[class] Throw syntax error on deleting optional private property

Bug: v8:10564
Change-Id: Ibeaa43d9db087d02d8f4d3688fc1f6da41691a60
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2216931Reviewed-by: Shu-yu Guo <syg@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68373}

src/parsing/parser.h

@@ -541,10 +541,14 @@ class V8_EXPORT_PRIVATE Parser : public NON_EXPORTED_BASE(ParserBase<Parser>) {
     return property != nullptr && property->obj()->IsThisExpression();
   }
 
-  // Returns true if the expression is of type "obj.#foo".
+  // Returns true if the expression is of type "obj.#foo" or "obj?.#foo".
   V8_INLINE static bool IsPrivateReference(Expression* expression) {
     DCHECK_NOT_NULL(expression);
     Property* property = expression->AsProperty();
+    if (expression->IsOptionalChain()) {
+      Expression* expr_inner = expression->AsOptionalChain()->expression();
+      property = expr_inner->AsProperty();
+    }
     return property != nullptr && property->IsPrivateReference();
   }
 

src/parsing/preparser.h

@@ -575,6 +575,10 @@ class PreParserFactory {
   }
 
   PreParserExpression NewOptionalChain(const PreParserExpression& expr) {
+    // Needed to track `delete a?.#b` early errors
+    if (expr.IsPrivateReference()) {
+      return PreParserExpression::PrivateReference();
+    }
     return PreParserExpression::Default();
   }
 

test/cctest/test-parsing.cc

@@ -6225,10 +6225,22 @@ TEST(PrivateClassFieldsErrors) {
     "foo() { delete this.x.#a }",
     "foo() { delete this.x().#a }",
 
+    "foo() { delete this?.#a }",
+    "foo() { delete this.x?.#a }",
+    "foo() { delete this?.x.#a }",
+    "foo() { delete this.x()?.#a }",
+    "foo() { delete this?.x().#a }",
+
     "foo() { delete f.#a }",
     "foo() { delete f.x.#a }",
     "foo() { delete f.x().#a }",
 
+    "foo() { delete f?.#a }",
+    "foo() { delete f.x?.#a }",
+    "foo() { delete f?.x.#a }",
+    "foo() { delete f.x()?.#a }",
+    "foo() { delete f?.x().#a }",
+
     // ASI requires a linebreak
     "#a b",
     "#a = 0 b",