[Sema] Allow implicit conversions of &overloaded_fn in C.

Also includes a minor ``enable_if`` docs update.

Currently, our address-of overload machinery will only allow implicit
conversions of overloaded functions to void* in C. For example:

```
void f(int) __attribute__((overloadable));
void f(double) __attribute__((overloadable, enable_if(0, "")));

void *fp = f; // OK. This is C and the target is void*.
void (*fp2)(void) = f; // Error. This is C, but the target isn't void*.
```

This patch makes the assignment of `fp2` select the `f(int)` overload,
rather than emitting an error (N.B. you'll still get a warning about the
`fp2` assignment if you use -Wincompatible-pointer-types).

Differential Revision: http://reviews.llvm.org/D13704

llvm-svn: 264132

1 files changed, 2 insertions, 2 deletions

diff --git a/clang/test/Sema/pass-object-size.c b/clang/test/Sema/pass-object-size.c
index 6f375c0e94d..ddfbbd5fc4e 100644
--- a/clang/test/Sema/pass-object-size.c
+++ b/clang/test/Sema/pass-object-size.c
@@ -38,8 +38,8 @@ void FunctionPtrs() {
   void (*p)(void *) = NotOverloaded; //expected-error{{cannot take address of function 'NotOverloaded' because parameter 1 has pass_object_size attribute}}
   void (*p2)(void *) = &NotOverloaded; //expected-error{{cannot take address of function 'NotOverloaded' because parameter 1 has pass_object_size attribute}}
 
-  void (*p3)(void *) = IsOverloaded; //expected-error{{initializing 'void (*)(void *)' with an expression of incompatible type '<overloaded function type>'}} expected-note@-6{{candidate address cannot be taken because parameter 1 has pass_object_size attribute}} expected-note@-5{{type mismatch}}
-  void (*p4)(void *) = &IsOverloaded; //expected-error{{initializing 'void (*)(void *)' with an expression of incompatible type '<overloaded function type>'}} expected-note@-7{{candidate address cannot be taken because parameter 1 has pass_object_size attribute}} expected-note@-6{{type mismatch}}
+  void (*p3)(void *) = IsOverloaded; //expected-warning{{incompatible pointer types initializing 'void (*)(void *)' with an expression of type '<overloaded function type>'}} expected-note@-6{{candidate address cannot be taken because parameter 1 has pass_object_size attribute}} expected-note@-5{{type mismatch}}
+  void (*p4)(void *) = &IsOverloaded; //expected-warning{{incompatible pointer types initializing 'void (*)(void *)' with an expression of type '<overloaded function type>'}} expected-note@-7{{candidate address cannot be taken because parameter 1 has pass_object_size attribute}} expected-note@-6{{type mismatch}}
 
   void (*p5)(char *) = IsOverloaded;
   void (*p6)(char *) = &IsOverloaded;