[clang-format] Handle trailing comment for InsertBraces

[curdeius]

LGTM.

[HazardyKnusperkeks]

clang/lib/Format/UnwrappedLineParser.cpp

2338–2339

So basically one would just need a Line.isComment() or so? The lastNonComment is not important, right?

[owenpan]

• Simplified the code that backtracks to the token which the right braces are to be inserted after.
• Added a missing newline in the new testcase.

[owenpan]

clang/lib/Format/UnwrappedLineParser.cpp

2338–2339

We don't really need a pointer to the last non-comment token here as we would return the last token of the line, but the pointer is still needed for the left brace above.

[owenpan]

clang/lib/Format/UnwrappedLineParser.cpp

2338–2339

We have to try to find either the first or the last non-comment token in L to determine if it's a comment line, for L can be something like:

/* comment */ f(); // comment

clang/lib/Format/Format.cpp

for (AnnotatedLine *Line : Lines) {
            Token = Token->Next) {
         if (Token->BraceCount == 0)
           continue;
         std::string Brace;
         if (Token->BraceCount < 0) {
           assert(Token->BraceCount == -1);
           Brace = '{';
         } else {
-          Brace = std::string(Token->BraceCount, '}');
+          Brace = '\n' + std::string(Token->BraceCount, '}');
         }
         Token->BraceCount = 0;
         const auto Start = Token->Tok.getEndLoc();
         cantFail(Result.add(tooling::Replacement(SourceMgr, Start, 0, Brace)));
       }
     }
   }
 };

clang/lib/Format/UnwrappedLineParser.cpp

void UnwrappedLineParser::parseUnbracedBody(bool CheckEOF) {
 
   addUnwrappedLine();
   ++Line->Level;
   parseStructuralElement();
 
   if (Tok) {
     assert(!Line->InPPDirective);
     Tok = nullptr;
     for (const auto &L : llvm::reverse(*CurrentLines)) {
-      if (!L.InPPDirective) {
-        Tok = getLastNonComment(L);
-        if (Tok)
-          break;
+      if (!L.InPPDirective && getLastNonComment(L)) {
+        Tok = L.Tokens.back().Tok;
       }
     }
     assert(Tok);
     ++Tok->BraceCount;
   }
 
   if (CheckEOF && FormatTok->is(tok::eof))
     addUnwrappedLine();

clang/unittests/Format/FormatTest.cpp

verifyFormat("if (a) { // comment\n"
                "  f();\n"
                "}",
                "if (a) // comment\n"
                "  // comment\n"
                "  f();",
                Style);
 
   verifyFormat("if (a) {\n"
+               "  f(); // comment\n"
+               "}",
+               "if (a)\n"
+               "  f(); // comment",
+               Style);
+
+  verifyFormat("if (a) {\n"
                "  f();\n"
                "}\n"
                "#undef A\n"
                "#undef B",
                "if (a)\n"
                "  f();\n"
                "#undef A\n"
                "#undef B",