Allow constructor and method signatures in classes

src/parsing/preparser.cc

Index: src/parsing/preparser.cc
diff --git a/src/parsing/preparser.cc b/src/parsing/preparser.cc
index 2be6301db258e2bcd8c84316c09ed4187a09dd25..cf54051d94053e24afb122045f14d30fbe52a0f6 100644
--- a/src/parsing/preparser.cc
+++ b/src/parsing/preparser.cc
@@ -1059,7 +1059,9 @@ PreParser::Expression PreParser::ParseFunctionLiteral(
   parenthesized_function_ = false;
 
   // Parse optional type annotation.
-  if (scope_->typed() && Check(Token::COLON)) {  // Braces required here.
+  if (scope_->typed() &&
+      !(type_flags & typesystem::kDisallowTypeAnnotation) &&
+      Check(Token::COLON)) {  // Braces required here.
     ParseValidType(CHECK_OK);
   }