Suppress -Wshadow / -Wold-style-cast expanded from system header macros

Thanks to Jonathan Sauer for providing initial test cases.

Fixes PR16093 and PR18147.

llvm-svn: 197150

1 files changed, 35 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/warn-sysheader-macro.cpp b/clang/test/SemaCXX/warn-sysheader-macro.cpp
new file mode 100644
index 00000000000..c88461720ad
--- /dev/null
+++ b/clang/test/SemaCXX/warn-sysheader-macro.cpp
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 -verify -fsyntax-only -Wshadow -Wold-style-cast %s
+
+// Test that macro expansions from system headers don't trigger 'syntactic'
+// warnings that are not actionable.
+
+#ifdef IS_SYSHEADER
+#pragma clang system_header
+
+#define SANITY(a) (a / 0)
+
+#define SHADOW(a) __extension__({ int v = a; v; })
+
+#define OLD_STYLE_CAST(a) ((int) (a))
+
+#else
+
+#define IS_SYSHEADER
+#include __FILE__
+
+void testSanity() {
+  // Validate that the test is set up correctly
+  int i = SANITY(0); // expected-warning {{division by zero is undefined}}
+}
+
+void PR16093() {
+  // no -Wshadow in system macro expansion
+  int i = SHADOW(SHADOW(1));
+}
+
+void PR18147() {
+  // no -Wold_style_cast in system macro expansion
+  int i = OLD_STYLE_CAST(0);
+}
+
+#endif