[clang-format] Fix invalid code generation with comments in lambda

[owenpan]

Summary

Fixes:
https://github.com/llvm/llvm-project/issues/51234
https://github.com/llvm/llvm-project/issues/54496

[curdeius]

Great! LGTM.

clang/lib/Format/TokenAnnotator.cpp

if (Current->is(TT_LineComment)) {
           }
         }
       }
     } else if (Current->SpacesRequiredBefore == 0 &&
                spaceRequiredBefore(Line, *Current)) {
       Current->SpacesRequiredBefore = 1;
     }
 
+    const auto &Children = Prev->Children;
+    if (!Children.empty() && Children.back()->Last->is(TT_LineComment)) {
+      Current->MustBreakBefore = true;
+    } else {
       Current->MustBreakBefore =
           Current->MustBreakBefore || mustBreakBefore(Line, *Current);
-
       if (!Current->MustBreakBefore && InFunctionDecl &&
           Current->is(TT_FunctionDeclarationName))
         Current->MustBreakBefore = mustBreakForReturnType(Line);
+    }
 
     Current->CanBreakBefore =
         Current->MustBreakBefore || canBreakBefore(Line, *Current);
     unsigned ChildSize = 0;
     if (Prev->Children.size() == 1) {
       FormatToken &LastOfChild = *Prev->Children[0]->Last;
       ChildSize = LastOfChild.isTrailingComment() ? Style.ColumnLimit
                                                   : LastOfChild.TotalLength + 1;

clang/unittests/Format/FormatTest.cpp

verifyFormat("auto k = []() /* comment */ /* comment */ { return; }",
                LLVMWithBeforeLambdaBody);
   verifyFormat("auto k = []() // X\n"
                "{ return; }",
                LLVMWithBeforeLambdaBody);
   verifyFormat(
       "auto k = []() // XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\n"
       "{ return; }",
       LLVMWithBeforeLambdaBody);
+
+  LLVMWithBeforeLambdaBody.ColumnLimit = 0;
+
+  verifyFormat("foo([]()\n"
+               "    {\n"
+               "      bar();    //\n"
+               "      return 1; // comment\n"
+               "    }());",
+               "foo([]() {\n"
+               "  bar(); //\n"
+               "  return 1; // comment\n"
+               "}());",
+               LLVMWithBeforeLambdaBody);
+  verifyFormat("foo(\n"
+               "    1, MACRO {\n"
+               "      baz();\n"
+               "      bar(); // comment\n"
+               "    },\n"
+               "    []() {});",
+               "foo(\n"
+               "  1, MACRO { baz(); bar(); // comment\n"
+               "  }, []() {}\n"
+               ");",
+               LLVMWithBeforeLambdaBody);
 }
 
 TEST_F(FormatTest, EmptyLinesInLambdas) {
   verifyFormat("auto lambda = []() {\n"
                "  x(); //\n"
                "};",
                "auto lambda = []() {\n"
                "\n"