fix(parser): reject incompatible class member modifiers (#22843)

`static`/`abstract` and `declare`/`override` are mutually exclusive in either
order (TS1243):

- `static abstract m()` / `abstract static m()`
- `declare override x` / `override declare x`

oxc already validated modifier order (TS1029) and duplicates (TS1030). This extends
the existing `ILLEGAL_PRECEDING_MODIFIERS` table in both directions for these pairs
and reports them as "cannot be used with" (TS1243) rather than "must precede" — the
fast path is unchanged (still a table lookup + AND); only the cold error path picks
the message.

Matches babel and TypeScript: parser_babel +1 negative-pass
(`class/modifiers-incompatible`), positive/AST stay 100% across all suites, and the
correct TS1243 diagnostic is now emitted on existing TypeScript cases.

crates/oxc_codegen/tests/integration/snapshots/minify.snap

@@ -96,13 +96,13 @@ class A {constructor(public readonly a: number) {}}
 ----------
 class A{constructor(public readonly a:number){}}
 ########## 22
-abstract class A {private abstract static m()}
+abstract class A {protected abstract m()}
 ----------
-abstract class A{private abstract static m();}
+abstract class A{protected abstract m();}
 ########## 23
-abstract class A {private abstract static readonly prop: string}
+class A {private static readonly prop: string}
 ----------
-abstract class A{private abstract static readonly prop:string}
+class A{private static readonly prop:string}
 ########## 24
 interface A { a: string, 'b': number, 'c'(): void }
 ----------

crates/oxc_codegen/tests/integration/snapshots/ts.snap

@@ -142,17 +142,17 @@ class A {
 }
 
 ########## 22
-abstract class A {private abstract static m()}
+abstract class A {protected abstract m()}
 ----------
 abstract class A {
-	private abstract static m();
+	protected abstract m();
 }
 
 ########## 23
-abstract class A {private abstract static readonly prop: string}
+class A {private static readonly prop: string}
 ----------
-abstract class A {
-	private abstract static readonly prop: string;
+class A {
+	private static readonly prop: string;
 }
 
 ########## 24

crates/oxc_codegen/tests/integration/ts.rs

@@ -89,8 +89,8 @@ fn ts() {
         "function <const T>(){}",
         "class A {m?(): void}",
         "class A {constructor(public readonly a: number) {}}",
-        "abstract class A {private abstract static m()}",
-        "abstract class A {private abstract static readonly prop: string}",
+        "abstract class A {protected abstract m()}",
+        "class A {private static readonly prop: string}",
         "interface A { a: string, 'b': number, 'c'(): void }",
         "enum A { a, 'b' }",
         "module 'a'",

crates/oxc_linter/src/rules/typescript/explicit_member_accessibility.rs

@@ -723,7 +723,7 @@ fn test() {
         (
             "
             abstract class Test {
-              private abstract accessor foo: number;
+              private accessor foo: number;
             }
                   ",
             None,

crates/oxc_linter/src/rules/typescript/explicit_module_boundary_types.rs

@@ -922,7 +922,7 @@ mod test {
                 return;
               }
               private arrow = one => 'arrow';
-              private abstract abs(one);
+              private abs(one) {}
             }
             ",
                 None,

crates/oxc_parser/src/diagnostics.rs

@@ -913,6 +913,28 @@ pub fn modifier_must_precede_other_modifier(
     .with_label(modifier.span())
 }
 
+#[cold]
+pub fn modifier_cannot_be_used_with_other_modifier(
+    span: Span,
+    modifier: ModifierKind,
+    other_modifier: ModifierKind,
+) -> OxcDiagnostic {
+    ts_error(
+        "1243",
+        format!("'{modifier}' modifier cannot be used with '{other_modifier}' modifier."),
+    )
+    .with_label(span)
+}
+
+#[cold]
+pub fn modifier_cannot_be_used_in_ambient_context(
+    span: Span,
+    modifier: ModifierKind,
+) -> OxcDiagnostic {
+    ts_error("1040", format!("'{modifier}' modifier cannot be used in an ambient context."))
+        .with_label(span)
+}
+
 #[cold]
 pub fn modifier_already_seen(modifier: &Modifier) -> OxcDiagnostic {
     ts_error("1030", format!("'{}' modifier already seen.", modifier.kind))

crates/oxc_parser/src/modifiers.rs

@@ -681,17 +681,21 @@ const fn get_illegal_preceding_modifiers(kind: ModifierKind) -> ModifierKinds {
             ModifierKind::Async,
             ModifierKind::Accessor,
             ModifierKind::Override,
+            ModifierKind::Abstract,
         ]),
         ModifierKind::Override => ModifierKinds::new([
             ModifierKind::Override,
             ModifierKind::Readonly,
             ModifierKind::Accessor,
             ModifierKind::Async,
+            ModifierKind::Declare,
         ]),
         ModifierKind::Abstract => ModifierKinds::new([
             ModifierKind::Abstract,
             ModifierKind::Override,
             ModifierKind::Accessor,
+            ModifierKind::Static,
+            ModifierKind::Private,
         ]),
         ModifierKind::Export => ModifierKinds::new([
             ModifierKind::Export,
@@ -699,6 +703,9 @@ const fn get_illegal_preceding_modifiers(kind: ModifierKind) -> ModifierKinds {
             ModifierKind::Abstract,
             ModifierKind::Async,
         ]),
+        ModifierKind::Declare => {
+            ModifierKinds::new([ModifierKind::Declare, ModifierKind::Override])
+        }
         _ => ModifierKinds::new([kind]),
     }
 }
@@ -731,6 +738,7 @@ impl<C: Config> ParserImpl<'_, C> {
             ModifierKind::Private,
             ModifierKind::Protected,
         ]);
+        use ModifierKind::{Abstract, Declare, Override, Private, Static};
 
         let this_kind = modifier.kind;
         let this_kinds = ModifierKinds::new([this_kind]);
@@ -757,7 +765,29 @@ impl<C: Config> ParserImpl<'_, C> {
         // If multiple illegal kinds, it's arbitrary which one the error is raised for.
         let illegal_kinds = illegal_preceding_modifier_kinds.intersection(existing_kinds);
         let illegal_kind = illegal_kinds.iter().next().unwrap();
-        self.error(diagnostics::modifier_must_precede_other_modifier(modifier, illegal_kind));
+        // Some pairs are mutually exclusive in either order. TypeScript reports them as TS1243
+        // ("cannot be used with") or TS1040 ("cannot be used in an ambient context") rather than
+        // as an ordering error (TS1029). Wording and codes follow `typescript-go`'s
+        // `checkGrammarModifiers`.
+        let span = modifier.span();
+        let error = match (this_kind, illegal_kind) {
+            (Static, Abstract) | (Abstract, Static) => {
+                diagnostics::modifier_cannot_be_used_with_other_modifier(span, Static, Abstract)
+            }
+            (Private, Abstract) | (Abstract, Private) => {
+                diagnostics::modifier_cannot_be_used_with_other_modifier(span, Private, Abstract)
+            }
+            // `declare override`
+            (Override, Declare) => {
+                diagnostics::modifier_cannot_be_used_with_other_modifier(span, Override, Declare)
+            }
+            // `override declare`
+            (Declare, Override) => {
+                diagnostics::modifier_cannot_be_used_in_ambient_context(span, Override)
+            }
+            _ => diagnostics::modifier_must_precede_other_modifier(modifier, illegal_kind),
+        };
+        self.error(error);
     }
 
     #[inline]

tasks/coverage/snapshots/parser_babel.snap

@@ -3,13 +3,11 @@ commit: d9fe348c
 parser_babel Summary:
 AST Parsed     : 2236/2236 (100.00%)
 Positive Passed: 2222/2236 (99.37%)
-Negative Passed: 1701/1723 (98.72%)
+Negative Passed: 1702/1723 (98.78%)
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/cast/unparenthesized-assert-and-assign/input.ts
 
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/cast/unparenthesized-type-assertion-and-assign/input.ts
 
-Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/class/modifiers-incompatible/input.ts
-
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/conditional/arrow-ambiguity/input.ts
 
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/conditional/arrow-like/input.ts
@@ -12902,6 +12900,38 @@ Expect to Parse: tasks/coverage/babel/packages/babel-parser/test/fixtures/typesc
  3 │   }
    ╰────
 
+  × TS(1243): 'static' modifier cannot be used with 'abstract' modifier.
+   ╭─[babel/packages/babel-parser/test/fixtures/typescript/class/modifiers-incompatible/input.ts:2:10]
+ 1 │ abstract class A extends Base {
+ 2 │   static abstract m1();
+   ·          ────────
+ 3 │   abstract static m1();
+   ╰────
+
+  × TS(1243): 'static' modifier cannot be used with 'abstract' modifier.
+   ╭─[babel/packages/babel-parser/test/fixtures/typescript/class/modifiers-incompatible/input.ts:3:12]
+ 2 │   static abstract m1();
+ 3 │   abstract static m1();
+   ·            ──────
+ 4 │ 
+   ╰────
+
+  × TS(1243): 'override' modifier cannot be used with 'declare' modifier.
+   ╭─[babel/packages/babel-parser/test/fixtures/typescript/class/modifiers-incompatible/input.ts:5:11]
+ 4 │ 
+ 5 │   declare override prop1: any;
+   ·           ────────
+ 6 │   override declare prop2: any;
+   ╰────
+
+  × TS(1040): 'override' modifier cannot be used in an ambient context.
+   ╭─[babel/packages/babel-parser/test/fixtures/typescript/class/modifiers-incompatible/input.ts:6:12]
+ 5 │   declare override prop1: any;
+ 6 │   override declare prop2: any;
+   ·            ───────
+ 7 │ }
+   ╰────
+
   × TS(1071): 'abstract' modifier cannot appear on an index signature.
    ╭─[babel/packages/babel-parser/test/fixtures/typescript/class/modifiers-index-signatures/input.ts:2:3]
  1 │ class C {
@@ -14499,6 +14529,14 @@ Expect to Parse: tasks/coverage/babel/packages/babel-parser/test/fixtures/typesc
  3 │ }
    ╰────
 
+  × TS(1243): 'static' modifier cannot be used with 'abstract' modifier.
+   ╭─[babel/packages/babel-parser/test/fixtures/typescript/static-blocks/invalid-static-block-with-modifier-abstract-02/input.ts:2:10]
+ 1 │ class Foo {
+ 2 │   static abstract {}
+   ·          ────────
+ 3 │ }
+   ╰────
+
   × Unexpected token
    ╭─[babel/packages/babel-parser/test/fixtures/typescript/static-blocks/invalid-static-block-with-modifier-abstract-02/input.ts:2:19]
  1 │ class Foo {

tasks/coverage/snapshots/parser_typescript.snap

@@ -3,7 +3,7 @@ commit: e5509e21
 parser_typescript Summary:
 AST Parsed     : 9779/9779 (100.00%)
 Positive Passed: 9779/9779 (100.00%)
-Negative Passed: 1591/2640 (60.27%)
+Negative Passed: 1592/2640 (60.30%)
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/FunctionDeclaration3.ts
 
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/FunctionDeclaration4.ts
@@ -1002,8 +1002,6 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/async/es6
 
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration3_es6.ts
 
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractProperties.ts
-
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/classes/classExpressions/classWithStaticFieldInParameterBindingPattern.2.ts
 
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/classes/classExpressions/classWithStaticFieldInParameterInitializer.2.ts
@@ -14558,6 +14556,14 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/types/wit
  3 │ }
    ╰────
 
+  × TS(1243): 'private' modifier cannot be used with 'abstract' modifier.
+   ╭─[typescript/tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMixedWithModifiers.ts:6:13]
+ 5 │     protected abstract foo_c();
+ 6 │     private abstract foo_d();
+   ·             ────────
+ 7 │ 
+   ╰────
+
   × TS(1029): 'public' modifier must precede 'abstract' modifier.
    ╭─[typescript/tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMixedWithModifiers.ts:8:14]
  7 │ 
@@ -14574,7 +14580,7 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/types/wit
  10 │     abstract private foo_dd();
     ╰────
 
-  × TS(1029): 'private' modifier must precede 'abstract' modifier.
+  × TS(1243): 'private' modifier cannot be used with 'abstract' modifier.
     ╭─[typescript/tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMixedWithModifiers.ts:10:14]
   9 │     abstract protected foo_cc();
  10 │     abstract private foo_dd();
@@ -14582,6 +14588,22 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/types/wit
  11 │ 
     ╰────
 
+  × TS(1243): 'static' modifier cannot be used with 'abstract' modifier.
+    ╭─[typescript/tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMixedWithModifiers.ts:12:14]
+ 11 │ 
+ 12 │     abstract static foo_d();
+    ·              ──────
+ 13 │     static abstract foo_e();
+    ╰────
+
+  × TS(1243): 'static' modifier cannot be used with 'abstract' modifier.
+    ╭─[typescript/tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMixedWithModifiers.ts:13:12]
+ 12 │     abstract static foo_d();
+ 13 │     static abstract foo_e();
+    ·            ────────
+ 14 │ 
+    ╰────
+
   × TS(2391): Function implementation is missing or not immediately following the declaration.
     ╭─[typescript/tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractOverloads.ts:15:5]
  14 │     
@@ -14590,6 +14612,22 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/types/wit
  16 │ }
     ╰────
 
+  × TS(1243): 'private' modifier cannot be used with 'abstract' modifier.
+   ╭─[typescript/tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractProperties.ts:5:13]
+ 4 │     protected abstract z : number;
+ 5 │     private abstract w : number;
+   ·             ────────
+ 6 │     
+   ╰────
+
+  × TS(1243): 'private' modifier cannot be used with 'abstract' modifier.
+    ╭─[typescript/tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractProperties.ts:12:13]
+ 11 │     protected abstract foo_z() : number;
+ 12 │     private abstract foo_w() : number;
+    ·             ────────
+ 13 │ }
+    ╰────
+
   × TS(1244): Abstract methods can only appear within an abstract class.
    ╭─[typescript/tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractUsingAbstractMethods2.ts:2:14]
  1 │ class A {
@@ -23839,6 +23877,14 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/types/wit
  7 │         super();
    ╰────
 
+  × TS(1040): 'override' modifier cannot be used in an ambient context.
+    ╭─[typescript/tests/cases/conformance/override/override5.ts:14:14]
+ 13 │ 
+ 14 │     override declare p2: number;
+    ·              ───────
+ 15 │ 
+    ╰────
+
   × TS(1029): 'override' modifier must precede 'readonly' modifier.
     ╭─[typescript/tests/cases/conformance/override/override5.ts:16:14]
  15 │ 
@@ -23880,6 +23926,14 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/types/wit
  45 │     abstract override b(): void;
     ╰────
 
+  × TS(1040): 'override' modifier cannot be used in an ambient context.
+    ╭─[typescript/tests/cases/conformance/override/override7.ts:11:14]
+ 10 │ 
+ 11 │     override declare p2: number;
+    ·              ───────
+ 12 │ 
+    ╰────
+
   × TS(1029): 'override' modifier must precede 'readonly' modifier.
     ╭─[typescript/tests/cases/conformance/override/override7.ts:13:14]
  12 │