Incomplete checks for pointer addition

Testcase:
int a; int (*b) = &a+1;
Should give an error in sema, but clang lets it through.

Pretty easy to fix.

-Eli

Here's a fix. It's a little longer than I'd like, but I'm not sure if
there's anything I can do there.

-Eli

pointeraddtypecheck.txt (1.79 KB)

pointeraddtypecheck.txt (1.79 KB)