Merged: [parser] Fix AST func reindexing for function fields

AST reindexing has to skip visiting fields that are already in the
member initializer, as they will have already been visited when
visiting said initializer. This is the case for private fields and
fields with computed names.

However, the reindexer was incorrectly assuming that all properties
with a FunctionLiteral value are methods (and thus not fields, and
can safely be visited). This is not the case for fields with
function expression values.

Now, we correctly use the class property's "kind" when making this
visitation decision.

(cherry picked from commit a769ea7)

Bug: chromium:1132111
Tbr: leszeks@chromium.org
No-Try: true
No-Presubmit: true
No-Tree-Checks: true
Change-Id: I33ac5664bb5334e964d351de1ba7e2c57f3398f8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2465056
Commit-Queue: Adam Klein <adamk@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/branch-heads/8.6@{#24}
Cr-Branched-From: a64aed2-refs/heads/8.6.395@{#1}
Cr-Branched-From: a626bc0-refs/heads/master@{#69472}

src/ast/ast-function-literal-id-reindexer.cc

@@ -54,10 +54,10 @@ void AstFunctionLiteralIdReindexer::VisitClassLiteral(ClassLiteral* expr) {
     // Private fields have their key and value present in
     // instance_members_initializer_function, so they will
     // already have been visited.
-    if (prop->value()->IsFunctionLiteral()) {
-      Visit(prop->value());
-    } else {
+    if (prop->kind() == ClassLiteralProperty::Kind::FIELD) {
       CheckVisited(prop->value());
+    } else {
+      Visit(prop->value());
     }
   }
   ZonePtrList<ClassLiteral::Property>* props = expr->public_members();
@@ -67,7 +67,8 @@ void AstFunctionLiteralIdReindexer::VisitClassLiteral(ClassLiteral* expr) {
     // Public fields with computed names have their key
     // and value present in instance_members_initializer_function, so they will
     // already have been visited.
-    if (prop->is_computed_name() && !prop->value()->IsFunctionLiteral()) {
+    if (prop->is_computed_name() &&
+        prop->kind() == ClassLiteralProperty::Kind::FIELD) {
       if (!prop->key()->IsLiteral()) {
         CheckVisited(prop->key());
       }

test/mjsunit/regress/regress-1132111.js

@@ -0,0 +1,23 @@
+// Copyright 2020 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Public function field with computed name
+eval(`
+  buggy = ((bug = new class { [0] = x => 1337.0; }) => bug);
+`);
+
+// Public method with computed name
+eval(`
+  buggy = ((bug = new class { [0](x) { return 1337.0}; }) => bug);
+`);
+
+// Private function field with computed name
+eval(`
+  buggy = ((bug = new class { #foo = x => 1337.0; }) => bug);
+`);
+
+// Private method with computed name
+eval(`
+  buggy = ((bug = new class { #foo(x) { return 1337.0; } }) => bug);
+`);