[PATCH] Fix crash when using __if_exists in C mode

[Nico Rieck]

From ec3565a832dba9a4ab105cdeb09f308be3179ced Mon Sep 17 00:00:00 2001
From: Nico Rieck <nico.rieck at gmail.com>
Date: Sun, 16 Nov 2014 10:35:04 +0100
Subject: [PATCH] Fix crash when using __if_exists in C mode

---
 lib/Parse/Parser.cpp       |  5 +--
 test/Parser/ms-if-exists.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 90 insertions(+), 2 deletions(-)
 create mode 100644 test/Parser/ms-if-exists.c

diff --git a/lib/Parse/Parser.cpp b/lib/Parse/Parser.cpp
index 2bac56c..4ddc5bf 100644
--- a/lib/Parse/Parser.cpp
+++ b/lib/Parse/Parser.cpp
@@ -1788,8 +1788,9 @@ bool Parser::ParseMicrosoftIfExistsCondition(IfExistsCondition& Result) {
   }
   
   // Parse nested-name-specifier.
-  ParseOptionalCXXScopeSpecifier(Result.SS, ParsedType(), 
-                                 /*EnteringContext=*/false);
+  if (getLangOpts().CPlusPlus)
+    ParseOptionalCXXScopeSpecifier(Result.SS, ParsedType(),
+                                   /*EnteringContext=*/false);
 
   // Check nested-name specifier.
   if (Result.SS.isInvalid()) {
diff --git a/test/Parser/ms-if-exists.c b/test/Parser/ms-if-exists.c
new file mode 100644
index 0000000..7dd2054
--- /dev/null
+++ b/test/Parser/ms-if-exists.c
@@ -0,0 +1,87 @@
+// RUN: %clang_cc1 %s -fsyntax-only -Wmicrosoft -verify -fms-extensions
+// expected-no-diagnostics
+
+struct Type {
+};
+
+void test_if_exists_stmts() {
+  int b = 0;
+  __if_exists(Type) {
+    b++;
+    b++;
+  }
+  __if_exists(Type_not) {
+    this will not compile.
+  }
+  __if_not_exists(Type) {
+    this will not compile.
+  }
+  __if_not_exists(Type_not) {
+    b++;
+    b++;
+  }
+}
+
+int if_exists_creates_no_scope() {
+  __if_exists(Type) {
+    int x;  // 'x' is declared in the parent scope.
+  }
+  __if_not_exists(Type_not) {
+    x++;
+  }
+  return x;
+}
+
+__if_exists(Type) {
+  int var23;
+}
+
+__if_exists(Type_not) {
+  this will not compile.
+}
+
+__if_not_exists(Type) {
+  this will not compile.
+}
+
+__if_not_exists(Type_not) {
+  int var244;
+}
+
+void test_if_exists_init_list() {
+
+  int array1[] = {
+    0,
+    __if_exists(Type) {2, }
+    3
+  };
+
+  int array2[] = {
+    0,
+    __if_exists(Type_not) { this will not compile }
+    3
+  };
+
+  int array3[] = {
+    0,
+    __if_not_exists(Type_not) {2, }
+    3
+  };
+
+  int array4[] = {
+    0,
+    __if_not_exists(Type) { this will not compile }
+    3
+  };
+
+}
+
+
+void test_nested_if_exists() {
+  __if_exists(Type) {
+    int x = 42;
+    __if_not_exists(Type_not) {
+      x++;
+    }
+  }
+}
-- 
1.9.4.msysgit.2