[clang-format] Fix a bug in parsing C-style cast of lambdas (#136099)

Fix #135959

1 files changed, 18 insertions, 6 deletions

diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index b9430d4..df58e5e 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -2368,13 +2368,25 @@ bool UnwrappedLineParser::tryToParseLambdaIntroducer() {
   const FormatToken *Previous = FormatTok->Previous;
   const FormatToken *LeftSquare = FormatTok;
   nextToken();
-  if ((Previous && ((Previous->Tok.getIdentifierInfo() &&
-                     !Previous->isOneOf(tok::kw_return, tok::kw_co_await,
-                                        tok::kw_co_yield, tok::kw_co_return)) ||
-                    Previous->closesScope())) ||
-      LeftSquare->isCppStructuredBinding(IsCpp)) {
-    return false;
+  if (Previous) {
+    if (Previous->Tok.getIdentifierInfo() &&
+        !Previous->isOneOf(tok::kw_return, tok::kw_co_await, tok::kw_co_yield,
+                           tok::kw_co_return)) {
+      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))
+        return false;
+    }
   }
+  if (LeftSquare->isCppStructuredBinding(IsCpp))
+    return false;
   if (FormatTok->is(tok::l_square) || tok::isLiteral(FormatTok->Tok.getKind()))
     return false;
   if (FormatTok->is(tok::r_square)) {