[cfe-dev] Clang ignores nonnull attributes on pointer-to-member-function declarations

[Tom Honermann]

Clang (3.4-trunk) ignores nonnull attributes on 
pointer-to-member-function declarations.

A test case follows.  Recent versions of gcc [1] allow nonnull 
attributes on pointer-to-member-function declarations.  Is there any 
reason that Clang shouldn't also permit these?  If not, I'll open a new 
PR for this.

Tom.

[1] gcc 5.0, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60765

$ cat t.cpp
struct S;
void (S::*pmf)(int *p1)
     __attribute__((nonnull));
void f(S *s) {
     (s->*pmf)(0);
}

# Clang trunk emits a warning for the presence of the attribute, but not
# for passing a null argument:
$ clang -c t.cpp
t.cpp:3:20: warning: 'nonnull' attribute only applies to functions, 
methods, and parameters [-Wignored-attributes]
     __attribute__((nonnull));
                    ^
1 warning generated.

# gcc (6.0) accepts the nonnull attribute and emits a warning for
# passing a null argument:
$ gcc -Wall -c t.cpp
t.cpp: In function ‘void f(S*)’:
t.cpp:5:16: warning: null argument where non-null required (argument 2) 
[-Wnonnull]
      (s->*pmf)(0);
                 ^