llvm/clang/test/Index/preamble-conditionals-inverted.cpp

// RUN: env CINDEXTEST_EDITING=1 c-index-test -test-load-source-reparse 5 \
// RUN:                                       local -std=c++14 %s 2>&1 \
// RUN: | FileCheck %s --implicit-check-not "error:"
#ifdef FOO_H

void foo() {}

#endif

int foo() { return 0; }