[clang-tidy] Fix bug in modernize-loop-convert check.

http://reviews.llvm.org/D12186

Patch by Angel Garcia!

llvm-svn: 245561

clang-tools-extra/clang-tidy/modernize/LoopConvertCheck.cpp

@@ -337,8 +337,9 @@ static StringRef getStringFromRange(SourceManager &SourceMgr,
                                     const LangOptions &LangOpts,
                                     SourceRange Range) {
   if (SourceMgr.getFileID(Range.getBegin()) !=
-      SourceMgr.getFileID(Range.getEnd()))
-    return nullptr;
+      SourceMgr.getFileID(Range.getEnd())) {
+    return StringRef(); // Empty string.
+  }
 
   return Lexer::getSourceText(CharSourceRange(Range, true), SourceMgr,
                               LangOpts);

clang-tools-extra/test/clang-tidy/Inputs/modernize-loop-convert/structures.h

@@ -176,4 +176,15 @@ struct RValueDerefContainer {
   iterator begin() const;
   iterator end() const;
 };
+
+namespace Macros {
+
+struct MacroStruct {
+  int arr[10];
+};
+static MacroStruct *MacroSt;
+#define CONT MacroSt->
+
+} // namespace Macros
+
 #endif  // STRUCTURES_H

clang-tools-extra/test/clang-tidy/modernize-loop-convert-extra.cpp

@@ -605,4 +605,25 @@ void different_type() {
   }
 }
 
+} // namespace SingleIterator
+
+
+namespace Macros {
+
+const int N = 10;
+int arr[N];
+
+void messing_with_macros() {
+  for (int i = 0; i < N; ++i) {
+    printf("Value: %d\n", arr[i]);
   }
+  // CHECK-MESSAGES: :[[@LINE-3]]:3: warning: use range-based for loop instead
+  // CHECK-FIXES: for (auto & elem : arr) {
+  // CHECK-FIXES-NEXT:  printf("Value: %d\n", elem);
+
+  for (int i = 0; i < N; ++i) {
+    printf("Value: %d\n", CONT arr[i]);
+  }
+}
+
+} // namespace Macros