Always immediately propagate flags outwards rather than relying on PropagateScopeInfo

src/parsing/parser-base.h

Index: src/parsing/parser-base.h
diff --git a/src/parsing/parser-base.h b/src/parsing/parser-base.h
index e629ef2cbe588b80dbbdbdd10d7b31ff634ed8d5..a5ebacb63fdd68d8bd4419f8954a4b74ad5c8076 100644
--- a/src/parsing/parser-base.h
+++ b/src/parsing/parser-base.h
@@ -3460,8 +3460,9 @@ ParserBase<Traits>::ParseArrowFunctionLiteral(
     if (peek() == Token::LBRACE) {
       // Multiple statement body
       Consume(Token::LBRACE);
-      bool is_lazily_parsed =
-          (mode() == PARSE_LAZILY && scope()->AllowsLazyParsing());
+      DCHECK_EQ(scope(), formal_parameters.scope);
+      bool is_lazily_parsed = (mode() == PARSE_LAZILY &&
+                               formal_parameters.scope->AllowsLazyParsing());
       if (is_lazily_parsed) {
         body = this->NewStatementList(0, zone());
         this->SkipLazyFunctionBody(&materialized_literal_count,