[ObjC]Type defined as 'id' is not recognized as a valid object type.

[llvmbot]

Bugzilla Link	3932
Resolution	FIXED
Resolved on	Mar 12, 2010 00:57
Version	unspecified
OS	All
Reporter	LLVM Bugzilla Contributor
CC	@tkremenek

Extended Description

When defining a new type as an id, this new type is not recognized as a valid id (objc object) by clang.
This is particulary annoying when this type is used where an objc object is required, as clang will report an error where gcc does not.

------------- test.m --------------
typedef id BYObjectIdentifier;

@​interface Foo {
void *isa;
}

@​property(copy) BYObjectIdentifier identifier;

@​end

---

clang -c test.m
error: property with 'copy' attribute must be of object type
@​property(copy) BYObjectIdentifier identifier;

[lattner]

This is an interesting bug. It boils down to being an issue in ASTContext::isObjCObjectPointerType. Basically, we only allow things that are exactly equal to the 'id' typedef:

// Check to see if this is 'id' or 'Class', both of which are typedefs for
// pointer types. This looks for the typedef specifically, not for the
// underlying type.
if (Ty.getUnqualifiedType() == getObjCIdType() ||
Ty.getUnqualifiedType() == getObjCClassType())
return true;

In this case, we have a typedef of the id typedef of the struct pointer. Perhaps this code should change to look at the canonical (pointer to struct) type, and just verify that it is the expected struct tag?

[tkremenek]

Steve: Can you take a look at this when you have time?

[lattner]

Fixed:
http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20090406/015435.html