[class] Disallow return in class static blocks

Bug: v8:11719
Change-Id: Ib9064e09a77b03adc1234e2f1739983cdab24113
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2898778
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74619}

src/parsing/parser-base.h

@@ -5557,6 +5557,14 @@ typename ParserBase<Impl>::StatementT ParserBase<Impl>::ParseReturnStatement() {
     case MODULE_SCOPE:
       impl()->ReportMessageAt(loc, MessageTemplate::kIllegalReturn);
       return impl()->NullStatement();
+    case BLOCK_SCOPE:
+      // Class static blocks disallow return. They are their own var scopes and
+      // have a varblock scope.
+      if (function_state_->kind() == kClassStaticInitializerFunction) {
+        impl()->ReportMessageAt(loc, MessageTemplate::kIllegalReturn);
+        return impl()->NullStatement();
+      }
+      break;
     default:
       break;
   }

test/mjsunit/harmony/class-static-blocks.js

@@ -115,7 +115,15 @@
 
 {
   // 'await' is allowed as an identifier name in named function expressions.
-  class C { static { (function await() {}); } }
+  class C1 { static { (function await() {}); } }
+  // 'return' is allowed across function boundaries inside static blocks.
+  class C2 { static {
+      function f1() { return; }
+      function f2() { return 0; }
+      let f3 = (x => { return x; })
+      let f4 = (x => { return; })
+    }
+  }
 }
 
 function assertDoesntParse(expr, context_start, context_end) {
@@ -142,4 +150,8 @@ for (let [s, e] of [['', ''],
   assertDoesntParse('try {} catch ({await}) {}', s, e);
   assertDoesntParse('var {await} = 0;', s, e);
   assertDoesntParse('({await} = 0);', s, e);
+  assertDoesntParse('return;', s, e);
+  assertDoesntParse('return 0;', s, e);
+  assertDoesntParse('{ return; }', s, e);
+  assertDoesntParse('{ return 0; }', s, e);
 }