assigned to @mgehre

More information is needed.

0. Stack trace, please. Better if you run the assertions-enabled clang-tidy
1. Please figure out which check does that.
2. How does your compilation database (compile_commands.json, I guess) look like? Can you reproduce the issue using fixed compilation database (clang-tidy file.cpp -- )?
3. Does this happen without the -extra-arg="-D__clang_tidy__"?

Reproduction info + stracktrace

0. See attachment
1. I've tried, though as I use -check=*,-dontwant1,-dontwant2..., it's not that easy, though it should at least be in the commits of the last few weeks (2 or 3), as I try keeping up with the trunk.
2. I'll add it too in attachment
3. Yes it does, the -extra-arg is only to workaround other clang-tidy bugs.

0. See attachment
   1 [details]. I've tried, though as I use -check=*,-dontwant1,-dontwant2...,
   it's not that easy, though it should at least be in the commits of the last
   few weeks (2 or 3), as I try keeping up with the trunk.
1. I'll add it too in attachment
   3 [details]. Yes it does, the -extra-arg is only to workaround other
   clang-tidy bugs.

Thanks, I was able to reproduce this:

$ cat /tmp/q.cc
#include
$ clang-tidy -checks=-*,misc-misplaced-widening-cast /tmp/q.cc -- -std=c++11
PC: @ 0x7fad758a5720 (unknown) clang::ast_type_traits::ASTNodeKind::getFromNode()
@ 0x7fad75e052d7 928 FailureSignalHandler()
@ 0x7fad738193d0 1504 __restore_rt
@ 0x7fad74f5c083 32 clang::ast_matchers::internal::DynTypedMatcher::matchesNoKindCheck()
...

The problem is in the recently added hasReturnValue matcher:

AST_MATCHER_P(ReturnStmt, hasReturnValue, internal::Matcher,
InnerMatcher) {
return InnerMatcher.matches(*Node.getRetValue(), Finder, Builder);
}

It dereferences Node.getRetValue() which can be null. The fix should be committed soon: http://reviews.llvm.org/D18991

The mentioned fix is committed in http://reviews.llvm.org/rL266043