTemplateDecl *FunctionTemplate,
3528 const MultiLevelTemplateArgumentList &Args,
3529 unsigned ParamIdx) {
3530 unsigned Idx = 0;
3531 for (auto *PD : FunctionTemplate->getTemplatedDecl()->parameters()) {
3532 if (PD->isParameterPack()) {
3533 unsigned NumExpansions =
3534 S.getNumArgumentsInExpansion(PD->getType(), Args).getValueOr(1);
3535 if (Idx + NumExpansions > ParamIdx)
3536 return ParamIdx - Idx;
3537 Idx += NumExpansions;
3538 } else {
3539 if (Idx == ParamIdx)
3540 return -1; // Not a pack expansion
3541 ++Idx;
3542 }
3543 }
3544
3545 llvm_unreachable("parameter index would not be produced from template")__builtin_unreachable();
3546}
3547
3548/// Finish template argument deduction for a function template,
3549/// checking the deduced template arguments for completeness and forming
3550/// the function template specialization.
3551///
3552/// \param OriginalCallArgs If non-NULL, the original call arguments against
3553/// which the deduced argument types should be compared.
3554Sema::TemplateDeductionResult Sema::FinishTemplateArgumentDeduction(
3555 FunctionTemplateDecl *FunctionTemplate,
3556 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
3557 unsigned NumExplicitlySpecified, FunctionDecl *&Specialization,
3558 TemplateDeductionInfo &Info,
3559 SmallVectorImpl<OriginalCallArg> const *OriginalCallArgs,
3560 bool PartialOverloading, llvm::function_ref<bool()> CheckNonDependent) {
3561 // Unevaluated SFINAE context.
3562 EnterExpressionEvaluationContext Unevaluated(
3563 *this, Sema::ExpressionEvaluationContext::Unevaluated);
3564 SFINAETrap Trap(*this);
3565
3566 // Enter a new template instantiation context while we instantiate the
3567 // actual function declaration.
3568 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end());
3569 InstantiatingTemplate Inst(
3570 *this, Info.getLocation(), FunctionTemplate, DeducedArgs,
3571 CodeSynthesisContext::DeducedTemplateArgumentSubstitution, Info);
3572 if (Inst.isInvalid())
3573 return TDK_InstantiationDepth;
3574
3575 ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl());
3576
3577 // C++ [temp.deduct.type]p2:
3578 // [...] or if any template argument remains neither deduced nor
3579 // explicitly specified, template argument deduction fails.
3580 SmallVector<TemplateArgument, 4> Builder;
3581 if (auto Result = ConvertDeducedTemplateArguments(
3582 *this, FunctionTemplate, /*IsDeduced*/true, Deduced, Info, Builder,
3583 CurrentInstantiationScope, NumExplicitlySpecified,
3584 PartialOverloading))
3585 return Result;
3586
3587 // C++ [temp.deduct.call]p10: [DR1391]
3588 // If deduction succeeds for all parameters that contain
3589 // template-parameters that participate in template argument deduction,
3590 // and all template arguments are explicitly specified, deduced, or
3591 // obtained from default template arguments, remaining parameters are then
3592 // compared with the corresponding arguments. For each remaining parameter
3593 // P with a type that was non-dependent before substitution of any
3594 // explicitly-specified template arguments, if the corresponding argument
3595 // A cannot be implicitly converted to P, deduction fails.
3596 if (CheckNonDependent())
3597 return TDK_NonDependentConversionFailure;
3598
3599 // Form the template argument list from the deduced template arguments.
3600 TemplateArgumentList *DeducedArgumentList
3601 = TemplateArgumentList::CreateCopy(Context, Builder);
3602 Info.reset(DeducedArgumentList);
3603
3604 // Substitute the deduced template arguments into the function template
3605 // declaration to produce the function template specialization.
3606 DeclContext *Owner = FunctionTemplate->getDeclContext();
3607 if (FunctionTemplate->getFriendObjectKind())
3608 Owner = FunctionTemplate->getLexicalDeclContext();
3609 MultiLevelTemplateArgumentList SubstArgs(*DeducedArgumentList);
3610 Specialization = cast_or_null<FunctionDecl>(
3611 SubstDecl(FunctionTemplate->getTemplatedDecl(), Owner, SubstArgs));
3612 if (!Specialization || Specialization->isInvalidDecl())
3613 return TDK_SubstitutionFailure;
3614
3615 assert(Specialization->getPrimaryTemplate()->getCanonicalDecl() ==(static_cast<void> (0))
3616 FunctionTemplate->getCanonicalDecl())(static_cast<void> (0));
3617
3618 // If the template argument list is owned by the function template
3619 // specialization, release it.
3620 if (Specialization->getTemplateSpecializationArgs() == DeducedArgumentList &&
3621 !Trap.hasErrorOccurred())
3622 Info.take();
3623
3624 // There may have been an error that did not prevent us from constructing a
3625 // declaration. Mark the declaration invalid and return with a substitution
3626 // failure.
3627 if (Trap.hasErrorOccurred()) {
3628 Specialization->setInvalidDecl(true);
3629 return TDK_SubstitutionFailure;
3630 }
3631
3632 // C++2a [temp.deduct]p5
3633 // [...] When all template arguments have been deduced [...] all uses of
3634 // template parameters [...] are replaced with the corresponding deduced
3635 // or default argument values.
3636 // [...] If the function template has associated constraints
3637 // ([temp.constr.decl]), those constraints are checked for satisfaction
3638 // ([temp.constr.constr]). If the constraints are not satisfied, type
3639 // deduction fails.
3640 if (!PartialOverloading ||
3641 (Builder.size() == FunctionTemplate->getTemplateParameters()->size())) {
3642 if (CheckInstantiatedFunctionTemplateConstraints(Info.getLocation(),
3643 Specialization, Builder, Info.AssociatedConstraintsSatisfaction))
3644 return TDK_MiscellaneousDeductionFailure;
3645
3646 if (!Info.AssociatedConstraintsSatisfaction.IsSatisfied) {
3647 Info.reset(TemplateArgumentList::CreateCopy(Context, Builder));
3648 return TDK_ConstraintsNotSatisfied;
3649 }
3650 }
3651
3652 if (OriginalCallArgs) {
3653 // C++ [temp.deduct.call]p4:
3654 // In general, the deduction process attempts to find template argument
3655 // values that will make the deduced A identical to A (after the type A
3656 // is transformed as described above). [...]
3657 llvm::SmallDenseMap<std::pair<unsigned, QualType>, QualType> DeducedATypes;
3658 for (unsigned I = 0, N = OriginalCallArgs->size(); I != N; ++I) {
3659 OriginalCallArg OriginalArg = (*OriginalCallArgs)[I];
3660
3661 auto ParamIdx = OriginalArg.ArgIdx;
3662 if (ParamIdx >= Specialization->getNumParams())
3663 // FIXME: This presumably means a pack ended up smaller than we
3664 // expected while deducing. Should this not result in deduction
3665 // failure? Can it even happen?
3666 continue;
3667
3668 QualType DeducedA;
3669 if (!OriginalArg.DecomposedParam) {
3670 // P is one of the function parameters, just look up its substituted
3671 // type.
3672 DeducedA = Specialization->getParamDecl(ParamIdx)->getType();
3673 } else {
3674 // P is a decomposed element of a parameter corresponding to a
3675 // braced-init-list argument. Substitute back into P to find the
3676 // deduced A.
3677 QualType &CacheEntry =
3678 DeducedATypes[{ParamIdx, OriginalArg.OriginalParamType}];
3679 if (CacheEntry.isNull()) {
3680 ArgumentPackSubstitutionIndexRAII PackIndex(
3681 *this, getPackIndexForParam(*this, FunctionTemplate, SubstArgs,
3682 ParamIdx));
3683 CacheEntry =
3684 SubstType(OriginalArg.OriginalParamType, SubstArgs,
3685 Specialization->getTypeSpecStartLoc(),
3686 Specialization->getDeclName());
3687 }
3688 DeducedA = CacheEntry;
3689 }
3690
3691 if (auto TDK =
3692 CheckOriginalCallArgDeduction(*this, Info, OriginalArg, DeducedA))
3693 return TDK;
3694 }
3695 }
3696
3697 // If we suppressed any diagnostics while performing template argument
3698 // deduction, and if we haven't already instantiated this declaration,
3699 // keep track of these diagnostics. They'll be emitted if this specialization
3700 // is actually used.
3701 if (Info.diag_begin() != Info.diag_end()) {
3702 SuppressedDiagnosticsMap::iterator
3703 Pos = SuppressedDiagnostics.find(Specialization->getCanonicalDecl());
3704 if (Pos == SuppressedDiagnostics.end())
3705 SuppressedDiagnostics[Specialization->getCanonicalDecl()]
3706 .append(Info.diag_begin(), Info.diag_end());
3707 }
3708
3709 return TDK_Success;
3710}
3711
3712/// Gets the type of a function for template-argument-deducton
3713/// purposes when it's considered as part of an overload set.
3714static QualType GetTypeOfFunction(Sema &S, const OverloadExpr::FindResult &R,
3715 FunctionDecl *Fn) {
3716 // We may need to deduce the return type of the function now.
3717 if (S.getLangOpts().CPlusPlus14 && Fn->getReturnType()->isUndeducedType() &&
3718 S.DeduceReturnType(Fn, R.Expression->getExprLoc(), /*Diagnose*/ false))
3719 return {};
3720
3721 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn))
3722 if (Method->isInstance()) {
3723 // An instance method that's referenced in a form that doesn't
3724 // look like a member pointer is just invalid.
3725 if (!R.HasFormOfMemberPointer)
3726 return {};
3727
3728 return S.Context.getMemberPointerType(Fn->getType(),
3729 S.Context.getTypeDeclType(Method->getParent()).getTypePtr());
3730 }
3731
3732 if (!R.IsAddressOfOperand) return Fn->getType();
3733 return S.Context.getPointerType(Fn->getType());
3734}
3735
3736/// Apply the deduction rules for overload sets.
3737///
3738/// \return the null type if this argument should be treated as an
3739/// undeduced context
3740static QualType
3741ResolveOverloadForDeduction(Sema &S, TemplateParameterList *TemplateParams,
3742 Expr *Arg, QualType ParamType,
3743 bool ParamWasReference) {
3744
3745 OverloadExpr::FindResult R = OverloadExpr::find(Arg);
3746
3747 OverloadExpr *Ovl = R.Expression;
3748
3749 // C++0x [temp.deduct.call]p4
3750 unsigned TDF = 0;
3751 if (ParamWasReference)
3752 TDF |= TDF_ParamWithReferenceType;
3753 if (R.IsAddressOfOperand)
3754 TDF |= TDF_IgnoreQualifiers;
3755
3756 // C++0x [temp.deduct.call]p6:
3757 // When P is a function type, pointer to function type, or pointer
3758 // to member function type:
3759
3760 if (!ParamType->isFunctionType() &&
3761 !ParamType->isFunctionPointerType() &&
3762 !ParamType->isMemberFunctionPointerType()) {
3763 if (Ovl->hasExplicitTemplateArgs()) {
3764 // But we can still look for an explicit specialization.
3765 if (FunctionDecl *ExplicitSpec
3766 = S.ResolveSingleFunctionTemplateSpecialization(Ovl))
3767 return GetTypeOfFunction(S, R, ExplicitSpec);
3768 }
3769
3770 DeclAccessPair DAP;
3771 if (FunctionDecl *Viable =
3772 S.resolveAddressOfSingleOverloadCandidate(Arg, DAP))
3773 return GetTypeOfFunction(S, R, Viable);
3774
3775 return {};
3776 }
3777
3778 // Gather the explicit template arguments, if any.
3779 TemplateArgumentListInfo ExplicitTemplateArgs;
3780 if (Ovl->hasExplicitTemplateArgs())
3781 Ovl->copyTemplateArgumentsInto(ExplicitTemplateArgs);
3782 QualType Match;
3783 for (UnresolvedSetIterator I = Ovl->decls_begin(),
3784 E = Ovl->decls_end(); I != E; ++I) {
3785 NamedDecl *D = (*I)->getUnderlyingDecl();
3786
3787 if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D)) {
3788 // - If the argument is an overload set containing one or more
3789 // function templates, the parameter is treated as a
3790 // non-deduced context.
3791 if (!Ovl->hasExplicitTemplateArgs())
3792 return {};
3793
3794 // Otherwise, see if we can resolve a function type
3795 FunctionDecl *Specialization = nullptr;
3796 TemplateDeductionInfo Info(Ovl->getNameLoc());
3797 if (S.DeduceTemplateArguments(FunTmpl, &ExplicitTemplateArgs,
3798 Specialization, Info))
3799 continue;
3800
3801 D = Specialization;
3802 }
3803
3804 FunctionDecl *Fn = cast<FunctionDecl>(D);
3805 QualType ArgType = GetTypeOfFunction(S, R, Fn);
3806 if (ArgType.isNull()) continue;
3807
3808 // Function-to-pointer conversion.
3809 if (!ParamWasReference && ParamType->isPointerType() &&
3810 ArgType->isFunctionType())
3811 ArgType = S.Context.getPointerType(ArgType);
3812
3813 // - If the argument is an overload set (not containing function
3814 // templates), trial argument deduction is attempted using each
3815 // of the members of the set. If deduction succeeds for only one
3816 // of the overload set members, that member is used as the
3817 // argument value for the deduction. If deduction succeeds for
3818 // more than one member of the overload set the parameter is
3819 // treated as a non-deduced context.
3820
3821 // We do all of this in a fresh context per C++0x [temp.deduct.type]p2:
3822 // Type deduction is done independently for each P/A pair, and
3823 // the deduced template argument values are then combined.
3824 // So we do not reject deductions which were made elsewhere.
3825 SmallVector<DeducedTemplateArgument, 8>
3826 Deduced(TemplateParams->size());
3827 TemplateDeductionInfo Info(Ovl->getNameLoc());
3828 Sema::TemplateDeductionResult Result
3829 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, ParamType,
3830 ArgType, Info, Deduced, TDF);
3831 if (Result) continue;
3832 if (!Match.isNull())
3833 return {};
3834 Match = ArgType;
3835 }
3836
3837 return Match;
3838}
3839
3840/// Perform the adjustments to the parameter and argument types
3841/// described in C++ [temp.deduct.call].
3842///
3843/// \returns true if the caller should not attempt to perform any template
3844/// argument deduction based on this P/A pair because the argument is an
3845/// overloaded function set that could not be resolved.
3846static bool AdjustFunctionParmAndArgTypesForDeduction(
3847 Sema &S, TemplateParameterList *TemplateParams, unsigned FirstInnerIndex,
3848 QualType &ParamType, QualType &ArgType, Expr *Arg, unsigned &TDF) {
3849 // C++0x [temp.deduct.call]p3:
3850 // If P is a cv-qualified type, the top level cv-qualifiers of P's type
3851 // are ignored for type deduction.
3852 if (ParamType.hasQualifiers())
3853 ParamType = ParamType.getUnqualifiedType();
3854
3855 // [...] If P is a reference type, the type referred to by P is
3856 // used for type deduction.
3857 const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>();
3858 if (ParamRefType)
3859 ParamType = ParamRefType->getPointeeType();
3860
3861 // Overload sets usually make this parameter an undeduced context,
3862 // but there are sometimes special circumstances. Typically
3863 // involving a template-id-expr.
3864 if (ArgType == S.Context.OverloadTy) {
3865 ArgType = ResolveOverloadForDeduction(S, TemplateParams,
3866 Arg, ParamType,
3867 ParamRefType != nullptr);
3868 if (ArgType.isNull())
3869 return true;
3870 }
3871
3872 if (ParamRefType) {
3873 // If the argument has incomplete array type, try to complete its type.
3874 if (ArgType->isIncompleteArrayType())
3875 ArgType = S.getCompletedType(Arg);
3876
3877 // C++1z [temp.deduct.call]p3:
3878 // If P is a forwarding reference and the argument is an lvalue, the type
3879 // "lvalue reference to A" is used in place of A for type deduction.
3880 if (isForwardingReference(QualType(ParamRefType, 0), FirstInnerIndex) &&
3881 Arg->isLValue()) {
3882 if (S.getLangOpts().OpenCL && !ArgType.hasAddressSpace())
3883 ArgType = S.Context.getAddrSpaceQualType(ArgType, LangAS::opencl_generic);
3884 ArgType = S.Context.getLValueReferenceType(ArgType);
3885 }
3886 } else {
3887 // C++ [temp.deduct.call]p2:
3888 // If P is not a reference type:
3889 // - If A is an array type, the pointer type produced by the
3890 // array-to-pointer standard conversion (4.2) is used in place of
3891 // A for type deduction; otherwise,
3892 if (ArgType->isArrayType())
3893 ArgType = S.Context.getArrayDecayedType(ArgType);
3894 // - If A is a function type, the pointer type produced by the
3895 // function-to-pointer standard conversion (4.3) is used in place
3896 // of A for type deduction; otherwise,
3897 else if (ArgType->isFunctionType())
3898 ArgType = S.Context.getPointerType(ArgType);
3899 else {
3900 // - If A is a cv-qualified type, the top level cv-qualifiers of A's
3901 // type are ignored for type deduction.
3902 ArgType = ArgType.getUnqualifiedType();
3903 }
3904 }
3905
3906 // C++0x [temp.deduct.call]p4:
3907 // In general, the deduction process attempts to find template argument
3908 // values that will make the deduced A identical to A (after the type A
3909 // is transformed as described above). [...]
3910 TDF = TDF_SkipNonDependent;
3911
3912 // - If the original P is a reference type, the deduced A (i.e., the
3913 // type referred to by the reference) can be more cv-qualified than
3914 // the transformed A.
3915 if (ParamRefType)
3916 TDF |= TDF_ParamWithReferenceType;
3917 // - The transformed A can be another pointer or pointer to member
3918 // type that can be converted to the deduced A via a qualification
3919 // conversion (4.4).
3920 if (ArgType->isPointerType() || ArgType->isMemberPointerType() ||
3921 ArgType->isObjCObjectPointerType())
3922 TDF |= TDF_IgnoreQualifiers;
3923 // - If P is a class and P has the form simple-template-id, then the
3924 // transformed A can be a derived class of the deduced A. Likewise,
3925 // if P is a pointer to a class of the form simple-template-id, the
3926 // transformed A can be a pointer to a derived class pointed to by
3927 // the deduced A.
3928 if (isSimpleTemplateIdType(ParamType) ||
3929 (isa<PointerType>(ParamType) &&
3930 isSimpleTemplateIdType(
3931 ParamType->castAs<PointerType>()->getPointeeType())))
3932 TDF |= TDF_DerivedClass;
3933
3934 return false;
3935}
3936
3937static bool
3938hasDeducibleTemplateParameters(Sema &S, FunctionTemplateDecl *FunctionTemplate,
3939 QualType T);
3940
3941static Sema::TemplateDeductionResult DeduceTemplateArgumentsFromCallArgument(
3942 Sema &S, TemplateParameterList *TemplateParams, unsigned FirstInnerIndex,
3943 QualType ParamType, Expr *Arg, TemplateDeductionInfo &Info,
3944 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
3945 SmallVectorImpl<Sema::OriginalCallArg> &OriginalCallArgs,
3946 bool DecomposedParam, unsigned ArgIdx, unsigned TDF);
3947
3948/// Attempt template argument deduction from an initializer list
3949/// deemed to be an argument in a function call.
3950static Sema::TemplateDeductionResult DeduceFromInitializerList(
3951 Sema &S, TemplateParameterList *TemplateParams, QualType AdjustedParamType,
3952 InitListExpr *ILE, TemplateDeductionInfo &Info,
3953 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
3954 SmallVectorImpl<Sema::OriginalCallArg> &OriginalCallArgs, unsigned ArgIdx,
3955 unsigned TDF) {
3956 // C++ [temp.deduct.call]p1: (CWG 1591)
3957 // If removing references and cv-qualifiers from P gives
3958 // std::initializer_list<P0> or P0[N] for some P0 and N and the argument is
3959 // a non-empty initializer list, then deduction is performed instead for
3960 // each element of the initializer list, taking P0 as a function template
3961 // parameter type and the initializer element as its argument
3962 //
3963 // We've already removed references and cv-qualifiers here.
3964 if (!ILE->getNumInits())
3965 return Sema::TDK_Success;
3966
3967 QualType ElTy;
3968 auto *ArrTy = S.Context.getAsArrayType(AdjustedParamType);
3969 if (ArrTy)
3970 ElTy = ArrTy->getElementType();
3971 else if (!S.isStdInitializerList(AdjustedParamType, &ElTy)) {
3972 // Otherwise, an initializer list argument causes the parameter to be
3973 // considered a non-deduced context
3974 return Sema::TDK_Success;
3975 }
3976
3977 // Resolving a core issue: a braced-init-list containing any designators is
3978 // a non-deduced context.
3979 for (Expr *E : ILE->inits())
3980 if (isa<DesignatedInitExpr>(E))
3981 return Sema::TDK_Success;
3982
3983 // Deduction only needs to be done for dependent types.
3984 if (ElTy->isDependentType()) {
3985 for (Expr *E : ILE->inits()) {
3986 if (auto Result = DeduceTemplateArgumentsFromCallArgument(
3987 S, TemplateParams, 0, ElTy, E, Info, Deduced, OriginalCallArgs, true,
3988 ArgIdx, TDF))
3989 return Result;
3990 }
3991 }
3992
3993 // in the P0[N] case, if N is a non-type template parameter, N is deduced
3994 // from the length of the initializer list.
3995 if (auto *DependentArrTy = dyn_cast_or_null<DependentSizedArrayType>(ArrTy)) {
3996 // Determine the array bound is something we can deduce.
3997 if (const NonTypeTemplateParmDecl *NTTP =
3998 getDeducedParameterFromExpr(Info, DependentArrTy->getSizeExpr())) {
3999 // We can perform template argument deduction for the given non-type
4000 // template parameter.
4001 // C++ [temp.deduct.type]p13:
4002 // The type of N in the type T[N] is std::size_t.
4003 QualType T = S.Context.getSizeType();
4004 llvm::APInt Size(S.Context.getIntWidth(T), ILE->getNumInits());
4005 if (auto Result = DeduceNonTypeTemplateArgument(
4006 S, TemplateParams, NTTP, llvm::APSInt(Size), T,
4007 /*ArrayBound=*/true, Info, Deduced))
4008 return Result;
4009 }
4010 }
4011
4012 return Sema::TDK_Success;
4013}
4014
4015/// Perform template argument deduction per [temp.deduct.call] for a
4016/// single parameter / argument pair.
4017static Sema::TemplateDeductionResult DeduceTemplateArgumentsFromCallArgument(
4018 Sema &S, TemplateParameterList *TemplateParams, unsigned FirstInnerIndex,
4019 QualType ParamType, Expr *Arg, TemplateDeductionInfo &Info,
4020 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
4021 SmallVectorImpl<Sema::OriginalCallArg> &OriginalCallArgs,
4022 bool DecomposedParam, unsigned ArgIdx, unsigned TDF) {
4023 QualType ArgType = Arg->getType();
4024 QualType OrigParamType = ParamType;
4025
4026 // If P is a reference type [...]
4027 // If P is a cv-qualified type [...]
4028 if (AdjustFunctionParmAndArgTypesForDeduction(
4029 S, TemplateParams, FirstInnerIndex, ParamType, ArgType, Arg, TDF))
4030 return Sema::TDK_Success;
4031
4032 // If [...] the argument is a non-empty initializer list [...]
4033 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Arg))
4034 return DeduceFromInitializerList(S, TemplateParams, ParamType, ILE, Info,
4035 Deduced, OriginalCallArgs, ArgIdx, TDF);
4036
4037 // [...] the deduction process attempts to find template argument values
4038 // that will make the deduced A identical to A
4039 //
4040 // Keep track of the argument type and corresponding parameter index,
4041 // so we can check for compatibility between the deduced A and A.
4042 OriginalCallArgs.push_back(
4043 Sema::OriginalCallArg(OrigParamType, DecomposedParam, ArgIdx, ArgType));
4044 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, ParamType,
4045 ArgType, Info, Deduced, TDF);
4046}
4047
4048/// Perform template argument deduction from a function call
4049/// (C++ [temp.deduct.call]).
4050///
4051/// \param FunctionTemplate the function template for which we are performing
4052/// template argument deduction.
4053///
4054/// \param ExplicitTemplateArgs the explicit template arguments provided
4055/// for this call.
4056///
4057/// \param Args the function call arguments
4058///
4059/// \param Specialization if template argument deduction was successful,
4060/// this will be set to the function template specialization produced by
4061/// template argument deduction.
4062///
4063/// \param Info the argument will be updated to provide additional information
4064/// about template argument deduction.
4065///
4066/// \param CheckNonDependent A callback to invoke to check conversions for
4067/// non-dependent parameters, between deduction and substitution, per DR1391.
4068/// If this returns true, substitution will be skipped and we return
4069/// TDK_NonDependentConversionFailure. The callback is passed the parameter
4070/// types (after substituting explicit template arguments).
4071///
4072/// \returns the result of template argument deduction.
4073Sema::TemplateDeductionResult Sema::DeduceTemplateArguments(
4074 FunctionTemplateDecl *FunctionTemplate,
4075 TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
4076 FunctionDecl *&Specialization, TemplateDeductionInfo &Info,
4077 bool PartialOverloading,
4078 llvm::function_ref<bool(ArrayRef<QualType>)> CheckNonDependent) {
4079 if (FunctionTemplate->isInvalidDecl())
4080 return TDK_Invalid;
4081
4082 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
4083 unsigned NumParams = Function->getNumParams();
4084
4085 unsigned FirstInnerIndex = getFirstInnerIndex(FunctionTemplate);
4086
4087 // C++ [temp.deduct.call]p1:
4088 // Template argument deduction is done by comparing each function template
4089 // parameter type (call it P) with the type of the corresponding argument
4090 // of the call (call it A) as described below.
4091 if (Args.size() < Function->getMinRequiredArguments() && !PartialOverloading)
4092 return TDK_TooFewArguments;
4093 else if (TooManyArguments(NumParams, Args.size(), PartialOverloading)) {
4094 const auto *Proto = Function->getType()->castAs<FunctionProtoType>();
4095 if (Proto->isTemplateVariadic())
4096 /* Do nothing */;
4097 else if (!Proto->isVariadic())
4098 return TDK_TooManyArguments;
4099 }
4100
4101 // The types of the parameters from which we will perform template argument
4102 // deduction.
4103 LocalInstantiationScope InstScope(*this);
4104 TemplateParameterList *TemplateParams
4105 = FunctionTemplate->getTemplateParameters();
4106 SmallVector<DeducedTemplateArgument, 4> Deduced;
4107 SmallVector<QualType, 8> ParamTypes;
4108 unsigned NumExplicitlySpecified = 0;
4109 if (ExplicitTemplateArgs) {
4110 TemplateDeductionResult Result;
4111 runWithSufficientStackSpace(Info.getLocation(), [&] {
4112 Result = SubstituteExplicitTemplateArguments(
4113 FunctionTemplate, *ExplicitTemplateArgs, Deduced, ParamTypes, nullptr,
4114 Info);
4115 });
4116 if (Result)
4117 return Result;
4118
4119 NumExplicitlySpecified = Deduced.size();
4120 } else {
4121 // Just fill in the parameter types from the function declaration.
4122 for (unsigned I = 0; I != NumParams; ++I)
4123 ParamTypes.push_back(Function->getParamDecl(I)->getType());
4124 }
4125
4126 SmallVector<OriginalCallArg, 8> OriginalCallArgs;
4127
4128 // Deduce an argument of type ParamType from an expression with index ArgIdx.
4129 auto DeduceCallArgument = [&](QualType ParamType, unsigned ArgIdx) {
4130 // C++ [demp.deduct.call]p1: (DR1391)
4131 // Template argument deduction is done by comparing each function template
4132 // parameter that contains template-parameters that participate in
4133 // template argument deduction ...
4134 if (!hasDeducibleTemplateParameters(*this, FunctionTemplate, ParamType))
4135 return Sema::TDK_Success;
4136
4137 // ... with the type of the corresponding argument
4138 return DeduceTemplateArgumentsFromCallArgument(
4139 *this, TemplateParams, FirstInnerIndex, ParamType, Args[ArgIdx], Info, Deduced,
4140 OriginalCallArgs, /*Decomposed*/false, ArgIdx, /*TDF*/ 0);
4141 };
4142
4143 // Deduce template arguments from the function parameters.
4144 Deduced.resize(TemplateParams->size());
4145 SmallVector<QualType, 8> ParamTypesForArgChecking;
4146 for (unsigned ParamIdx = 0, NumParamTypes = ParamTypes.size(), ArgIdx = 0;
4147 ParamIdx != NumParamTypes; ++ParamIdx) {
4148 QualType ParamType = ParamTypes[ParamIdx];
4149
4150 const PackExpansionType *ParamExpansion =
4151 dyn_cast<PackExpansionType>(ParamType);
4152 if (!ParamExpansion) {
4153 // Simple case: matching a function parameter to a function argument.
4154 if (ArgIdx >= Args.size())
4155 break;
4156
4157 ParamTypesForArgChecking.push_back(ParamType);
4158 if (auto Result = DeduceCallArgument(ParamType, ArgIdx++))
4159 return Result;
4160
4161 continue;
4162 }
4163
4164 QualType ParamPattern = ParamExpansion->getPattern();
4165 PackDeductionScope PackScope(*this, TemplateParams, Deduced, Info,
4166 ParamPattern);
4167
4168 // C++0x [temp.deduct.call]p1:
4169 // For a function parameter pack that occurs at the end of the
4170 // parameter-declaration-list, the type A of each remaining argument of
4171 // the call is compared with the type P of the declarator-id of the
4172 // function parameter pack. Each comparison deduces template arguments
4173 // for subsequent positions in the template parameter packs expanded by
4174 // the function parameter pack. When a function parameter pack appears
4175 // in a non-deduced context [not at the end of the list], the type of
4176 // that parameter pack is never deduced.
4177 //
4178 // FIXME: The above rule allows the size of the parameter pack to change
4179 // after we skip it (in the non-deduced case). That makes no sense, so
4180 // we instead notionally deduce the pack against N arguments, where N is
4181 // the length of the explicitly-specified pack if it's expanded by the
4182 // parameter pack and 0 otherwise, and we treat each deduction as a
4183 // non-deduced context.
4184 if (ParamIdx + 1 == NumParamTypes || PackScope.hasFixedArity()) {
4185 for (; ArgIdx < Args.size() && PackScope.hasNextElement();
4186 PackScope.nextPackElement(), ++ArgIdx) {
4187 ParamTypesForArgChecking.push_back(ParamPattern);
4188 if (auto Result = DeduceCallArgument(ParamPattern, ArgIdx))
4189 return Result;
4190 }
4191 } else {
4192 // If the parameter type contains an explicitly-specified pack that we
4193 // could not expand, skip the number of parameters notionally created
4194 // by the expansion.
4195 Optional<unsigned> NumExpansions = ParamExpansion->getNumExpansions();
4196 if (NumExpansions && !PackScope.isPartiallyExpanded()) {
4197 for (unsigned I = 0; I != *NumExpansions && ArgIdx < Args.size();
4198 ++I, ++ArgIdx) {
4199 ParamTypesForArgChecking.push_back(ParamPattern);
4200 // FIXME: Should we add OriginalCallArgs for these? What if the
4201 // corresponding argument is a list?
4202 PackScope.nextPackElement();
4203 }
4204 }
4205 }
4206
4207 // Build argument packs for each of the parameter packs expanded by this
4208 // pack expansion.
4209 if (auto Result = PackScope.finish())
4210 return Result;
4211 }
4212
4213 // Capture the context in which the function call is made. This is the context
4214 // that is needed when the accessibility of template arguments is checked.
4215 DeclContext *CallingCtx = CurContext;
4216
4217 TemplateDeductionResult Result;
4218 runWithSufficientStackSpace(Info.getLocation(), [&] {
4219 Result = FinishTemplateArgumentDeduction(
4220 FunctionTemplate, Deduced, NumExplicitlySpecified, Specialization, Info,
4221 &OriginalCallArgs, PartialOverloading, [&, CallingCtx]() {
4222 ContextRAII SavedContext(*this, CallingCtx);
4223 return CheckNonDependent(ParamTypesForArgChecking);
4224 });
4225 });
4226 return Result;
4227}
4228
4229QualType Sema::adjustCCAndNoReturn(QualType ArgFunctionType,
4230 QualType FunctionType,
4231 bool AdjustExceptionSpec) {
4232 if (ArgFunctionType.isNull())
4233 return ArgFunctionType;
4234
4235 const auto *FunctionTypeP = FunctionType->castAs<FunctionProtoType>();
4236 const auto *ArgFunctionTypeP = ArgFunctionType->castAs<FunctionProtoType>();
4237 FunctionProtoType::ExtProtoInfo EPI = ArgFunctionTypeP->getExtProtoInfo();
4238 bool Rebuild = false;
4239
4240 CallingConv CC = FunctionTypeP->getCallConv();
4241 if (EPI.ExtInfo.getCC() != CC) {
4242 EPI.ExtInfo = EPI.ExtInfo.withCallingConv(CC);
4243 Rebuild = true;
4244 }
4245
4246 bool NoReturn = FunctionTypeP->getNoReturnAttr();
4247 if (EPI.ExtInfo.getNoReturn() != NoReturn) {
4248 EPI.ExtInfo = EPI.ExtInfo.withNoReturn(NoReturn);
4249 Rebuild = true;
4250 }
4251
4252 if (AdjustExceptionSpec && (FunctionTypeP->hasExceptionSpec() ||
4253 ArgFunctionTypeP->hasExceptionSpec())) {
4254 EPI.ExceptionSpec = FunctionTypeP->getExtProtoInfo().ExceptionSpec;
4255 Rebuild = true;
4256 }
4257
4258 if (!Rebuild)
4259 return ArgFunctionType;
4260
4261 return Context.getFunctionType(ArgFunctionTypeP->getReturnType(),
4262 ArgFunctionTypeP->getParamTypes(), EPI);
4263}
4264
4265/// Deduce template arguments when taking the address of a function
4266/// template (C++ [temp.deduct.funcaddr]) or matching a specialization to
4267/// a template.
4268///
4269/// \param FunctionTemplate the function template for which we are performing
4270/// template argument deduction.
4271///
4272/// \param ExplicitTemplateArgs the explicitly-specified template
4273/// arguments.
4274///
4275/// \param ArgFunctionType the function type that will be used as the
4276/// "argument" type (A) when performing template argument deduction from the
4277/// function template's function type. This type may be NULL, if there is no
4278/// argument type to compare against, in C++0x [temp.arg.explicit]p3.
4279///
4280/// \param Specialization if template argument deduction was successful,
4281/// this will be set to the function template specialization produced by
4282/// template argument deduction.
4283///
4284/// \param Info the argument will be updated to provide additional information
4285/// about template argument deduction.
4286///
4287/// \param IsAddressOfFunction If \c true, we are deducing as part of taking
4288/// the address of a function template per [temp.deduct.funcaddr] and
4289/// [over.over]. If \c false, we are looking up a function template
4290/// specialization based on its signature, per [temp.deduct.decl].
4291///
4292/// \returns the result of template argument deduction.
4293Sema::TemplateDeductionResult Sema::DeduceTemplateArguments(
4294 FunctionTemplateDecl *FunctionTemplate,
4295 TemplateArgumentListInfo *ExplicitTemplateArgs, QualType ArgFunctionType,
4296 FunctionDecl *&Specialization, TemplateDeductionInfo &Info,
4297 bool IsAddressOfFunction) {
4298 if (FunctionTemplate->isInvalidDecl())
4299 return TDK_Invalid;
4300
4301 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
4302 TemplateParameterList *TemplateParams
4303 = FunctionTemplate->getTemplateParameters();
4304 QualType FunctionType = Function->getType();
4305
4306 // Substitute any explicit template arguments.
4307 LocalInstantiationScope InstScope(*this);
4308 SmallVector<DeducedTemplateArgument, 4> Deduced;
4309 unsigned NumExplicitlySpecified = 0;
4310 SmallVector<QualType, 4> ParamTypes;
4311 if (ExplicitTemplateArgs) {
4312 TemplateDeductionResult Result;
4313 runWithSufficientStackSpace(Info.getLocation(), [&] {
4314 Result = SubstituteExplicitTemplateArguments(
1
Calling 'Sema::SubstituteExplicitTemplateArguments'
4315 FunctionTemplate, *ExplicitTemplateArgs, Deduced, ParamTypes,
4316 &FunctionType, Info);
4317 });
4318 if (Result)
4319 return Result;
4320
4321 NumExplicitlySpecified = Deduced.size();
4322 }
4323
4324 // When taking the address of a function, we require convertibility of
4325 // the resulting function type. Otherwise, we allow arbitrary mismatches
4326 // of calling convention and noreturn.
4327 if (!IsAddressOfFunction)
4328 ArgFunctionType = adjustCCAndNoReturn(ArgFunctionType, FunctionType,
4329 /*AdjustExceptionSpec*/false);
4330
4331 // Unevaluated SFINAE context.
4332 EnterExpressionEvaluationContext Unevaluated(
4333 *this, Sema::ExpressionEvaluationContext::Unevaluated);
4334 SFINAETrap Trap(*this);
4335
4336 Deduced.resize(TemplateParams->size());
4337
4338 // If the function has a deduced return type, substitute it for a dependent
4339 // type so that we treat it as a non-deduced context in what follows. If we
4340 // are looking up by signature, the signature type should also have a deduced
4341 // return type, which we instead expect to exactly match.
4342 bool HasDeducedReturnType = false;
4343 if (getLangOpts().CPlusPlus14 && IsAddressOfFunction &&
4344 Function->getReturnType()->getContainedAutoType()) {
4345 FunctionType = SubstAutoType(FunctionType, Context.DependentTy);
4346 HasDeducedReturnType = true;
4347 }
4348
4349 if (!ArgFunctionType.isNull() && !FunctionType.isNull()) {
4350 unsigned TDF =
4351 TDF_TopLevelParameterTypeList | TDF_AllowCompatibleFunctionType;
4352 // Deduce template arguments from the function type.
4353 if (TemplateDeductionResult Result
4354 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams,
4355 FunctionType, ArgFunctionType,
4356 Info, Deduced, TDF))
4357 return Result;
4358 }
4359
4360 TemplateDeductionResult Result;
4361 runWithSufficientStackSpace(Info.getLocation(), [&] {
4362 Result = FinishTemplateArgumentDeduction(FunctionTemplate, Deduced,
4363 NumExplicitlySpecified,
4364 Specialization, Info);
4365 });
4366 if (Result)
4367 return Result;
4368
4369 // If the function has a deduced return type, deduce it now, so we can check
4370 // that the deduced function type matches the requested type.
4371 if (HasDeducedReturnType &&
4372 Specialization->getReturnType()->isUndeducedType() &&
4373 DeduceReturnType(Specialization, Info.getLocation(), false))
4374 return TDK_MiscellaneousDeductionFailure;
4375
4376 // If the function has a dependent exception specification, resolve it now,
4377 // so we can check that the exception specification matches.
4378 auto *SpecializationFPT =
4379 Specialization->getType()->castAs<FunctionProtoType>();
4380 if (getLangOpts().CPlusPlus17 &&
4381 isUnresolvedExceptionSpec(SpecializationFPT->getExceptionSpecType()) &&
4382 !ResolveExceptionSpec(Info.getLocation(), SpecializationFPT))
4383 return TDK_MiscellaneousDeductionFailure;
4384
4385 // Adjust the exception specification of the argument to match the
4386 // substituted and resolved type we just formed. (Calling convention and
4387 // noreturn can't be dependent, so we don't actually need this for them
4388 // right now.)
4389 QualType SpecializationType = Specialization->getType();
4390 if (!IsAddressOfFunction)
4391 ArgFunctionType = adjustCCAndNoReturn(ArgFunctionType, SpecializationType,
4392 /*AdjustExceptionSpec*/true);
4393
4394 // If the requested function type does not match the actual type of the
4395 // specialization with respect to arguments of compatible pointer to function
4396 // types, template argument deduction fails.
4397 if (!ArgFunctionType.isNull()) {
4398 if (IsAddressOfFunction &&
4399 !isSameOrCompatibleFunctionType(
4400 Context.getCanonicalType(SpecializationType),
4401 Context.getCanonicalType(ArgFunctionType)))
4402 return TDK_MiscellaneousDeductionFailure;
4403
4404 if (!IsAddressOfFunction &&
4405 !Context.hasSameType(SpecializationType, ArgFunctionType))
4406 return TDK_MiscellaneousDeductionFailure;
4407 }
4408
4409 return TDK_Success;
4410}
4411
4412/// Deduce template arguments for a templated conversion
4413/// function (C++ [temp.deduct.conv]) and, if successful, produce a
4414/// conversion function template specialization.
4415Sema::TemplateDeductionResult
4416Sema::DeduceTemplateArguments(FunctionTemplateDecl *ConversionTemplate,
4417 QualType ToType,
4418 CXXConversionDecl *&Specialization,
4419 TemplateDeductionInfo &Info) {
4420 if (ConversionTemplate->isInvalidDecl())
4421 return TDK_Invalid;
4422
4423 CXXConversionDecl *ConversionGeneric
4424 = cast<CXXConversionDecl>(ConversionTemplate->getTemplatedDecl());
4425
4426 QualType FromType = ConversionGeneric->getConversionType();
4427
4428 // Canonicalize the types for deduction.
4429 QualType P = Context.getCanonicalType(FromType);
4430 QualType A = Context.getCanonicalType(ToType);
4431
4432 // C++0x [temp.deduct.conv]p2:
4433 // If P is a reference type, the type referred to by P is used for
4434 // type deduction.
4435 if (const ReferenceType *PRef = P->getAs<ReferenceType>())
4436 P = PRef->getPointeeType();
4437
4438 // C++0x [temp.deduct.conv]p4:
4439 // [...] If A is a reference type, the type referred to by A is used
4440 // for type deduction.
4441 if (const ReferenceType *ARef = A->getAs<ReferenceType>()) {
4442 A = ARef->getPointeeType();
4443 // We work around a defect in the standard here: cv-qualifiers are also
4444 // removed from P and A in this case, unless P was a reference type. This
4445 // seems to mostly match what other compilers are doing.
4446 if (!FromType->getAs<ReferenceType>()) {
4447 A = A.getUnqualifiedType();
4448 P = P.getUnqualifiedType();
4449 }
4450
4451 // C++ [temp.deduct.conv]p3:
4452 //
4453 // If A is not a reference type:
4454 } else {
4455 assert(!A->isReferenceType() && "Reference types were handled above")(static_cast<void> (0));
4456
4457 // - If P is an array type, the pointer type produced by the
4458 // array-to-pointer standard conversion (4.2) is used in place
4459 // of P for type deduction; otherwise,
4460 if (P->isArrayType())
4461 P = Context.getArrayDecayedType(P);
4462 // - If P is a function type, the pointer type produced by the
4463 // function-to-pointer standard conversion (4.3) is used in
4464 // place of P for type deduction; otherwise,
4465 else if (P->isFunctionType())
4466 P = Context.getPointerType(P);
4467 // - If P is a cv-qualified type, the top level cv-qualifiers of
4468 // P's type are ignored for type deduction.
4469 else
4470 P = P.getUnqualifiedType();
4471
4472 // C++0x [temp.deduct.conv]p4:
4473 // If A is a cv-qualified type, the top level cv-qualifiers of A's
4474 // type are ignored for type deduction. If A is a reference type, the type
4475 // referred to by A is used for type deduction.
4476 A = A.getUnqualifiedType();
4477 }
4478
4479 // Unevaluated SFINAE context.
4480 EnterExpressionEvaluationContext Unevaluated(
4481 *this, Sema::ExpressionEvaluationContext::Unevaluated);
4482 SFINAETrap Trap(*this);
4483
4484 // C++ [temp.deduct.conv]p1:
4485 // Template argument deduction is done by comparing the return
4486 // type of the template conversion function (call it P) with the
4487 // type that is required as the result of the conversion (call it
4488 // A) as described in 14.8.2.4.
4489 TemplateParameterList *TemplateParams
4490 = ConversionTemplate->getTemplateParameters();
4491 SmallVector<DeducedTemplateArgument, 4> Deduced;
4492 Deduced.resize(TemplateParams->size());
4493
4494 // C++0x [temp.deduct.conv]p4:
4495 // In general, the deduction process attempts to find template
4496 // argument values that will make the deduced A identical to
4497 // A. However, there are two cases that allow a difference:
4498 unsigned TDF = 0;
4499 // - If the original A is a reference type, A can be more
4500 // cv-qualified than the deduced A (i.e., the type referred to
4501 // by the reference)
4502 if (ToType->isReferenceType())
4503 TDF |= TDF_ArgWithReferenceType;
4504 // - The deduced A can be another pointer or pointer to member
4505 // type that can be converted to A via a qualification
4506 // conversion.
4507 //
4508 // (C++0x [temp.deduct.conv]p6 clarifies that this only happens when
4509 // both P and A are pointers or member pointers. In this case, we
4510 // just ignore cv-qualifiers completely).
4511 if ((P->isPointerType() && A->isPointerType()) ||
4512 (P->isMemberPointerType() && A->isMemberPointerType()))
4513 TDF |= TDF_IgnoreQualifiers;
4514 if (TemplateDeductionResult Result
4515 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams,
4516 P, A, Info, Deduced, TDF))
4517 return Result;
4518
4519 // Create an Instantiation Scope for finalizing the operator.
4520 LocalInstantiationScope InstScope(*this);
4521 // Finish template argument deduction.
4522 FunctionDecl *ConversionSpecialized = nullptr;
4523 TemplateDeductionResult Result;
4524 runWithSufficientStackSpace(Info.getLocation(), [&] {
4525 Result = FinishTemplateArgumentDeduction(ConversionTemplate, Deduced, 0,
4526 ConversionSpecialized, Info);
4527 });
4528 Specialization = cast_or_null<CXXConversionDecl>(ConversionSpecialized);
4529 return Result;
4530}
4531
4532/// Deduce template arguments for a function template when there is
4533/// nothing to deduce against (C++0x [temp.arg.explicit]p3).
4534///
4535/// \param FunctionTemplate the function template for which we are performing
4536/// template argument deduction.
4537///
4538/// \param ExplicitTemplateArgs the explicitly-specified template
4539/// arguments.
4540///
4541/// \param Specialization if template argument deduction was successful,
4542/// this will be set to the function template specialization produced by
4543/// template argument deduction.
4544///
4545/// \param Info the argument will be updated to provide additional information
4546/// about template argument deduction.
4547///
4548/// \param IsAddressOfFunction If \c true, we are deducing as part of taking
4549/// the address of a function template in a context where we do not have a
4550/// target type, per [over.over]. If \c false, we are looking up a function
4551/// template specialization based on its signature, which only happens when
4552/// deducing a function parameter type from an argument that is a template-id
4553/// naming a function template specialization.
4554///
4555/// \returns the result of template argument deduction.
4556Sema::TemplateDeductionResult Sema::DeduceTemplateArguments(
4557 FunctionTemplateDecl *FunctionTemplate,
4558 TemplateArgumentListInfo *ExplicitTemplateArgs,
4559 FunctionDecl *&Specialization, TemplateDeductionInfo &Info,
4560 bool IsAddressOfFunction) {
4561 return DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs,
4562 QualType(), Specialization, Info,
4563 IsAddressOfFunction);
4564}
4565
4566namespace {
4567 struct DependentAuto { bool IsPack; };
4568
4569 /// Substitute the 'auto' specifier or deduced template specialization type
4570 /// specifier within a type for a given replacement type.
4571 class SubstituteDeducedTypeTransform :
4572 public TreeTransform<SubstituteDeducedTypeTransform> {
4573 QualType Replacement;
4574 bool ReplacementIsPack;
4575 bool UseTypeSugar;
4576
4577 public:
4578 SubstituteDeducedTypeTransform(Sema &SemaRef, DependentAuto DA)
4579 : TreeTransform<SubstituteDeducedTypeTransform>(SemaRef), Replacement(),
4580 ReplacementIsPack(DA.IsPack), UseTypeSugar(true) {}
4581
4582 SubstituteDeducedTypeTransform(Sema &SemaRef, QualType Replacement,
4583 bool UseTypeSugar = true)
4584 : TreeTransform<SubstituteDeducedTypeTransform>(SemaRef),
4585 Replacement(Replacement), ReplacementIsPack(false),
4586 UseTypeSugar(UseTypeSugar) {}
4587
4588 QualType TransformDesugared(TypeLocBuilder &TLB, DeducedTypeLoc TL) {
4589 assert(isa<TemplateTypeParmType>(Replacement) &&(static_cast<void> (0))
4590 "unexpected unsugared replacement kind")(static_cast<void> (0));
4591 QualType Result = Replacement;
4592 TemplateTypeParmTypeLoc NewTL = TLB.push<TemplateTypeParmTypeLoc>(Result);
4593 NewTL.setNameLoc(TL.getNameLoc());
4594 return Result;
4595 }
4596
4597 QualType TransformAutoType(TypeLocBuilder &TLB, AutoTypeLoc TL) {
4598 // If we're building the type pattern to deduce against, don't wrap the
4599 // substituted type in an AutoType. Certain template deduction rules
4600 // apply only when a template type parameter appears directly (and not if
4601 // the parameter is found through desugaring). For instance:
4602 // auto &&lref = lvalue;
4603 // must transform into "rvalue reference to T" not "rvalue reference to
4604 // auto type deduced as T" in order for [temp.deduct.call]p3 to apply.
4605 //
4606 // FIXME: Is this still necessary?
4607 if (!UseTypeSugar)
4608 return TransformDesugared(TLB, TL);
4609
4610 QualType Result = SemaRef.Context.getAutoType(
4611 Replacement, TL.getTypePtr()->getKeyword(), Replacement.isNull(),
4612 ReplacementIsPack, TL.getTypePtr()->getTypeConstraintConcept(),
4613 TL.getTypePtr()->getTypeConstraintArguments());
4614 auto NewTL = TLB.push<AutoTypeLoc>(Result);
4615 NewTL.copy(TL);
4616 return Result;
4617 }
4618
4619 QualType TransformDeducedTemplateSpecializationType(
4620 TypeLocBuilder &TLB, DeducedTemplateSpecializationTypeLoc TL) {
4621 if (!UseTypeSugar)
4622 return TransformDesugared(TLB, TL);
4623
4624 QualType Result = SemaRef.Context.getDeducedTemplateSpecializationType(
4625 TL.getTypePtr()->getTemplateName(),
4626 Replacement, Replacement.isNull());
4627 auto NewTL = TLB.push<DeducedTemplateSpecializationTypeLoc>(Result);
4628 NewTL.setNameLoc(TL.getNameLoc());
4629 return Result;
4630 }
4631
4632 ExprResult TransformLambdaExpr(LambdaExpr *E) {
4633 // Lambdas never need to be transformed.
4634 return E;
4635 }
4636
4637 QualType Apply(TypeLoc TL) {
4638 // Create some scratch storage for the transformed type locations.
4639 // FIXME: We're just going to throw this information away. Don't build it.
4640 TypeLocBuilder TLB;
4641 TLB.reserve(TL.getFullDataSize());
4642 return TransformType(TLB, TL);
4643 }
4644 };
4645
4646} // namespace
4647
4648Sema::DeduceAutoResult
4649Sema::DeduceAutoType(TypeSourceInfo *Type, Expr *&Init, QualType &Result,
4650 Optional<unsigned> DependentDeductionDepth,
4651 bool IgnoreConstraints) {
4652 return DeduceAutoType(Type->getTypeLoc(), Init, Result,
4653 DependentDeductionDepth, IgnoreConstraints);
4654}
4655
4656/// Attempt to produce an informative diagostic explaining why auto deduction
4657/// failed.
4658/// \return \c true if diagnosed, \c false if not.
4659static bool diagnoseAutoDeductionFailure(Sema &S,
4660 Sema::TemplateDeductionResult TDK,
4661 TemplateDeductionInfo &Info,
4662 ArrayRef<SourceRange> Ranges) {
4663 switch (TDK) {
4664 case Sema::TDK_Inconsistent: {
4665 // Inconsistent deduction means we were deducing from an initializer list.
4666 auto D = S.Diag(Info.getLocation(), diag::err_auto_inconsistent_deduction);
4667 D << Info.FirstArg << Info.SecondArg;
4668 for (auto R : Ranges)
4669 D << R;
4670 return true;
4671 }
4672
4673 // FIXME: Are there other cases for which a custom diagnostic is more useful
4674 // than the basic "types don't match" diagnostic?
4675
4676 default:
4677 return false;
4678 }
4679}
4680
4681static Sema::DeduceAutoResult
4682CheckDeducedPlaceholderConstraints(Sema &S, const AutoType &Type,
4683 AutoTypeLoc TypeLoc, QualType Deduced) {
4684 ConstraintSatisfaction Satisfaction;
4685 ConceptDecl *Concept = Type.getTypeConstraintConcept();
4686 TemplateArgumentListInfo TemplateArgs(TypeLoc.getLAngleLoc(),
4687 TypeLoc.getRAngleLoc());
4688 TemplateArgs.addArgument(
4689 TemplateArgumentLoc(TemplateArgument(Deduced),
4690 S.Context.getTrivialTypeSourceInfo(
4691 Deduced, TypeLoc.getNameLoc())));
4692 for (unsigned I = 0, C = TypeLoc.getNumArgs(); I != C; ++I)
4693 TemplateArgs.addArgument(TypeLoc.getArgLoc(I));
4694
4695 llvm::SmallVector<TemplateArgument, 4> Converted;
4696 if (S.CheckTemplateArgumentList(Concept, SourceLocation(), TemplateArgs,
4697 /*PartialTemplateArgs=*/false, Converted))
4698 return Sema::DAR_FailedAlreadyDiagnosed;
4699 if (S.CheckConstraintSatisfaction(Concept, {Concept->getConstraintExpr()},
4700 Converted, TypeLoc.getLocalSourceRange(),
4701 Satisfaction))
4702 return Sema::DAR_FailedAlreadyDiagnosed;
4703 if (!Satisfaction.IsSatisfied) {
4704 std::string Buf;
4705 llvm::raw_string_ostream OS(Buf);
4706 OS << "'" << Concept->getName();
4707 if (TypeLoc.hasExplicitTemplateArgs()) {
4708 printTemplateArgumentList(
4709 OS, Type.getTypeConstraintArguments(), S.getPrintingPolicy(),
4710 Type.getTypeConstraintConcept()->getTemplateParameters());
4711 }
4712 OS << "'";
4713 OS.flush();
4714 S.Diag(TypeLoc.getConceptNameLoc(),
4715 diag::err_placeholder_constraints_not_satisfied)
4716 << Deduced << Buf << TypeLoc.getLocalSourceRange();
4717 S.DiagnoseUnsatisfiedConstraint(Satisfaction);
4718 return Sema::DAR_FailedAlreadyDiagnosed;
4719 }
4720 return Sema::DAR_Succeeded;
4721}
4722
4723/// Deduce the type for an auto type-specifier (C++11 [dcl.spec.auto]p6)
4724///
4725/// Note that this is done even if the initializer is dependent. (This is
4726/// necessary to support partial ordering of templates using 'auto'.)
4727/// A dependent type will be produced when deducing from a dependent type.
4728///
4729/// \param Type the type pattern using the auto type-specifier.
4730/// \param Init the initializer for the variable whose type is to be deduced.
4731/// \param Result if type deduction was successful, this will be set to the
4732/// deduced type.
4733/// \param DependentDeductionDepth Set if we should permit deduction in
4734/// dependent cases. This is necessary for template partial ordering with
4735/// 'auto' template parameters. The value specified is the template
4736/// parameter depth at which we should perform 'auto' deduction.
4737/// \param IgnoreConstraints Set if we should not fail if the deduced type does
4738/// not satisfy the type-constraint in the auto type.
4739Sema::DeduceAutoResult
4740Sema::DeduceAutoType(TypeLoc Type, Expr *&Init, QualType &Result,
4741 Optional<unsigned> DependentDeductionDepth,
4742 bool IgnoreConstraints) {
4743 if (Init->containsErrors())
4744 return DAR_FailedAlreadyDiagnosed;
4745 if (Init->getType()->isNonOverloadPlaceholderType()) {
4746 ExprResult NonPlaceholder = CheckPlaceholderExpr(Init);
4747 if (NonPlaceholder.isInvalid())
4748 return DAR_FailedAlreadyDiagnosed;
4749 Init = NonPlaceholder.get();
4750 }
4751
4752 DependentAuto DependentResult = {
4753 /*.IsPack = */ (bool)Type.getAs<PackExpansionTypeLoc>()};
4754
4755 if (!DependentDeductionDepth &&
4756 (Type.getType()->isDependentType() || Init->isTypeDependent() ||
4757 Init->containsUnexpandedParameterPack())) {
4758 Result = SubstituteDeducedTypeTransform(*this, DependentResult).Apply(Type);
4759 assert(!Result.isNull() && "substituting DependentTy can't fail")(static_cast<void> (0));
4760 return DAR_Succeeded;
4761 }
4762
4763 // Find the depth of template parameter to synthesize.
4764 unsigned Depth = DependentDeductionDepth.getValueOr(0);
4765
4766 // If this is a 'decltype(auto)' specifier, do the decltype dance.
4767 // Since 'decltype(auto)' can only occur at the top of the type, we
4768 // don't need to go digging for it.
4769 if (const AutoType *AT = Type.getType()->getAs<AutoType>()) {
4770 if (AT->isDecltypeAuto()) {
4771 if (isa<InitListExpr>(Init)) {
4772 Diag(Init->getBeginLoc(), diag::err_decltype_auto_initializer_list);
4773 return DAR_FailedAlreadyDiagnosed;
4774 }
4775
4776 ExprResult ER = CheckPlaceholderExpr(Init);
4777 if (ER.isInvalid())
4778 return DAR_FailedAlreadyDiagnosed;
4779 Init = ER.get();
4780 QualType Deduced = BuildDecltypeType(Init, Init->getBeginLoc(), false);
4781 if (Deduced.isNull())
4782 return DAR_FailedAlreadyDiagnosed;
4783 // FIXME: Support a non-canonical deduced type for 'auto'.
4784 Deduced = Context.getCanonicalType(Deduced);
4785 if (AT->isConstrained() && !IgnoreConstraints) {
4786 auto ConstraintsResult =
4787 CheckDeducedPlaceholderConstraints(*this, *AT,
4788 Type.getContainedAutoTypeLoc(),
4789 Deduced);
4790 if (ConstraintsResult != DAR_Succeeded)
4791 return ConstraintsResult;
4792 }
4793 Result = SubstituteDeducedTypeTransform(*this, Deduced).Apply(Type);
4794 if (Result.isNull())
4795 return DAR_FailedAlreadyDiagnosed;
4796 return DAR_Succeeded;
4797 } else if (!getLangOpts().CPlusPlus) {
4798 if (isa<InitListExpr>(Init)) {
4799 Diag(Init->getBeginLoc(), diag::err_auto_init_list_from_c);
4800 return DAR_FailedAlreadyDiagnosed;
4801 }
4802 }
4803 }
4804
4805 SourceLocation Loc = Init->getExprLoc();
4806
4807 LocalInstantiationScope InstScope(*this);
4808
4809 // Build template<class TemplParam> void Func(FuncParam);
4810 TemplateTypeParmDecl *TemplParam = TemplateTypeParmDecl::Create(
4811 Context, nullptr, SourceLocation(), Loc, Depth, 0, nullptr, false, false,
4812 false);
4813 QualType TemplArg = QualType(TemplParam->getTypeForDecl(), 0);
4814 NamedDecl *TemplParamPtr = TemplParam;
4815 FixedSizeTemplateParameterListStorage<1, false> TemplateParamsSt(
4816 Context, Loc, Loc, TemplParamPtr, Loc, nullptr);
4817
4818 QualType FuncParam =
4819 SubstituteDeducedTypeTransform(*this, TemplArg, /*UseTypeSugar*/false)
4820 .Apply(Type);
4821 assert(!FuncParam.isNull() &&(static_cast<void> (0))
4822 "substituting template parameter for 'auto' failed")(static_cast<void> (0));
4823
4824 // Deduce type of TemplParam in Func(Init)
4825 SmallVector<DeducedTemplateArgument, 1> Deduced;
4826 Deduced.resize(1);
4827
4828 TemplateDeductionInfo Info(Loc, Depth);
4829
4830 // If deduction failed, don't diagnose if the initializer is dependent; it
4831 // might acquire a matching type in the instantiation.
4832 auto DeductionFailed = [&](TemplateDeductionResult TDK,
4833 ArrayRef<SourceRange> Ranges) -> DeduceAutoResult {
4834 if (Init->isTypeDependent()) {
4835 Result =
4836 SubstituteDeducedTypeTransform(*this, DependentResult).Apply(Type);
4837 assert(!Result.isNull() && "substituting DependentTy can't fail")(static_cast<void> (0));
4838 return DAR_Succeeded;
4839 }
4840 if (diagnoseAutoDeductionFailure(*this, TDK, Info, Ranges))
4841 return DAR_FailedAlreadyDiagnosed;
4842 return DAR_Failed;
4843 };
4844
4845 SmallVector<OriginalCallArg, 4> OriginalCallArgs;
4846
4847 InitListExpr *InitList = dyn_cast<InitListExpr>(Init);
4848 if (InitList) {
4849 // Notionally, we substitute std::initializer_list<T> for 'auto' and deduce
4850 // against that. Such deduction only succeeds if removing cv-qualifiers and
4851 // references results in std::initializer_list<T>.
4852 if (!Type.getType().getNonReferenceType()->getAs<AutoType>())
4853 return DAR_Failed;
4854
4855 // Resolving a core issue: a braced-init-list containing any designators is
4856 // a non-deduced context.
4857 for (Expr *E : InitList->inits())
4858 if (isa<DesignatedInitExpr>(E))
4859 return DAR_Failed;
4860
4861 SourceRange DeducedFromInitRange;
4862 for (unsigned i = 0, e = InitList->getNumInits(); i < e; ++i) {
4863 Expr *Init = InitList->getInit(i);
4864
4865 if (auto TDK = DeduceTemplateArgumentsFromCallArgument(
4866 *this, TemplateParamsSt.get(), 0, TemplArg, Init,
4867 Info, Deduced, OriginalCallArgs, /*Decomposed*/ true,
4868 /*ArgIdx*/ 0, /*TDF*/ 0))
4869 return DeductionFailed(TDK, {DeducedFromInitRange,
4870 Init->getSourceRange()});
4871
4872 if (DeducedFromInitRange.isInvalid() &&
4873 Deduced[0].getKind() != TemplateArgument::Null)
4874 DeducedFromInitRange = Init->getSourceRange();
4875 }
4876 } else {
4877 if (!getLangOpts().CPlusPlus && Init->refersToBitField()) {
4878 Diag(Loc, diag::err_auto_bitfield);
4879 return DAR_FailedAlreadyDiagnosed;
4880 }
4881
4882 if (auto TDK = DeduceTemplateArgumentsFromCallArgument(
4883 *this, TemplateParamsSt.get(), 0, FuncParam, Init, Info, Deduced,
4884 OriginalCallArgs, /*Decomposed*/ false, /*ArgIdx*/ 0, /*TDF*/ 0))
4885 return DeductionFailed(TDK, {});
4886 }
4887
4888 // Could be null if somehow 'auto' appears in a non-deduced context.
4889 if (Deduced[0].getKind() != TemplateArgument::Type)
4890 return DeductionFailed(TDK_Incomplete, {});
4891
4892 QualType DeducedType = Deduced[0].getAsType();
4893
4894 if (InitList) {
4895 DeducedType = BuildStdInitializerList(DeducedType, Loc);
4896 if (DeducedType.isNull())
4897 return DAR_FailedAlreadyDiagnosed;
4898 }
4899
4900 if (const auto *AT = Type.getType()->getAs<AutoType>()) {
4901 if (AT->isConstrained() && !IgnoreConstraints) {
4902 auto ConstraintsResult =
4903 CheckDeducedPlaceholderConstraints(*this, *AT,
4904 Type.getContainedAutoTypeLoc(),
4905 DeducedType);
4906 if (ConstraintsResult != DAR_Succeeded)
4907 return ConstraintsResult;
4908 }
4909 }
4910
4911 Result = SubstituteDeducedTypeTransform(*this, DeducedType).Apply(Type);
4912 if (Result.isNull())
4913 return DAR_FailedAlreadyDiagnosed;
4914
4915 // Check that the deduced argument type is compatible with the original
4916 // argument type per C++ [temp.deduct.call]p4.
4917 QualType DeducedA = InitList ? Deduced[0].getAsType() : Result;
4918 for (const OriginalCallArg &OriginalArg : OriginalCallArgs) {
4919 assert((bool)InitList == OriginalArg.DecomposedParam &&(static_cast<void> (0))
4920 "decomposed non-init-list in auto deduction?")(static_cast<void> (0));
4921 if (auto TDK =
4922 CheckOriginalCallArgDeduction(*this, Info, OriginalArg, DeducedA)) {
4923 Result = QualType();
4924 return DeductionFailed(TDK, {});
4925 }
4926 }
4927
4928 return DAR_Succeeded;
4929}
4930
4931QualType Sema::SubstAutoType(QualType TypeWithAuto,
4932 QualType TypeToReplaceAuto) {
4933 if (TypeToReplaceAuto->isDependentType())
4934 return SubstituteDeducedTypeTransform(
4935 *this, DependentAuto{
4936 TypeToReplaceAuto->containsUnexpandedParameterPack()})
4937 .TransformType(TypeWithAuto);
4938 return SubstituteDeducedTypeTransform(*this, TypeToReplaceAuto)
4939 .TransformType(TypeWithAuto);
4940}
4941
4942TypeSourceInfo *Sema::SubstAutoTypeSourceInfo(TypeSourceInfo *TypeWithAuto,
4943 QualType TypeToReplaceAuto) {
4944 if (TypeToReplaceAuto->isDependentType())
4945 return SubstituteDeducedTypeTransform(
4946 *this,
4947 DependentAuto{
4948 TypeToReplaceAuto->containsUnexpandedParameterPack()})
4949 .TransformType(TypeWithAuto);
4950 return SubstituteDeducedTypeTransform(*this, TypeToReplaceAuto)
4951 .TransformType(TypeWithAuto);
4952}
4953
4954QualType Sema::ReplaceAutoType(QualType TypeWithAuto,
4955 QualType TypeToReplaceAuto) {
4956 return SubstituteDeducedTypeTransform(*this, TypeToReplaceAuto,
4957 /*UseTypeSugar*/ false)
4958 .TransformType(TypeWithAuto);
4959}
4960
4961TypeSourceInfo *Sema::ReplaceAutoTypeSourceInfo(TypeSourceInfo *TypeWithAuto,
4962 QualType TypeToReplaceAuto) {
4963 return SubstituteDeducedTypeTransform(*this, TypeToReplaceAuto,
4964 /*UseTypeSugar*/ false)
4965 .TransformType(TypeWithAuto);
4966}
4967
4968void Sema::DiagnoseAutoDeductionFailure(VarDecl *VDecl, Expr *Init) {
4969 if (isa<InitListExpr>(Init))
4970 Diag(VDecl->getLocation(),
4971 VDecl->isInitCapture()
4972 ? diag::err_init_capture_deduction_failure_from_init_list
4973 : diag::err_auto_var_deduction_failure_from_init_list)
4974 << VDecl->getDeclName() << VDecl->getType() << Init->getSourceRange();
4975 else
4976 Diag(VDecl->getLocation(),
4977 VDecl->isInitCapture() ? diag::err_init_capture_deduction_failure
4978 : diag::err_auto_var_deduction_failure)
4979 << VDecl->getDeclName() << VDecl->getType() << Init->getType()
4980 << Init->getSourceRange();
4981}
4982
4983bool Sema::DeduceReturnType(FunctionDecl *FD, SourceLocation Loc,
4984 bool Diagnose) {
4985 assert(FD->getReturnType()->isUndeducedType())(static_cast<void> (0));
4986
4987 // For a lambda's conversion operator, deduce any 'auto' or 'decltype(auto)'
4988 // within the return type from the call operator's type.
4989 if (isLambdaConversionOperator(FD)) {
4990 CXXRecordDecl *Lambda = cast<CXXMethodDecl>(FD)->getParent();
4991 FunctionDecl *CallOp = Lambda->getLambdaCallOperator();
4992
4993 // For a generic lambda, instantiate the call operator if needed.
4994 if (auto *Args = FD->getTemplateSpecializationArgs()) {
4995 CallOp = InstantiateFunctionDeclaration(
4996 CallOp->getDescribedFunctionTemplate(), Args, Loc);
4997 if (!CallOp || CallOp->isInvalidDecl())
4998 return true;
4999
5000 // We might need to deduce the return type by instantiating the definition
5001 // of the operator() function.
5002 if (CallOp->getReturnType()->isUndeducedType()) {
5003 runWithSufficientStackSpace(Loc, [&] {
5004 InstantiateFunctionDefinition(Loc, CallOp);
5005 });
5006 }
5007 }
5008
5009 if (CallOp->isInvalidDecl())
5010 return true;
5011 assert(!CallOp->getReturnType()->isUndeducedType() &&(static_cast<void> (0))
5012 "failed to deduce lambda return type")(static_cast<void> (0));
5013
5014 // Build the new return type from scratch.
5015 CallingConv RetTyCC = FD->getReturnType()
5016 ->getPointeeType()
5017 ->castAs<FunctionType>()
5018 ->getCallConv();
5019 QualType RetType = getLambdaConversionFunctionResultType(
5020 CallOp->getType()->castAs<FunctionProtoType>(), RetTyCC);
5021 if (FD->getReturnType()->getAs<PointerType>())
5022 RetType = Context.getPointerType(RetType);
5023 else {
5024 assert(FD->getReturnType()->getAs<BlockPointerType>())(static_cast<void> (0));
5025 RetType = Context.getBlockPointerType(RetType);
5026 }
5027 Context.adjustDeducedFunctionResultType(FD, RetType);
5028 return false;
5029 }
5030
5031 if (FD->getTemplateInstantiationPattern()) {
5032 runWithSufficientStackSpace(Loc, [&] {
5033 InstantiateFunctionDefinition(Loc, FD);
5034 });
5035 }
5036
5037 bool StillUndeduced = FD->getReturnType()->isUndeducedType();
5038 if (StillUndeduced && Diagnose && !FD->isInvalidDecl()) {
5039 Diag(Loc, diag::err_auto_fn_used_before_defined) << FD;
5040 Diag(FD->getLocation(), diag::note_callee_decl) << FD;
5041 }
5042
5043 return StillUndeduced;
5044}
5045
5046/// If this is a non-static member function,
5047static void
5048AddImplicitObjectParameterType(ASTContext &Context,
5049 CXXMethodDecl *Method,
5050 SmallVectorImpl<QualType> &ArgTypes) {
5051 // C++11 [temp.func.order]p3:
5052 // [...] The new parameter is of type "reference to cv A," where cv are
5053 // the cv-qualifiers of the function template (if any) and A is
5054 // the class of which the function template is a member.
5055 //
5056 // The standard doesn't say explicitly, but we pick the appropriate kind of
5057 // reference type based on [over.match.funcs]p4.
5058 QualType ArgTy = Context.getTypeDeclType(Method->getParent());
5059 ArgTy = Context.getQualifiedType(ArgTy, Method->getMethodQualifiers());
5060 if (Method->getRefQualifier() == RQ_RValue)
5061 ArgTy = Context.getRValueReferenceType(ArgTy);
5062 else
5063 ArgTy = Context.getLValueReferenceType(ArgTy);
5064 ArgTypes.push_back(ArgTy);
5065}
5066
5067/// Determine whether the function template \p FT1 is at least as
5068/// specialized as \p FT2.
5069static bool isAtLeastAsSpecializedAs(Sema &S,
5070 SourceLocation Loc,
5071 FunctionTemplateDecl *FT1,
5072 FunctionTemplateDecl *FT2,
5073 TemplatePartialOrderingContext TPOC,
5074 unsigned NumCallArguments1,
5075 bool Reversed) {
5076 assert(!Reversed || TPOC == TPOC_Call)(static_cast<void> (0));
5077
5078 FunctionDecl *FD1 = FT1->getTemplatedDecl();
5079 FunctionDecl *FD2 = FT2->getTemplatedDecl();
5080 const FunctionProtoType *Proto1 = FD1->getType()->getAs<FunctionProtoType>();
5081 const FunctionProtoType *Proto2 = FD2->getType()->getAs<FunctionProtoType>();
5082
5083 assert(Proto1 && Proto2 && "Function templates must have prototypes")(static_cast<void> (0));
5084 TemplateParameterList *TemplateParams = FT2->getTemplateParameters();
5085 SmallVector<DeducedTemplateArgument, 4> Deduced;
5086 Deduced.resize(TemplateParams->size());
5087
5088 // C++0x [temp.deduct.partial]p3:
5089 // The types used to determine the ordering depend on the context in which
5090 // the partial ordering is done:
5091 TemplateDeductionInfo Info(Loc);
5092 SmallVector<QualType, 4> Args2;
5093 switch (TPOC) {
5094 case TPOC_Call: {
5095 // - In the context of a function call, the function parameter types are
5096 // used.
5097 CXXMethodDecl *Method1 = dyn_cast<CXXMethodDecl>(FD1);
5098 CXXMethodDecl *Method2 = dyn_cast<CXXMethodDecl>(FD2);
5099
5100 // C++11 [temp.func.order]p3:
5101 // [...] If only one of the function templates is a non-static
5102 // member, that function template is considered to have a new
5103 // first parameter inserted in its function parameter list. The
5104 // new parameter is of type "reference to cv A," where cv are
5105 // the cv-qualifiers of the function template (if any) and A is
5106 // the class of which the function template is a member.
5107 //
5108 // Note that we interpret this to mean "if one of the function
5109 // templates is a non-static member and the other is a non-member";
5110 // otherwise, the ordering rules for static functions against non-static
5111 // functions don't make any sense.
5112 //
5113 // C++98/03 doesn't have this provision but we've extended DR532 to cover
5114 // it as wording was broken prior to it.
5115 SmallVector<QualType, 4> Args1;
5116
5117 unsigned NumComparedArguments = NumCallArguments1;
5118
5119 if (!Method2 && Method1 && !Method1->isStatic()) {
5120 // Compare 'this' from Method1 against first parameter from Method2.
5121 AddImplicitObjectParameterType(S.Context, Method1, Args1);
5122 ++NumComparedArguments;
5123 } else if (!Method1 && Method2 && !Method2->isStatic()) {
5124 // Compare 'this' from Method2 against first parameter from Method1.
5125 AddImplicitObjectParameterType(S.Context, Method2, Args2);
5126 } else if (Method1 && Method2 && Reversed) {
5127 // Compare 'this' from Method1 against second parameter from Method2
5128 // and 'this' from Method2 against second parameter from Method1.
5129 AddImplicitObjectParameterType(S.Context, Method1, Args1);
5130 AddImplicitObjectParameterType(S.Context, Method2, Args2);
5131 ++NumComparedArguments;
5132 }
5133
5134 Args1.insert(Args1.end(), Proto1->param_type_begin(),
5135 Proto1->param_type_end());
5136 Args2.insert(Args2.end(), Proto2->param_type_begin(),
5137 Proto2->param_type_end());
5138
5139 // C++ [temp.func.order]p5:
5140 // The presence of unused ellipsis and default arguments has no effect on
5141 // the partial ordering of function templates.
5142 if (Args1.size() > NumComparedArguments)
5143 Args1.resize(NumComparedArguments);
5144 if (Args2.size() > NumComparedArguments)
5145 Args2.resize(NumComparedArguments);
5146 if (Reversed)
5147 std::reverse(Args2.begin(), Args2.end());
5148 if (DeduceTemplateArguments(S, TemplateParams, Args2.data(), Args2.size(),
5149 Args1.data(), Args1.size(), Info, Deduced,
5150 TDF_None, /*PartialOrdering=*/true))
5151 return false;
5152
5153 break;
5154 }
5155
5156 case TPOC_Conversion:
5157 // - In the context of a call to a conversion operator, the return types
5158 // of the conversion function templates are used.
5159 if (DeduceTemplateArgumentsByTypeMatch(
5160 S, TemplateParams, Proto2->getReturnType(), Proto1->getReturnType(),
5161 Info, Deduced, TDF_None,
5162 /*PartialOrdering=*/true))
5163 return false;
5164 break;
5165
5166 case TPOC_Other:
5167 // - In other contexts (14.6.6.2) the function template's function type
5168 // is used.
5169 if (DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
5170 FD2->getType(), FD1->getType(),
5171 Info, Deduced, TDF_None,
5172 /*PartialOrdering=*/true))
5173 return false;
5174 break;
5175 }
5176
5177 // C++0x [temp.deduct.partial]p11:
5178 // In most cases, all template parameters must have values in order for
5179 // deduction to succeed, but for partial ordering purposes a template
5180 // parameter may remain without a value provided it is not used in the
5181 // types being used for partial ordering. [ Note: a template parameter used
5182 // in a non-deduced context is considered used. -end note]
5183 unsigned ArgIdx = 0, NumArgs = Deduced.size();
5184 for (; ArgIdx != NumArgs; ++ArgIdx)
5185 if (Deduced[ArgIdx].isNull())
5186 break;
5187
5188 // FIXME: We fail to implement [temp.deduct.type]p1 along this path. We need
5189 // to substitute the deduced arguments back into the template and check that
5190 // we get the right type.
5191
5192 if (ArgIdx == NumArgs) {
5193 // All template arguments were deduced. FT1 is at least as specialized
5194 // as FT2.
5195 return true;
5196 }
5197
5198 // Figure out which template parameters were used.
5199 llvm::SmallBitVector UsedParameters(TemplateParams->size());
5200 switch (TPOC) {
5201 case TPOC_Call:
5202 for (unsigned I = 0, N = Args2.size(); I != N; ++I)
5203 ::MarkUsedTemplateParameters(S.Context, Args2[I], false,
5204 TemplateParams->getDepth(),
5205 UsedParameters);
5206 break;
5207
5208 case TPOC_Conversion:
5209 ::MarkUsedTemplateParameters(S.Context, Proto2->getReturnType(), false,
5210 TemplateParams->getDepth(), UsedParameters);
5211 break;
5212
5213 case TPOC_Other:
5214 ::MarkUsedTemplateParameters(S.Context, FD2->getType(), false,
5215 TemplateParams->getDepth(),
5216 UsedParameters);
5217 break;
5218 }
5219
5220 for (; ArgIdx != NumArgs; ++ArgIdx)
5221 // If this argument had no value deduced but was used in one of the types
5222 // used for partial ordering, then deduction fails.
5223 if (Deduced[ArgIdx].isNull() && UsedParameters[ArgIdx])
5224 return false;
5225
5226 return true;
5227}
5228
5229/// Determine whether this a function template whose parameter-type-list
5230/// ends with a function parameter pack.
5231static bool isVariadicFunctionTemplate(FunctionTemplateDecl *FunTmpl) {
5232 FunctionDecl *Function = FunTmpl->getTemplatedDecl();
5233 unsigned NumParams = Function->getNumParams();
5234 if (NumParams == 0)
5235 return false;
5236
5237 ParmVarDecl *Last = Function->getParamDecl(NumParams - 1);
5238 if (!Last->isParameterPack())
5239 return false;
5240
5241 // Make sure that no previous parameter is a parameter pack.
5242 while (--NumParams > 0) {
5243 if (Function->getParamDecl(NumParams - 1)->isParameterPack())
5244 return false;
5245 }
5246
5247 return true;
5248}
5249
5250/// Returns the more specialized function template according
5251/// to the rules of function template partial ordering (C++ [temp.func.order]).
5252///
5253/// \param FT1 the first function template
5254///
5255/// \param FT2 the second function template
5256///
5257/// \param TPOC the context in which we are performing partial ordering of
5258/// function templates.
5259///
5260/// \param NumCallArguments1 The number of arguments in the call to FT1, used
5261/// only when \c TPOC is \c TPOC_Call.
5262///
5263/// \param NumCallArguments2 The number of arguments in the call to FT2, used
5264/// only when \c TPOC is \c TPOC_Call.
5265///
5266/// \param Reversed If \c true, exactly one of FT1 and FT2 is an overload
5267/// candidate with a reversed parameter order. In this case, the corresponding
5268/// P/A pairs between FT1 and FT2 are reversed.
5269///
5270/// \returns the more specialized function template. If neither
5271/// template is more specialized, returns NULL.
5272FunctionTemplateDecl *
5273Sema::getMoreSpecializedTemplate(FunctionTemplateDecl *FT1,
5274 FunctionTemplateDecl *FT2,
5275 SourceLocation Loc,
5276 TemplatePartialOrderingContext TPOC,
5277 unsigned NumCallArguments1,
5278 unsigned NumCallArguments2,
5279 bool Reversed) {
5280
5281 auto JudgeByConstraints = [&] () -> FunctionTemplateDecl * {
5282 llvm::SmallVector<const Expr *, 3> AC1, AC2;
5283 FT1->getAssociatedConstraints(AC1);
5284 FT2->getAssociatedConstraints(AC2);
5285 bool AtLeastAsConstrained1, AtLeastAsConstrained2;
5286 if (IsAtLeastAsConstrained(FT1, AC1, FT2, AC2, AtLeastAsConstrained1))
5287 return nullptr;
5288 if (IsAtLeastAsConstrained(FT2, AC2, FT1, AC1, AtLeastAsConstrained2))
5289 return nullptr;
5290 if (AtLeastAsConstrained1 == AtLeastAsConstrained2)
5291 return nullptr;
5292 return AtLeastAsConstrained1 ? FT1 : FT2;
5293 };
5294
5295 bool Better1 = isAtLeastAsSpecializedAs(*this, Loc, FT1, FT2, TPOC,
5296 NumCallArguments1, Reversed);
5297 bool Better2 = isAtLeastAsSpecializedAs(*this, Loc, FT2, FT1, TPOC,
5298 NumCallArguments2, Reversed);
5299
5300 if (Better1 != Better2) // We have a clear winner
5301 return Better1 ? FT1 : FT2;
5302
5303 if (!Better1 && !Better2) // Neither is better than the other
5304 return JudgeByConstraints();
5305
5306 // FIXME: This mimics what GCC implements, but doesn't match up with the
5307 // proposed resolution for core issue 692. This area needs to be sorted out,
5308 // but for now we attempt to maintain compatibility.
5309 bool Variadic1 = isVariadicFunctionTemplate(FT1);
5310 bool Variadic2 = isVariadicFunctionTemplate(FT2);
5311 if (Variadic1 != Variadic2)
5312 return Variadic1? FT2 : FT1;
5313
5314 return JudgeByConstraints();
5315}
5316
5317/// Determine if the two templates are equivalent.
5318static bool isSameTemplate(TemplateDecl *T1, TemplateDecl *T2) {
5319 if (T1 == T2)
5320 return true;
5321
5322 if (!T1 || !T2)
5323 return false;
5324
5325 return T1->getCanonicalDecl() == T2->getCanonicalDecl();
5326}
5327
5328/// Retrieve the most specialized of the given function template
5329/// specializations.
5330///
5331/// \param SpecBegin the start iterator of the function template
5332/// specializations that we will be comparing.
5333///
5334/// \param SpecEnd the end iterator of the function template
5335/// specializations, paired with \p SpecBegin.
5336///
5337/// \param Loc the location where the ambiguity or no-specializations
5338/// diagnostic should occur.
5339///
5340/// \param NoneDiag partial diagnostic used to diagnose cases where there are
5341/// no matching candidates.
5342///
5343/// \param AmbigDiag partial diagnostic used to diagnose an ambiguity, if one
5344/// occurs.
5345///
5346/// \param CandidateDiag partial diagnostic used for each function template
5347/// specialization that is a candidate in the ambiguous ordering. One parameter
5348/// in this diagnostic should be unbound, which will correspond to the string
5349/// describing the template arguments for the function template specialization.
5350///
5351/// \returns the most specialized function template specialization, if
5352/// found. Otherwise, returns SpecEnd.
5353UnresolvedSetIterator Sema::getMostSpecialized(
5354 UnresolvedSetIterator SpecBegin, UnresolvedSetIterator SpecEnd,
5355 TemplateSpecCandidateSet &FailedCandidates,
5356 SourceLocation Loc, const PartialDiagnostic &NoneDiag,
5357 const PartialDiagnostic &AmbigDiag, const PartialDiagnostic &CandidateDiag,
5358 bool Complain, QualType TargetType) {
5359 if (SpecBegin == SpecEnd) {
5360 if (Complain) {
5361 Diag(Loc, NoneDiag);
5362 FailedCandidates.NoteCandidates(*this, Loc);
5363 }
5364 return SpecEnd;
5365 }
5366
5367 if (SpecBegin + 1 == SpecEnd)
5368 return SpecBegin;
5369
5370 // Find the function template that is better than all of the templates it
5371 // has been compared to.
5372 UnresolvedSetIterator Best = SpecBegin;
5373 FunctionTemplateDecl *BestTemplate
5374 = cast<FunctionDecl>(*Best)->getPrimaryTemplate();
5375 assert(BestTemplate && "Not a function template specialization?")(static_cast<void> (0));
5376 for (UnresolvedSetIterator I = SpecBegin + 1; I != SpecEnd; ++I) {
5377 FunctionTemplateDecl *Challenger
5378 = cast<FunctionDecl>(*I)->getPrimaryTemplate();
5379 assert(Challenger && "Not a function template specialization?")(static_cast<void> (0));
5380 if (isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger,
5381 Loc, TPOC_Other, 0, 0),
5382 Challenger)) {
5383 Best = I;
5384 BestTemplate = Challenger;
5385 }
5386 }
5387
5388 // Make sure that the "best" function template is more specialized than all
5389 // of the others.
5390 bool Ambiguous = false;
5391 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) {
5392 FunctionTemplateDecl *Challenger
5393 = cast<FunctionDecl>(*I)->getPrimaryTemplate();
5394 if (I != Best &&
5395 !isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger,
5396 Loc, TPOC_Other, 0, 0),
5397 BestTemplate)) {
5398 Ambiguous = true;
5399 break;
5400 }
5401 }
5402
5403 if (!Ambiguous) {
5404 // We found an answer. Return it.
5405 return Best;
5406 }
5407
5408 // Diagnose the ambiguity.
5409 if (Complain) {
5410 Diag(Loc, AmbigDiag);
5411
5412 // FIXME: Can we order the candidates in some sane way?
5413 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) {
5414 PartialDiagnostic PD = CandidateDiag;
5415 const auto *FD = cast<FunctionDecl>(*I);
5416 PD << FD << getTemplateArgumentBindingsText(
5417 FD->getPrimaryTemplate()->getTemplateParameters(),
5418 *FD->getTemplateSpecializationArgs());
5419 if (!TargetType.isNull())
5420 HandleFunctionTypeMismatch(PD, FD->getType(), TargetType);
5421 Diag((*I)->getLocation(), PD);
5422 }
5423 }
5424
5425 return SpecEnd;
5426}
5427
5428/// Determine whether one partial specialization, P1, is at least as
5429/// specialized than another, P2.
5430///
5431/// \tparam TemplateLikeDecl The kind of P2, which must be a
5432/// TemplateDecl or {Class,Var}TemplatePartialSpecializationDecl.
5433/// \param T1 The injected-class-name of P1 (faked for a variable template).
5434/// \param T2 The injected-class-name of P2 (faked for a variable template).
5435template<typename TemplateLikeDecl>
5436static bool isAtLeastAsSpecializedAs(Sema &S, QualType T1, QualType T2,
5437 TemplateLikeDecl *P2,
5438 TemplateDeductionInfo &Info) {
5439 // C++ [temp.class.order]p1:
5440 // For two class template partial specializations, the first is at least as
5441 // specialized as the second if, given the following rewrite to two
5442 // function templates, the first function template is at least as
5443 // specialized as the second according to the ordering rules for function
5444 // templates (14.6.6.2):
5445 // - the first function template has the same template parameters as the
5446 // first partial specialization and has a single function parameter
5447 // whose type is a class template specialization with the template
5448 // arguments of the first partial specialization, and
5449 // - the second function template has the same template parameters as the
5450 // second partial specialization and has a single function parameter
5451 // whose type is a class template specialization with the template
5452 // arguments of the second partial specialization.
5453 //
5454 // Rather than synthesize function templates, we merely perform the
5455 // equivalent partial ordering by performing deduction directly on
5456 // the template arguments of the class template partial
5457 // specializations. This computation is slightly simpler than the
5458 // general problem of function template partial ordering, because
5459 // class template partial specializations are more constrained. We
5460 // know that every template parameter is deducible from the class
5461 // template partial specialization's template arguments, for
5462 // example.
5463 SmallVector<DeducedTemplateArgument, 4> Deduced;
5464
5465 // Determine whether P1 is at least as specialized as P2.
5466 Deduced.resize(P2->getTemplateParameters()->size());
5467 if (DeduceTemplateArgumentsByTypeMatch(S, P2->getTemplateParameters(),
5468 T2, T1, Info, Deduced, TDF_None,
5469 /*PartialOrdering=*/true))
5470 return false;
5471
5472 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(),
5473 Deduced.end());
5474 Sema::InstantiatingTemplate Inst(S, Info.getLocation(), P2, DeducedArgs,
5475 Info);
5476 if (Inst.isInvalid())
5477 return false;
5478
5479 auto *TST1 = T1->castAs<TemplateSpecializationType>();
5480 bool AtLeastAsSpecialized;
5481 S.runWithSufficientStackSpace(Info.getLocation(), [&] {
5482 AtLeastAsSpecialized = !FinishTemplateArgumentDeduction(
5483 S, P2, /*IsPartialOrdering=*/true,
5484 TemplateArgumentList(TemplateArgumentList::OnStack,
5485 TST1->template_arguments()),
5486 Deduced, Info);
5487 });
5488 return AtLeastAsSpecialized;
5489}
5490
5491/// Returns the more specialized class template partial specialization
5492/// according to the rules of partial ordering of class template partial
5493/// specializations (C++ [temp.class.order]).
5494///
5495/// \param PS1 the first class template partial specialization
5496///
5497/// \param PS2 the second class template partial specialization
5498///
5499/// \returns the more specialized class template partial specialization. If
5500/// neither partial specialization is more specialized, returns NULL.
5501ClassTemplatePartialSpecializationDecl *
5502Sema::getMoreSpecializedPartialSpecialization(
5503 ClassTemplatePartialSpecializationDecl *PS1,
5504 ClassTemplatePartialSpecializationDecl *PS2,
5505 SourceLocation Loc) {
5506 QualType PT1 = PS1->getInjectedSpecializationType();
5507 QualType PT2 = PS2->getInjectedSpecializationType();
5508
5509 TemplateDeductionInfo Info(Loc);
5510 bool Better1 = isAtLeastAsSpecializedAs(*this, PT1, PT2, PS2, Info);
5511 bool Better2 = isAtLeastAsSpecializedAs(*this, PT2, PT1, PS1, Info);
5512
5513 if (!Better1 && !Better2)
5514 return nullptr;
5515 if (Better1 && Better2) {
5516 llvm::SmallVector<const Expr *, 3> AC1, AC2;
5517 PS1->getAssociatedConstraints(AC1);
5518 PS2->getAssociatedConstraints(AC2);
5519 bool AtLeastAsConstrained1, AtLeastAsConstrained2;
5520 if (IsAtLeastAsConstrained(PS1, AC1, PS2, AC2, AtLeastAsConstrained1))
5521 return nullptr;
5522 if (IsAtLeastAsConstrained(PS2, AC2, PS1, AC1, AtLeastAsConstrained2))
5523 return nullptr;
5524 if (AtLeastAsConstrained1 == AtLeastAsConstrained2)
5525 return nullptr;
5526 return AtLeastAsConstrained1 ? PS1 : PS2;
5527 }
5528
5529 return Better1 ? PS1 : PS2;
5530}
5531
5532bool Sema::isMoreSpecializedThanPrimary(
5533 ClassTemplatePartialSpecializationDecl *Spec, TemplateDeductionInfo &Info) {
5534 ClassTemplateDecl *Primary = Spec->getSpecializedTemplate();
5535 QualType PrimaryT = Primary->getInjectedClassNameSpecialization();
5536 QualType PartialT = Spec->getInjectedSpecializationType();
5537 if (!isAtLeastAsSpecializedAs(*this, PartialT, PrimaryT, Primary, Info))
5538 return false;
5539 if (!isAtLeastAsSpecializedAs(*this, PrimaryT, PartialT, Spec, Info))
5540 return true;
5541 Info.clearSFINAEDiagnostic();
5542 llvm::SmallVector<const Expr *, 3> PrimaryAC, SpecAC;
5543 Primary->getAssociatedConstraints(PrimaryAC);
5544 Spec->getAssociatedConstraints(SpecAC);
5545 bool AtLeastAsConstrainedPrimary, AtLeastAsConstrainedSpec;
5546 if (IsAtLeastAsConstrained(Spec, SpecAC, Primary, PrimaryAC,
5547 AtLeastAsConstrainedSpec))
5548 return false;
5549 if (!AtLeastAsConstrainedSpec)
5550 return false;
5551 if (IsAtLeastAsConstrained(Primary, PrimaryAC, Spec, SpecAC,
5552 AtLeastAsConstrainedPrimary))
5553 return false;
5554 return !AtLeastAsConstrainedPrimary;
5555}
5556
5557VarTemplatePartialSpecializationDecl *
5558Sema::getMoreSpecializedPartialSpecialization(
5559 VarTemplatePartialSpecializationDecl *PS1,
5560 VarTemplatePartialSpecializationDecl *PS2, SourceLocation Loc) {
5561 // Pretend the variable template specializations are class template
5562 // specializations and form a fake injected class name type for comparison.
5563 assert(PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate() &&(static_cast<void> (0))
5564 "the partial specializations being compared should specialize"(static_cast<void> (0))
5565 " the same template.")(static_cast<void> (0));
5566 TemplateName Name(PS1->getSpecializedTemplate());
5567 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
5568 QualType PT1 = Context.getTemplateSpecializationType(
5569 CanonTemplate, PS1->getTemplateArgs().asArray());
5570 QualType PT2 = Context.getTemplateSpecializationType(
5571 CanonTemplate, PS2->getTemplateArgs().asArray());
5572
5573 TemplateDeductionInfo Info(Loc);
5574 bool Better1 = isAtLeastAsSpecializedAs(*this, PT1, PT2, PS2, Info);
5575 bool Better2 = isAtLeastAsSpecializedAs(*this, PT2, PT1, PS1, Info);
5576
5577 if (!Better1 && !Better2)
5578 return nullptr;
5579 if (Better1 && Better2) {
5580 llvm::SmallVector<const Expr *, 3> AC1, AC2;
5581 PS1->getAssociatedConstraints(AC1);
5582 PS2->getAssociatedConstraints(AC2);
5583 bool AtLeastAsConstrained1, AtLeastAsConstrained2;
5584 if (IsAtLeastAsConstrained(PS1, AC1, PS2, AC2, AtLeastAsConstrained1))
5585 return nullptr;
5586 if (IsAtLeastAsConstrained(PS2, AC2, PS1, AC1, AtLeastAsConstrained2))
5587 return nullptr;
5588 if (AtLeastAsConstrained1 == AtLeastAsConstrained2)
5589 return nullptr;
5590 return AtLeastAsConstrained1 ? PS1 : PS2;
5591 }
5592
5593 return Better1 ? PS1 : PS2;
5594}
5595
5596bool Sema::isMoreSpecializedThanPrimary(
5597 VarTemplatePartialSpecializationDecl *Spec, TemplateDeductionInfo &Info) {
5598 TemplateDecl *Primary = Spec->getSpecializedTemplate();
5599 // FIXME: Cache the injected template arguments rather than recomputing
5600 // them for each partial specialization.
5601 SmallVector<TemplateArgument, 8> PrimaryArgs;
5602 Context.getInjectedTemplateArgs(Primary->getTemplateParameters(),
5603 PrimaryArgs);
5604
5605 TemplateName CanonTemplate =
5606 Context.getCanonicalTemplateName(TemplateName(Primary));
5607 QualType PrimaryT = Context.getTemplateSpecializationType(
5608 CanonTemplate, PrimaryArgs);
5609 QualType PartialT = Context.getTemplateSpecializationType(
5610 CanonTemplate, Spec->getTemplateArgs().asArray());
5611
5612 if (!isAtLeastAsSpecializedAs(*this, PartialT, PrimaryT, Primary, Info))
5613 return false;
5614 if (!isAtLeastAsSpecializedAs(*this, PrimaryT, PartialT, Spec, Info))
5615 return true;
5616 Info.clearSFINAEDiagnostic();
5617 llvm::SmallVector<const Expr *, 3> PrimaryAC, SpecAC;
5618 Primary->getAssociatedConstraints(PrimaryAC);
5619 Spec->getAssociatedConstraints(SpecAC);
5620 bool AtLeastAsConstrainedPrimary, AtLeastAsConstrainedSpec;
5621 if (IsAtLeastAsConstrained(Spec, SpecAC, Primary, PrimaryAC,
5622 AtLeastAsConstrainedSpec))
5623 return false;
5624 if (!AtLeastAsConstrainedSpec)
5625 return false;
5626 if (IsAtLeastAsConstrained(Primary, PrimaryAC, Spec, SpecAC,
5627 AtLeastAsConstrainedPrimary))
5628 return false;
5629 return !AtLeastAsConstrainedPrimary;
5630}
5631
5632bool Sema::isTemplateTemplateParameterAtLeastAsSpecializedAs(
5633 TemplateParameterList *P, TemplateDecl *AArg, SourceLocation Loc) {
5634 // C++1z [temp.arg.template]p4: (DR 150)
5635 // A template template-parameter P is at least as specialized as a
5636 // template template-argument A if, given the following rewrite to two
5637 // function templates...
5638
5639 // Rather than synthesize function templates, we merely perform the
5640 // equivalent partial ordering by performing deduction directly on
5641 // the template parameter lists of the template template parameters.
5642 //
5643 // Given an invented class template X with the template parameter list of
5644 // A (including default arguments):
5645 TemplateName X = Context.getCanonicalTemplateName(TemplateName(AArg));
5646 TemplateParameterList *A = AArg->getTemplateParameters();
5647
5648 // - Each function template has a single function parameter whose type is
5649 // a specialization of X with template arguments corresponding to the
5650 // template parameters from the respective function template
5651 SmallVector<TemplateArgument, 8> AArgs;
5652 Context.getInjectedTemplateArgs(A, AArgs);
5653
5654 // Check P's arguments against A's parameter list. This will fill in default
5655 // template arguments as needed. AArgs are already correct by construction.
5656 // We can't just use CheckTemplateIdType because that will expand alias
5657 // templates.
5658 SmallVector<TemplateArgument, 4> PArgs;
5659 {
5660 SFINAETrap Trap(*this);
5661
5662 Context.getInjectedTemplateArgs(P, PArgs);
5663 TemplateArgumentListInfo PArgList(P->getLAngleLoc(),
5664 P->getRAngleLoc());
5665 for (unsigned I = 0, N = P->size(); I != N; ++I) {
5666 // Unwrap packs that getInjectedTemplateArgs wrapped around pack
5667 // expansions, to form an "as written" argument list.
5668 TemplateArgument Arg = PArgs[I];
5669 if (Arg.getKind() == TemplateArgument::Pack) {
5670 assert(Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion())(static_cast<void> (0));
5671 Arg = *Arg.pack_begin();
5672 }
5673 PArgList.addArgument(getTrivialTemplateArgumentLoc(
5674 Arg, QualType(), P->getParam(I)->getLocation()));
5675 }
5676 PArgs.clear();
5677
5678 // C++1z [temp.arg.template]p3:
5679 // If the rewrite produces an invalid type, then P is not at least as
5680 // specialized as A.
5681 if (CheckTemplateArgumentList(AArg, Loc, PArgList, false, PArgs) ||
5682 Trap.hasErrorOccurred())
5683 return false;
5684 }
5685
5686 QualType AType = Context.getTemplateSpecializationType(X, AArgs);
5687 QualType PType = Context.getTemplateSpecializationType(X, PArgs);
5688
5689 // ... the function template corresponding to P is at least as specialized
5690 // as the function template corresponding to A according to the partial
5691 // ordering rules for function templates.
5692 TemplateDeductionInfo Info(Loc, A->getDepth());
5693 return isAtLeastAsSpecializedAs(*this, PType, AType, AArg, Info);
5694}
5695
5696namespace {
5697struct MarkUsedTemplateParameterVisitor :
5698 RecursiveASTVisitor<MarkUsedTemplateParameterVisitor> {
5699 llvm::SmallBitVector &Used;
5700 unsigned Depth;
5701
5702 MarkUsedTemplateParameterVisitor(llvm::SmallBitVector &Used,
5703 unsigned Depth)
5704 : Used(Used), Depth(Depth) { }
5705
5706 bool VisitTemplateTypeParmType(TemplateTypeParmType *T) {
5707 if (T->getDepth() == Depth)
5708 Used[T->getIndex()] = true;
5709 return true;
5710 }
5711
5712 bool TraverseTemplateName(TemplateName Template) {
5713 if (auto *TTP =
5714 dyn_cast<TemplateTemplateParmDecl>(Template.getAsTemplateDecl()))
5715 if (TTP->getDepth() == Depth)
5716 Used[TTP->getIndex()] = true;
5717 RecursiveASTVisitor<MarkUsedTemplateParameterVisitor>::
5718 TraverseTemplateName(Template);
5719 return true;
5720 }
5721
5722 bool VisitDeclRefExpr(DeclRefExpr *E) {
5723 if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(E->getDecl()))
5724 if (NTTP->getDepth() == Depth)
5725 Used[NTTP->getIndex()] = true;
5726 return true;
5727 }
5728};
5729}
5730
5731/// Mark the template parameters that are used by the given
5732/// expression.
5733static void
5734MarkUsedTemplateParameters(ASTContext &Ctx,
5735 const Expr *E,
5736 bool OnlyDeduced,
5737 unsigned Depth,
5738 llvm::SmallBitVector &Used) {
5739 if (!OnlyDeduced) {
5740 MarkUsedTemplateParameterVisitor(Used, Depth)
5741 .TraverseStmt(const_cast<Expr *>(E));
5742 return;
5743 }
5744
5745 // We can deduce from a pack expansion.
5746 if (const PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(E))
5747 E = Expansion->getPattern();
5748
5749 const NonTypeTemplateParmDecl *NTTP = getDeducedParameterFromExpr(E, Depth);
5750 if (!NTTP)
5751 return;
5752
5753 if (NTTP->getDepth() == Depth)
5754 Used[NTTP->getIndex()] = true;
5755
5756 // In C++17 mode, additional arguments may be deduced from the type of a
5757 // non-type argument.
5758 if (Ctx.getLangOpts().CPlusPlus17)
5759 MarkUsedTemplateParameters(Ctx, NTTP->getType(), OnlyDeduced, Depth, Used);
5760}
5761
5762/// Mark the template parameters that are used by the given
5763/// nested name specifier.
5764static void
5765MarkUsedTemplateParameters(ASTContext &Ctx,
5766 NestedNameSpecifier *NNS,
5767 bool OnlyDeduced,
5768 unsigned Depth,
5769 llvm::SmallBitVector &Used) {
5770 if (!NNS)
5771 return;
5772
5773 MarkUsedTemplateParameters(Ctx, NNS->getPrefix(), OnlyDeduced, Depth,
5774 Used);
5775 MarkUsedTemplateParameters(Ctx, QualType(NNS->getAsType(), 0),
5776 OnlyDeduced, Depth, Used);
5777}
5778
5779/// Mark the template parameters that are used by the given
5780/// template name.
5781static void
5782MarkUsedTemplateParameters(ASTContext &Ctx,
5783 TemplateName Name,
5784 bool OnlyDeduced,
5785 unsigned Depth,
5786 llvm::SmallBitVector &Used) {
5787 if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
5788 if (TemplateTemplateParmDecl *TTP
5789 = dyn_cast<TemplateTemplateParmDecl>(Template)) {
5790 if (TTP->getDepth() == Depth)
5791 Used[TTP->getIndex()] = true;
5792 }
5793 return;
5794 }
5795
5796 if (QualifiedTemplateName *QTN = Name.getAsQualifiedTemplateName())
5797 MarkUsedTemplateParameters(Ctx, QTN->getQualifier(), OnlyDeduced,
5798 Depth, Used);
5799 if (DependentTemplateName *DTN = Name.getAsDependentTemplateName())
5800 MarkUsedTemplateParameters(Ctx, DTN->getQualifier(), OnlyDeduced,
5801 Depth, Used);
5802}
5803
5804/// Mark the template parameters that are used by the given
5805/// type.
5806static void
5807MarkUsedTemplateParameters(ASTContext &Ctx, QualType T,
5808 bool OnlyDeduced,
5809 unsigned Depth,
5810 llvm::SmallBitVector &Used) {
5811 if (T.isNull())
5812 return;
5813
5814 // Non-dependent types have nothing deducible
5815 if (!T->isDependentType())
5816 return;
5817
5818 T = Ctx.getCanonicalType(T);
5819 switch (T->getTypeClass()) {
5820 case Type::Pointer:
5821 MarkUsedTemplateParameters(Ctx,
5822 cast<PointerType>(T)->getPointeeType(),
5823 OnlyDeduced,
5824 Depth,
5825 Used);
5826 break;
5827
5828 case Type::BlockPointer:
5829 MarkUsedTemplateParameters(Ctx,
5830 cast<BlockPointerType>(T)->getPointeeType(),
5831 OnlyDeduced,
5832 Depth,
5833 Used);
5834 break;
5835
5836 case Type::LValueReference:
5837 case Type::RValueReference:
5838 MarkUsedTemplateParameters(Ctx,
5839 cast<ReferenceType>(T)->getPointeeType(),
5840 OnlyDeduced,
5841 Depth,
5842 Used);
5843 break;
5844
5845 case Type::MemberPointer: {
5846 const MemberPointerType *MemPtr = cast<MemberPointerType>(T.getTypePtr());
5847 MarkUsedTemplateParameters(Ctx, MemPtr->getPointeeType(), OnlyDeduced,
5848 Depth, Used);
5849 MarkUsedTemplateParameters(Ctx, QualType(MemPtr->getClass(), 0),
5850 OnlyDeduced, Depth, Used);
5851 break;
5852 }
5853
5854 case Type::DependentSizedArray:
5855 MarkUsedTemplateParameters(Ctx,
5856 cast<DependentSizedArrayType>(T)->getSizeExpr(),
5857 OnlyDeduced, Depth, Used);
5858 // Fall through to check the element type
5859 LLVM_FALLTHROUGH[[gnu::fallthrough]];
5860
5861 case Type::ConstantArray:
5862 case Type::IncompleteArray:
5863 MarkUsedTemplateParameters(Ctx,
5864 cast<ArrayType>(T)->getElementType(),
5865 OnlyDeduced, Depth, Used);
5866 break;
5867
5868 case Type::Vector:
5869 case Type::ExtVector:
5870 MarkUsedTemplateParameters(Ctx,
5871 cast<VectorType>(T)->getElementType(),
5872 OnlyDeduced, Depth, Used);
5873 break;
5874
5875 case Type::DependentVector: {
5876 const auto *VecType = cast<DependentVectorType>(T);
5877 MarkUsedTemplateParameters(Ctx, VecType->getElementType(), OnlyDeduced,
5878 Depth, Used);
5879 MarkUsedTemplateParameters(Ctx, VecType->getSizeExpr(), OnlyDeduced, Depth,
5880 Used);
5881 break;
5882 }
5883 case Type::DependentSizedExtVector: {
5884 const DependentSizedExtVectorType *VecType
5885 = cast<DependentSizedExtVectorType>(T);
5886 MarkUsedTemplateParameters(Ctx, VecType->getElementType(), OnlyDeduced,
5887 Depth, Used);
5888 MarkUsedTemplateParameters(Ctx, VecType->getSizeExpr(), OnlyDeduced,
5889 Depth, Used);
5890 break;
5891 }
5892
5893 case Type::DependentAddressSpace: {
5894 const DependentAddressSpaceType *DependentASType =
5895 cast<DependentAddressSpaceType>(T);
5896 MarkUsedTemplateParameters(Ctx, DependentASType->getPointeeType(),
5897 OnlyDeduced, Depth, Used);
5898 MarkUsedTemplateParameters(Ctx,
5899 DependentASType->getAddrSpaceExpr(),
5900 OnlyDeduced, Depth, Used);
5901 break;
5902 }
5903
5904 case Type::ConstantMatrix: {
5905 const ConstantMatrixType *MatType = cast<ConstantMatrixType>(T);
5906 MarkUsedTemplateParameters(Ctx, MatType->getElementType(), OnlyDeduced,
5907 Depth, Used);
5908 break;
5909 }
5910
5911 case Type::DependentSizedMatrix: {
5912 const DependentSizedMatrixType *MatType = cast<DependentSizedMatrixType>(T);
5913 MarkUsedTemplateParameters(Ctx, MatType->getElementType(), OnlyDeduced,
5914 Depth, Used);
5915 MarkUsedTemplateParameters(Ctx, MatType->getRowExpr(), OnlyDeduced, Depth,
5916 Used);
5917 MarkUsedTemplateParameters(Ctx, MatType->getColumnExpr(), OnlyDeduced,
5918 Depth, Used);
5919 break;
5920 }
5921
5922 case Type::FunctionProto: {
5923 const FunctionProtoType *Proto = cast<FunctionProtoType>(T);
5924 MarkUsedTemplateParameters(Ctx, Proto->getReturnType(), OnlyDeduced, Depth,
5925 Used);
5926 for (unsigned I = 0, N = Proto->getNumParams(); I != N; ++I) {
5927 // C++17 [temp.deduct.type]p5:
5928 // The non-deduced contexts are: [...]
5929 // -- A function parameter pack that does not occur at the end of the
5930 // parameter-declaration-list.
5931 if (!OnlyDeduced || I + 1 == N ||
5932 !Proto->getParamType(I)->getAs<PackExpansionType>()) {
5933 MarkUsedTemplateParameters(Ctx, Proto->getParamType(I), OnlyDeduced,
5934 Depth, Used);
5935 } else {
5936 // FIXME: C++17 [temp.deduct.call]p1:
5937 // When a function parameter pack appears in a non-deduced context,
5938 // the type of that pack is never deduced.
5939 //
5940 // We should also track a set of "never deduced" parameters, and
5941 // subtract that from the list of deduced parameters after marking.
5942 }
5943 }
5944 if (auto *E = Proto->getNoexceptExpr())
5945 MarkUsedTemplateParameters(Ctx, E, OnlyDeduced, Depth, Used);
5946 break;
5947 }
5948
5949 case Type::TemplateTypeParm: {
5950 const TemplateTypeParmType *TTP = cast<TemplateTypeParmType>(T);
5951 if (TTP->getDepth() == Depth)
5952 Used[TTP->getIndex()] = true;
5953 break;
5954 }
5955
5956 case Type::SubstTemplateTypeParmPack: {
5957 const SubstTemplateTypeParmPackType *Subst
5958 = cast<SubstTemplateTypeParmPackType>(T);
5959 MarkUsedTemplateParameters(Ctx,
5960 QualType(Subst->getReplacedParameter(), 0),
5961 OnlyDeduced, Depth, Used);
5962 MarkUsedTemplateParameters(Ctx, Subst->getArgumentPack(),
5963 OnlyDeduced, Depth, Used);
5964 break;
5965 }
5966
5967 case Type::InjectedClassName:
5968 T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType();
5969 LLVM_FALLTHROUGH[[gnu::fallthrough]];
5970
5971 case Type::TemplateSpecialization: {
5972 const TemplateSpecializationType *Spec
5973 = cast<TemplateSpecializationType>(T);
5974 MarkUsedTemplateParameters(Ctx, Spec->getTemplateName(), OnlyDeduced,
5975 Depth, Used);
5976
5977 // C++0x [temp.deduct.type]p9:
5978 // If the template argument list of P contains a pack expansion that is
5979 // not the last template argument, the entire template argument list is a
5980 // non-deduced context.
5981 if (OnlyDeduced &&
5982 hasPackExpansionBeforeEnd(Spec->template_arguments()))
5983 break;
5984
5985 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I)
5986 MarkUsedTemplateParameters(Ctx, Spec->getArg(I), OnlyDeduced, Depth,
5987 Used);
5988 break;
5989 }
5990
5991 case Type::Complex:
5992 if (!OnlyDeduced)
5993 MarkUsedTemplateParameters(Ctx,
5994 cast<ComplexType>(T)->getElementType(),
5995 OnlyDeduced, Depth, Used);
5996 break;
5997
5998 case Type::Atomic:
5999 if (!OnlyDeduced)
6000 MarkUsedTemplateParameters(Ctx,
6001 cast<AtomicType>(T)->getValueType(),
6002 OnlyDeduced, Depth, Used);
6003 break;
6004
6005 case Type::DependentName:
6006 if (!OnlyDeduced)
6007 MarkUsedTemplateParameters(Ctx,
6008 cast<DependentNameType>(T)->getQualifier(),
6009 OnlyDeduced, Depth, Used);
6010 break;
6011
6012 case Type::DependentTemplateSpecialization: {
6013 // C++14 [temp.deduct.type]p5:
6014 // The non-deduced contexts are:
6015 // -- The nested-name-specifier of a type that was specified using a