feat(parser): report class properties that are both definite and opti…

…onal (#5181)

crates/oxc_parser/src/diagnostics.rs

@@ -254,6 +254,14 @@ pub fn optional_accessor_property(span: Span) -> OxcDiagnostic {
     ts_error("1276", "An 'accessor' property cannot be declared optional.").with_label(span)
 }
 
+#[cold]
+pub fn optional_definite_property(span: Span) -> OxcDiagnostic {
+    // NOTE: could not find an error code when tsc parses this; its parser panics.
+    OxcDiagnostic::error("A property cannot be both optional and definite.")
+        .with_label(span)
+        .with_help("Remove either the `?` or the `!`")
+}
+
 #[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

@@ -272,6 +272,10 @@ impl<'a> ParserImpl<'a> {
         };
         let definite = self.eat(Kind::Bang);
 
+        if optional && definite {
+            self.error(diagnostics::optional_definite_property(optional_span.expand_right(1)));
+        }
+
         if let PropertyKey::PrivateIdentifier(private_ident) = &key {
             // `private #foo`, etc. is illegal
             if self.ts_enabled() {

tasks/coverage/parser_babel.snap

@@ -3,7 +3,7 @@ commit: 12619ffe
 parser_babel Summary:
 AST Parsed     : 2092/2100 (99.62%)
 Positive Passed: 2082/2100 (99.14%)
-Negative Passed: 1379/1492 (92.43%)
+Negative Passed: 1380/1492 (92.49%)
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/annex-b/enabled/3.1-sloppy-labeled-functions-if-body/input.js
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/core/categorized/invalid-fn-decl-labeled-inside-if/input.js
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/core/categorized/invalid-fn-decl-labeled-inside-loop/input.js
@@ -53,7 +53,6 @@ Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/ty
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/class/modifiers-override-errors/input.ts
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/class/parameter-properties-binding-patterns/input.ts
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/class/private-fields-modifier-abstract/input.ts
-Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/class/property-optional-definite-assignment-not-allowed/input.ts
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/declare/function/input.ts
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/declare/module-class/input.ts
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/declare/module-function/input.ts
@@ -10264,6 +10263,15 @@ Expect to Parse: tasks/coverage/babel/packages/babel-parser/test/fixtures/typesc
  3 │ }
    ╰────
 
+  × A property cannot be both optional and definite.
+   ╭─[babel/packages/babel-parser/test/fixtures/typescript/class/property-optional-definite-assignment-not-allowed/input.ts:2:4]
+ 1 │ class C {
+ 2 │   x?!: number;
+   ·    ──
+ 3 │ }
+   ╰────
+  help: Remove either the `?` or the `!`
+
   × Unexpected token
    ╭─[babel/packages/babel-parser/test/fixtures/typescript/const/invalid-initializer-ambient-context/input.ts:2:35]
  1 │ declare module N {