[clang-format] Fix a bug in annotating arrows after init braces (#119958)

Fixes #59066.

Author: owenca

clang/lib/Format/TokenAnnotator.cpp

@@ -2404,7 +2404,8 @@ class AnnotatingParser {
       // not auto operator->() -> xxx;
       Current.setType(TT_TrailingReturnArrow);
     } else if (Current.is(tok::arrow) && Current.Previous &&
-               Current.Previous->is(tok::r_brace)) {
+               Current.Previous->is(tok::r_brace) &&
+               Current.Previous->is(BK_Block)) {
       // Concept implicit conversion constraint needs to be treated like
       // a trailing return type  ... } -> <type>.
       Current.setType(TT_TrailingReturnArrow);

clang/lib/Format/UnwrappedLineParser.cpp

@@ -570,8 +570,9 @@ void UnwrappedLineParser::calculateBraceTypes(bool ExpectClassBody) {
                                 NextTok->isOneOf(Keywords.kw_of, Keywords.kw_in,
                                                  Keywords.kw_as));
           ProbablyBracedList =
-              ProbablyBracedList || (IsCpp && (PrevTok->Tok.isLiteral() ||
-                                               NextTok->is(tok::l_paren)));
+              ProbablyBracedList ||
+              (IsCpp && (PrevTok->Tok.isLiteral() ||
+                         NextTok->isOneOf(tok::l_paren, tok::arrow)));
 
           // If there is a comma, semicolon or right paren after the closing
           // brace, we assume this is a braced initializer list.

clang/unittests/Format/TokenAnnotatorTest.cpp

@@ -2277,6 +2277,13 @@ TEST_F(TokenAnnotatorTest, UnderstandsTrailingReturnArrow) {
   ASSERT_EQ(Tokens.size(), 21u) << Tokens;
   EXPECT_TOKEN(Tokens[13], tok::arrow, TT_Unknown);
 
+  Tokens = annotate("Class<Type>{foo}->func(arg);");
+  ASSERT_EQ(Tokens.size(), 14u) << Tokens;
+  EXPECT_TOKEN(Tokens[4], tok::l_brace, TT_Unknown); // Not FunctionLBrace
+  EXPECT_BRACE_KIND(Tokens[4], BK_BracedInit);
+  EXPECT_BRACE_KIND(Tokens[6], BK_BracedInit);
+  EXPECT_TOKEN(Tokens[7], tok::arrow, TT_Unknown);
+
   auto Style = getLLVMStyle();
   Style.StatementAttributeLikeMacros.push_back("emit");
   Tokens = annotate("emit foo()->bar;", Style);