llvm-project/clang/test/CXX/class/class.mem/p5-0x.cpp

// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s 

int f();

struct S 
{
  int a = f(); // ok
  int b = g(); // expected-error {{use of undeclared identifier 'g'}}
};