assigned to @DougGregor

the parser rejects are all reduced to this simple test case:

struct foo bar;

'gcc -fsyntax-only' accepts this with no warning (weird..), while clang rejects it.

This is invalid code per C99 6.7p7.

Note that, for example,

extern struct foo bar;
void *p = &bar;

is legal and clang accepts this.

Doug, you made a comment indicating you thought this was legal. It is true that if this was a legal declaration this would be a tentative definition, however my reading is that this isn't a legal declaration.

Do you agree?

*** Bug llvm/llvm-bugzilla-archive#3349 has been marked as a duplicate of this bug. ***

the parser rejects are all reduced to this simple test case:

struct foo bar;

'gcc -fsyntax-only' accepts this with no warning (weird..), while clang
rejects it.

I think you reduced that a bit too much... that's actually a bug in gcc's "-fsyntax-only". Try "gcc -S -o /dev/null" instead.

Proper reduced testcase:

struct a x;
struct a {int x;};

And as far as I can tell, this is actually legal; 6.7p7 doesn't apply here because x has linkage.

Should be fixed by:

http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20090309/013735.html

mentioned in issue llvm/llvm-bugzilla-archive#3349