[clang-format] Don't annotate left brace of struct as FunctionLBrace

[owenpan]

Summary

Related to a02c3af9f19d. Fixes https://github.com/llvm/llvm-project/issues/61700.

[MyDeveloperDay]

LGTM

[owenpan]

Handles consecutive attributes too.

clang/lib/Format/UnwrappedLineParser.cpp

static void markOptionalBraces(FormatToken *LeftBrace) {
   LeftBrace->Optional = true;
   RightBrace->Optional = true;
 }
 
 void UnwrappedLineParser::handleAttributes() {
   // Handle AttributeMacro, e.g. `if (x) UNLIKELY`.
   if (FormatTok->is(TT_AttributeMacro))
     nextToken();
+  if (FormatTok->is(tok::l_square))
     handleCppAttributes();
 }
 
 bool UnwrappedLineParser::handleCppAttributes() {
   // Handle [[likely]] / [[unlikely]] attributes.
-  if (FormatTok->is(tok::l_square) && tryToParseSimpleAttribute()) {
-    parseSquare();
-    return true;
-  }
-  return false;
-}
+  assert(FormatTok->is(tok::l_square));
+  if (!tryToParseSimpleAttribute())
+    return false;
 
 /// Returns whether \c Tok begins a block.
 bool UnwrappedLineParser::isBlockBegin(const FormatToken &Tok) const {
   // FIXME: rename the function or make
   // Tok.isOneOf(tok::l_brace, TT_MacroBlockBegin) work.
   return Style.isVerilog() ? Keywords.isVerilogBegin(Tok)
                            : Tok.is(tok::l_brace);
 }
void UnwrappedLineParser::parseJavaEnumBody() {
   nextToken();
   --Line->Level;
   addUnwrappedLine();
 }
 
 void UnwrappedLineParser::parseRecord(bool ParseAsExpr) {
   const FormatToken &InitialToken = *FormatTok;
   nextToken();
-  handleAttributes();
 
   // The actual identifier can be a nested name specifier, and in macros
   // it is often token-pasted.
+  // An [[attribute]] can be before the identifier.
   while (FormatTok->isOneOf(tok::identifier, tok::coloncolon, tok::hashhash,
                             tok::kw___attribute, tok::kw___declspec,
-                            tok::kw_alignas) ||
+                            tok::kw_alignas, tok::l_square) ||
          ((Style.Language == FormatStyle::LK_Java || Style.isJavaScript()) &&
           FormatTok->isOneOf(tok::period, tok::comma))) {
     if (Style.isJavaScript() &&
         FormatTok->isOneOf(Keywords.kw_extends, Keywords.kw_implements)) {
       // JavaScript/TypeScript supports inline object types in
       // extends/implements positions:
       //     class Foo implements {bar: number} { }
       nextToken();
       if (FormatTok->is(tok::l_brace)) {
         tryToParseBracedList();
         continue;
       }
     }
+    if (FormatTok->is(tok::l_square))
+      handleCppAttributes();
     bool IsNonMacroIdentifier =
         FormatTok->is(tok::identifier) &&
         FormatTok->TokenText != FormatTok->TokenText.upper();
     nextToken();
     // We can have macros in between 'class' and the class name.
-    if (!IsNonMacroIdentifier) {
-      if (FormatTok->is(tok::l_paren)) {
-        parseParens();
-      }
-    }
-  }
+    if (!IsNonMacroIdentifier && FormatTok->is(tok::l_paren))
 
   // Note that parsing away template declarations here leads to incorrectly
   // accepting function declarations as record declarations.
   // In general, we cannot solve this problem. Consider:
   // class A<int> B() {}
   // which can be a function definition or a class definition when B() is a
   // macro. If we find enough real-world cases where this is a problem, we
   // can parse for the 'template' keyword in the beginning of the statement,

clang/unittests/Format/FormatTest.cpp

verifyFormat("for (;;) {\n"
                "}",
                Style);
 
   verifyFormat("class [[deprecated(\"\")]] C {\n"
                "  int i;\n"
                "};",
                Style);
 
+  verifyFormat("struct EXPORT_MACRO [[nodiscard]] C {\n"
+               "  int i;\n"
+               "};",
+               Style);
+
   verifyIncompleteFormat("class C final [[deprecated(l]] {});", Style);
 
   // These tests are here to show a problem that may not be easily
   // solved, our implementation to remove semicolons is only as good
   // as our FunctionLBrace detection and this fails for empty braces
   // because we can't distringuish this from a bracelist.
   // We will enable when that is resolved.
 #if 0

clang/unittests/Format/TokenAnnotatorTest.cpp

TEST_F(TokenAnnotatorTest, UnderstandsClasses) {
   EXPECT_EQ(Tokens.size(), 17u) << Tokens;
   EXPECT_TOKEN(Tokens[10], tok::l_brace, TT_ClassLBrace);
 }
 
 TEST_F(TokenAnnotatorTest, UnderstandsStructs) {
   auto Tokens = annotate("struct S {};");
   EXPECT_EQ(Tokens.size(), 6u) << Tokens;
   EXPECT_TOKEN(Tokens[2], tok::l_brace, TT_StructLBrace);
+
+  Tokens = annotate("struct EXPORT_MACRO [[nodiscard]] C { int i; };");
+  EXPECT_EQ(Tokens.size(), 15u) << Tokens;
+  EXPECT_TOKEN(Tokens[8], tok::l_brace, TT_StructLBrace);
 }
 
 TEST_F(TokenAnnotatorTest, UnderstandsUnions) {
   auto Tokens = annotate("union U {};");
   EXPECT_EQ(Tokens.size(), 6u) << Tokens;
   EXPECT_TOKEN(Tokens[2], tok::l_brace, TT_UnionLBrace);
 
   Tokens = annotate("union U { void f() { return; } };");