getCalleeDecl() returns NULL in edge case.

[llvmbot]

Bugzilla Link	10804
Version	trunk
OS	Linux
Reporter	LLVM Bugzilla Contributor
CC	@jryans

Extended Description

getCalleeDecl() returns NULL in a function call to a method pointer, if the method pointer is passed as a template parameter. For example:

template<void (UnFoo::*methptr)()>
class MCaller {
public:
static void call_method_ptr(UnFoo *f) {
// FIXME: Possible Clang bug:
// getCalleeDecl() returns NULL in the following case:
(f->*methptr)();
}
};

void call_method_ptr_inst(UnFoo* f) {
MCaller<&UnFoo::foo>::call_method_ptr(f);
}

[llvmbot]

Which decl did you want, though? The CalleeExpr is the whole "(f->*methptr)" expression (including the parenthesis), which doesn't have a matching Decl.

[llvmbot]

Perhaps this is expected behavior. However, I would intuitively expect the template version to behave similarly to the following non-template version:

void call_method_ptr2(UnFoo* f, void (UnFoo::*methptr)()) {
(f->*methptr)();
}

In the code above, getCalleeDecl() on the method call returns the declaration of methodptr. In the template case, however, which is syntactically very similar, it returns NULL.

In this particular case, I would expect the getCalleeDecl() on the instantiated template to return Unfoo::foo.