Crash during AST destruction

[akyrtzi]

Bugzilla Link	3020
Resolution	FIXED
Resolved on	Mar 12, 2010 00:59
Version	unspecified
OS	Windows XP
CC	@tkremenek

Extended Description

Compile with -fsyntax-only -x=c++

void f() {
class A {};
A;
}

[llvmbot]

The
A;
is taken as a second declaration of the local class, but without a new Decl. This leads to a double-free.
Sema::ParsedFreeStandingDeclSpec is very weird. I think there's something major wrong with this.

[llvmbot]

Why does 'TypeTy* Sema::isTypeName(...)' return a Decl? This is a type mismatch of some kind.

[llvmbot]

Seems like ParsedFreeStandingDeclSpec doesn't distinguish between

class A;

and

A;

However, while the first had its own TagDecl created while parsing the DeclSpec, the latter got an existing one from token annotation. It blindly returns it, and it's further passed to ActOnDeclStmt, which takes ownership - but someone else already owns it!

In C, only a typedef name could be standalone, and the dyn_cast to TagDecl catches that. However, in C++ a tag name can be standalone, too, and this method just can't handle it.

I think I know how to fix this, but I can't do it at midnight.

[llvmbot]

Fixed:
http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20081222/010522.html