clang-format: Fix column layout with a comment in the last line.

Before:
  int aaaaa[] = {
      1, 2,
      3, // comment
      4, 5,
      6  // comment
  };

After:
  int aaaaa[] = {
      1, 2, 3, // comment
      4, 5, 6  // comment
  };

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@242299 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Format/FormatToken.cpp

@@ -183,7 +183,8 @@ void CommaSeparatedList::precomputeFormattingInfos(const FormatToken *Token) {
       ItemEnd = Token->MatchingParen;
       const FormatToken *NonCommentEnd = ItemEnd->getPreviousNonComment();
       ItemLengths.push_back(CodePointsBetween(ItemBegin, NonCommentEnd));
-      if (Style.Cpp11BracedListStyle) {
+      if (Style.Cpp11BracedListStyle &&
+          !ItemEnd->Previous->isTrailingComment()) {
         // In Cpp11 braced list style, the } and possibly other subsequent
         // tokens will need to stay on a line with the last element.
         while (ItemEnd->Next && !ItemEnd->Next->CanBreakBefore)

unittests/Format/FormatTest.cpp

@@ -6307,6 +6307,11 @@ TEST_F(FormatTest, FormatsBracedListsInColumnLayout) {
                "    1111111111, 2222222222, 33333333333, 4444444444, //\n"
                "    111111111,  222222222,  3333333333,  444444444,  //\n"
                "    11111111,   22222222,   333333333,   44444444};");
+  // Trailing comment in the last line.
+  verifyFormat("int aaaaa[] = {\n"
+               "    1, 2, 3, // comment\n"
+               "    4, 5, 6  // comment\n"
+               "};");
 
   // With nested lists, we should either format one item per line or all nested
   // lists one on line.