release/21.x: [clang-format] Fix a regression in annotating star before lambda (llvm#170969)

Backport 4930e94

Author: owenca

clang/lib/Format/UnwrappedLineParser.cpp

@@ -2385,17 +2385,17 @@ bool UnwrappedLineParser::tryToParseLambdaIntroducer() {
   const FormatToken *LeftSquare = FormatTok;
   nextToken();
   if (Previous) {
+    const auto *PrevPrev = Previous->getPreviousNonComment();
+    if (Previous->is(tok::star) && PrevPrev && PrevPrev->isTypeName(LangOpts))
+      return false;
     if (Previous->closesScope()) {
       // Not a potential C-style cast.
       if (Previous->isNot(tok::r_paren))
         return false;
-      const auto *BeforeRParen = Previous->getPreviousNonComment();
       // Lambdas can be cast to function types only, e.g. `std::function<int()>`
       // and `int (*)()`.
-      if (!BeforeRParen || !BeforeRParen->isOneOf(tok::greater, tok::r_paren))
+      if (!PrevPrev || !PrevPrev->isOneOf(tok::greater, tok::r_paren))
         return false;
-    } else if (Previous->is(tok::star)) {
-      Previous = Previous->getPreviousNonComment();
     }
     if (Previous && Previous->Tok.getIdentifierInfo() &&
         !Previous->isOneOf(tok::kw_return, tok::kw_co_await, tok::kw_co_yield,

clang/unittests/Format/TokenAnnotatorTest.cpp

@@ -2248,6 +2248,12 @@ TEST_F(TokenAnnotatorTest, UnderstandsLambdas) {
   EXPECT_TOKEN(Tokens[3], tok::l_square, TT_LambdaLSquare);
   EXPECT_TOKEN(Tokens[5], tok::l_paren, TT_LambdaDefinitionLParen);
   EXPECT_TOKEN(Tokens[10], tok::l_square, TT_ArraySubscriptLSquare);
+
+  Tokens = annotate("foo = bar * [] { return 2; }();");
+  ASSERT_EQ(Tokens.size(), 15u) << Tokens;
+  EXPECT_TOKEN(Tokens[3], tok::star, TT_BinaryOperator);
+  EXPECT_TOKEN(Tokens[4], tok::l_square, TT_LambdaLSquare);
+  EXPECT_TOKEN(Tokens[6], tok::l_brace, TT_LambdaLBrace);
 }
 
 TEST_F(TokenAnnotatorTest, UnderstandsFunctionAnnotations) {