From c0dc76c2519b5700f5f9c081ed5a094775dd8780 Mon Sep 17 00:00:00 2001
From: Aaron Ballman <aaron@aaronballman.com>
Date: Mon, 31 Aug 2015 21:54:42 +0000
Subject: [PATCH] Allow the static assert clang-tidy checker to run over C
 code.

llvm-svn: 246495
---
 .../clang-tidy/misc/StaticAssertCheck.cpp     |  7 +++--
 .../test/clang-tidy/misc-static-assert.c      | 27 +++++++++++++++++++
 2 files changed, 30 insertions(+), 4 deletions(-)
 create mode 100644 clang-tools-extra/test/clang-tidy/misc-static-assert.c

diff --git a/clang-tools-extra/clang-tidy/misc/StaticAssertCheck.cpp b/clang-tools-extra/clang-tidy/misc/StaticAssertCheck.cpp
index 0828059f494a..7b596cdf6a72 100644
--- a/clang-tools-extra/clang-tidy/misc/StaticAssertCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/StaticAssertCheck.cpp
@@ -27,10 +27,9 @@ StaticAssertCheck::StaticAssertCheck(StringRef Name, ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context) {}
 
 void StaticAssertCheck::registerMatchers(MatchFinder *Finder) {
-  // FIXME: I don't see why this checker couldn't also be interesting for
-  // _Static_assert in C11, or static_assert if <assert.h> has been included, 
-  // but it is currently only enabled for C++11. Investigate.
-  if (!getLangOpts().CPlusPlus11)
+  // This checker only makes sense for languages that have static assertion
+  // capabilities: C++11 and C11.
+  if (!(getLangOpts().CPlusPlus11 || getLangOpts().C11))
     return;
 
   auto IsAlwaysFalse = expr(ignoringParenImpCasts(
diff --git a/clang-tools-extra/test/clang-tidy/misc-static-assert.c b/clang-tools-extra/test/clang-tidy/misc-static-assert.c
new file mode 100644
index 000000000000..aa0b7ee2b9f5
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/misc-static-assert.c
@@ -0,0 +1,27 @@
+// RUN: %python %S/check_clang_tidy.py %s misc-static-assert %t -- -std=c11
+// RUN: clang-tidy %s -checks=-*,misc-static-assert -- -std=c99 | count 0
+
+void abort() {}
+#ifdef NDEBUG
+#define assert(x) 1
+#else
+#define assert(x)                                                              \
+  if (!(x))                                                                    \
+  abort()
+#endif
+
+void f(void) {
+  int x = 1;
+  assert(x == 0);
+  // CHECK-FIXES: {{^  }}assert(x == 0);
+
+  #define static_assert(x, msg) _Static_assert(x, msg)
+  assert(11 == 5 + 6);
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: found assert() that could be
+  // CHECK-FIXES: {{^  }}static_assert(11 == 5 + 6, "");
+  #undef static_assert
+
+  assert(10 == 5 + 5);
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: found assert() that could be
+  // CHECK-FIXES: {{^  }}static_assert(10 == 5 + 5, "");
+}