Fix crash in redundant-void-arg check.

Summary:
When applying this check to the unit tests, it would hit an assertion:
llvm/tools/clang/lib/Lex/Lexer.cpp:1056: clang::SourceLocation clang::Lexer::getSourceLocation(const char*, unsigned int) const: Assertion `PP && "This doesn't work on raw lexers"' failed.

Reviewers: klimek, LegalizeAdulthood, alexfh

Subscribers: cfe-commits, alexfh

Differential Revision: http://reviews.llvm.org/D14204

llvm-svn: 251792
diff --git a/clang-tools-extra/test/clang-tidy/modernize-redundant-void-arg.cpp b/clang-tools-extra/test/clang-tidy/modernize-redundant-void-arg.cpp
index dd758bc..b0bdeae 100644
--- a/clang-tools-extra/test/clang-tidy/modernize-redundant-void-arg.cpp
+++ b/clang-tools-extra/test/clang-tidy/modernize-redundant-void-arg.cpp
@@ -417,3 +417,19 @@
   // CHECK-MESSAGES: [[@LINE-2]]:45: warning: {{.*}} in lambda expression
   // CHECK-FIXES: {{^  }}auto void_returner = []() -> void (*)() { return f1; };{{$}}
 }
+
+#define M(x) x
+
+M(void inmacro(void) {})
+// CHECK-MESSAGES: :[[@LINE-1]]:16: warning: {{.*}} in function definition
+// CHECK-FIXES: M(void inmacro() {})
+
+#define F(A, B)        \
+  struct F_##A##_##B { \
+    F_##A##_##B(void); \
+  };                   \
+  F_##A##_##B::F_##A##_##B(void)
+
+F(Foo, Bar) {
+
+}