False positive -Wreturn-type for bitfields

[marxin]

The following test-case is wrongly marked with -Wreturn-type:

struct A
{
  unsigned int val: 1;
};

int foo(struct A *a)
{
  switch (a->val)
  {
    case 0:
      return 123;
    case 1:
      return 456;
  }
}

$ clang unreachable.c  -Werror=return-type -c
unreachable.c:15:1: error: non-void function does not return a value in all control paths [-Werror,-Wreturn-type]
}
^
1 error generated.

Note GCC accepts the code:

gcc unreachable.c  -Werror=return-type -c

[llvmbot]

@llvm/issue-subscribers-clang-frontend