Merged: Disallow tail calls from async functions and generators

src/parsing/parser.cc

Index: src/parsing/parser.cc
diff --git a/src/parsing/parser.cc b/src/parsing/parser.cc
index faadecd6a556ff50b1ef659ede0196954496e357..a39d0eec1284649fe8bc90f077550ed3c875e60a 100644
--- a/src/parsing/parser.cc
+++ b/src/parsing/parser.cc
@@ -2772,7 +2772,7 @@ Statement* Parser::ParseReturnStatement(bool* ok) {
           function_state_, ReturnExprContext::kInsideValidReturnStatement);
       return_value = ParseExpression(true, CHECK_OK);
 
-      if (allow_tailcalls() && !is_sloppy(language_mode())) {
+      if (allow_tailcalls() && !is_sloppy(language_mode()) && !is_resumable()) {
         // ES6 14.6.1 Static Semantics: IsInTailPosition
         function_state_->AddImplicitTailCallExpression(return_value);
       }