feat(parser): report errors on optional accessor properties

crates/oxc_parser/src/diagnostics.rs

@@ -249,6 +249,11 @@ pub fn constructor_async(span0: Span) -> OxcDiagnostic {
     OxcDiagnostic::error("Constructor can't be an async method").with_label(span0)
 }
 
+#[cold]
+pub fn optional_accessor_property(span: Span) -> OxcDiagnostic {
+    ts_error("1276", "An 'accessor' property cannot be declared optional.").with_label(span)
+}
+
 #[cold]
 pub fn identifier_async(x0: &str, span1: Span) -> OxcDiagnostic {
     OxcDiagnostic::error(format!("Cannot use `{x0}` as an identifier in an async context"))

crates/oxc_parser/src/js/class.rs

@@ -263,7 +263,13 @@ impl<'a> ParserImpl<'a> {
         let (key, computed) =
             if let Some(result) = key_name { result } else { self.parse_class_element_name()? };
 
-        let optional = self.eat(Kind::Question);
+        let (optional, optional_span) = if self.at(Kind::Question) {
+            let span = self.start_span();
+            self.bump_any();
+            (true, self.end_span(span))
+        } else {
+            (false, oxc_span::SPAN)
+        };
         let definite = self.eat(Kind::Bang);
 
         if let PropertyKey::PrivateIdentifier(private_ident) = &key {
@@ -281,6 +287,9 @@ impl<'a> ParserImpl<'a> {
         }
 
         if accessor {
+            if optional {
+                self.error(diagnostics::optional_accessor_property(optional_span));
+            }
             self.parse_class_accessor_property(span, key, computed, r#static, r#abstract).map(Some)
         } else if self.at(Kind::LParen) || self.at(Kind::LAngle) || r#async || generator {
             // LAngle for start of type parameters `foo<T>`

tasks/coverage/parser_babel.snap

@@ -10067,6 +10067,14 @@ Expect to Parse: tasks/coverage/babel/packages/babel-parser/test/fixtures/typesc
  4 │ 
    ╰────
 
+  × TS(1276): An 'accessor' property cannot be declared optional.
+   ╭─[babel/packages/babel-parser/test/fixtures/typescript/class/accessor-invalid/input.ts:7:14]
+ 6 │   abstract accessor #s;
+ 7 │   accessor #d?;
+   ·              ─
+ 8 │   abstract accessor f = 1;
+   ╰────
+
   × Expected a semicolon or an implicit semicolon after a statement, but found none
    ╭─[babel/packages/babel-parser/test/fixtures/typescript/class/declare-new-line-abstract/input.ts:1:8]
  1 │ declare abstract

tasks/coverage/parser_misc.snap

@@ -1,8 +1,7 @@
 parser_misc Summary:
 AST Parsed     : 27/27 (100.00%)
 Positive Passed: 27/27 (100.00%)
-Negative Passed: 15/16 (93.75%)
-Expect Syntax Error: tasks/coverage/misc/fail/oxc-5177.ts
+Negative Passed: 16/16 (100.00%)
 
   × Unexpected token
    ╭─[misc/fail/oxc-169.js:2:1]
@@ -231,6 +230,14 @@ Expect Syntax Error: tasks/coverage/misc/fail/oxc-5177.ts
  3 │ }
    ╰────
 
+  × TS(1276): An 'accessor' property cannot be declared optional.
+   ╭─[misc/fail/oxc-5177.ts:4:15]
+ 3 │ export class Bang {
+ 4 │     accessor x?: Foo
+   ·               ─
+ 5 │ }
+   ╰────
+
   × The keyword 'let' is reserved
    ╭─[misc/fail/oxc.js:1:1]
  1 │ let.a = 1;