clang-format: Fix corner case with comment in ctor initializer.

Formatting:
  Constructor() :
      // Comment forcing unwanted break.
      aaaa(aaaa) {}

Before:
  Constructor()
      :
        // Comment forcing unwanted break.
        aaaa(aaaa) {}

After:
  Constructor()
      : // Comment forcing unwanted break.
        aaaa(aaaa) {}

llvm-svn: 199107

clang/lib/Format/TokenAnnotator.cpp

@@ -1436,6 +1436,7 @@ bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
                                      const FormatToken &Right) {
   if (Right.is(tok::comment)) {
     return Right.Previous->BlockKind != BK_BracedInit &&
+           Right.Previous->Type != TT_CtorInitializerColon &&
            Right.NewlinesBefore > 0;
   } else if (Right.Previous->isTrailingComment() ||
              (Right.isStringLiteral() && Right.Previous->isStringLiteral())) {

clang/unittests/Format/FormatTest.cpp

@@ -2896,6 +2896,13 @@ TEST_F(FormatTest, ConstructorInitializers) {
                "    : aaaaa(aaaaaaaaaaaaaaaaaaaaaa, aaaaaaaaaaaaaaaaaaaaaa,\n"
                "            aaaaaaaaaaaaaaaaaaaaaa) {}",
                OnePerLine);
+
+  EXPECT_EQ("Constructor()\n"
+            "    : // Comment forcing unwanted break.\n"
+            "      aaaa(aaaa) {}",
+            format("Constructor() :\n"
+                   "    // Comment forcing unwanted break.\n"
+                   "    aaaa(aaaa) {}"));
 }
 
 TEST_F(FormatTest, MemoizationTests) {