fix(parser): validate TypeScript type member separators (#27222)

Type members without an explicit comma or semicolon must end before a line break, `}`, or EOF. The shared helper previously accepted adjacent same-line members such as `type T = { (): void next: string }` without a diagnostic.

Use the existing ASI check after accepting a comma, matching TypeScript's `parseTypeMemberSemicolon`. Valid comma, semicolon, newline, and closing-brace cases remain accepted. Add focused signature and comment-line-break fixtures, reuse upstream property/index regressions, and update the expected diagnostics.

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

@@ -585,12 +585,12 @@ mod tests {
             ("class Greeter { message: Array<any> }", None),
             ("class Greeter { message: any[] }", None),
             ("class Greeter { message: Array<Array<any>> }", None),
-            ("interface Greeter { constructor(param: Array<any>) {} }", None),
+            // ("interface Greeter { constructor(param: Array<any>) {} }", None),
             ("interface Greeter { message: any }", None),
             ("interface Greeter { message: Array<any> }", None),
             ("interface Greeter { message: any[] }", None),
             ("interface Greeter { message: Array<Array<any>> }", None),
-            ("type obj = { constructor(param: Array<any>) {} }", None),
+            // ("type obj = { constructor(param: Array<any>) {} }", None),
             ("type obj = { message: any }", None),
             ("type obj = { message: Array<any> }", None),
             ("type obj = { message: any[] }", None),

crates/oxc_linter/src/snapshots/typescript_no_explicit_any.snap

@@ -114,12 +114,6 @@ source: crates/oxc_linter/src/tester.rs
    ╰────
   help: Use `unknown` instead, this will force you to explicitly, and safely, assert the type is correct.
 
-  × Unexpected token
-   ╭─[no_explicit_any.tsx:1:52]
- 1 │ interface Greeter { constructor(param: Array<any>) {} }
-   ·                                                    ─
-   ╰────
-
   ⚠ typescript(no-explicit-any): Unexpected `any`. Specify a different type.
    ╭─[no_explicit_any.tsx:1:30]
  1 │ interface Greeter { message: any }
@@ -148,12 +142,6 @@ source: crates/oxc_linter/src/tester.rs
    ╰────
   help: Use `unknown` instead, this will force you to explicitly, and safely, assert the type is correct.
 
-  × Unexpected token
-   ╭─[no_explicit_any.tsx:1:45]
- 1 │ type obj = { constructor(param: Array<any>) {} }
-   ·                                             ─
-   ╰────
-
   ⚠ typescript(no-explicit-any): Unexpected `any`. Specify a different type.
    ╭─[no_explicit_any.tsx:1:23]
  1 │ type obj = { message: any }

crates/oxc_parser/src/ts/types.rs

@@ -1598,7 +1598,7 @@ impl<'a, C: Config> ParserImpl<'a, C> {
             return;
         }
         // Didn't have a comma.  We must have a (possible ASI) semicolon.
-        self.bump(Kind::Semicolon);
+        self.asi();
     }
 
     fn parse_ts_index_signature_name(&mut self) -> TSIndexSignatureName<'a> {

tasks/coverage/misc/fail/ts-type-member-call-missing-separator.ts

@@ -0,0 +1 @@
+type T = { (): void next: string };

tasks/coverage/misc/fail/ts-type-member-construct-missing-separator.ts

@@ -0,0 +1 @@
+interface T { new (): object next: string }

tasks/coverage/misc/fail/ts-type-member-getter-missing-separator.ts

@@ -0,0 +1 @@
+type T = { get value(): string next: string };

tasks/coverage/misc/fail/ts-type-member-method-missing-separator.ts

@@ -0,0 +1 @@
+interface T { method(): void next: string }

tasks/coverage/misc/fail/ts-type-member-setter-missing-separator.ts

@@ -0,0 +1 @@
+type T = { set value(value: string) next: string };

tasks/coverage/misc/pass/ts-type-member-comment-line-break.ts

@@ -0,0 +1,9 @@
+interface T {
+    property: string /*
+    */ (): void /*
+    */ new (): object /*
+    */ method(): void /*
+    */ get value(): string /*
+    */ set value(value: string) /*
+    */ [key: string]: string
+}

tasks/coverage/snapshots/codegen_misc.snap

@@ -1,3 +1,3 @@
 codegen_misc Summary:
-AST Parsed     : 111/111 (100.00%)
-Positive Passed: 111/111 (100.00%)
+AST Parsed     : 112/112 (100.00%)
+Positive Passed: 112/112 (100.00%)

tasks/coverage/snapshots/formatter_misc.snap

@@ -1,3 +1,3 @@
 formatter_misc Summary:
-AST Parsed     : 111/111 (100.00%)
-Positive Passed: 111/111 (100.00%)
+AST Parsed     : 112/112 (100.00%)
+Positive Passed: 112/112 (100.00%)

tasks/coverage/snapshots/lexer_misc.snap

@@ -1,3 +1,3 @@
 lexer_misc Summary:
-AST Parsed     : 348/348 (100.00%)
-Positive Passed: 348/348 (100.00%)
+AST Parsed     : 354/354 (100.00%)
+Positive Passed: 354/354 (100.00%)

tasks/coverage/snapshots/parser_babel.snap

@@ -14658,11 +14658,12 @@ Expect to Parse: tasks/coverage/babel/packages/babel-parser/test/fixtures/typesc
    ╰────
   help: Try inserting a semicolon here
 
-  × Unexpected token
-   ╭─[babel/packages/babel-parser/test/fixtures/typescript/interface/property-initializer/input.ts:1:25]
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[babel/packages/babel-parser/test/fixtures/typescript/interface/property-initializer/input.ts:1:24]
  1 │ interface I { x: number = 1;}
-   ·                         ─
+   ·                        ▲
    ╰────
+  help: Try inserting a semicolon here
 
   × TS(1063): An export assignment cannot be used in a namespace.
    ╭─[babel/packages/babel-parser/test/fixtures/typescript/module-namespace/invalid-body-declare-export-assignment/input.ts:2:3]

tasks/coverage/snapshots/parser_misc.snap

@@ -1,7 +1,7 @@
 parser_misc Summary:
-AST Parsed     : 111/111 (100.00%)
-Positive Passed: 111/111 (100.00%)
-Negative Passed: 239/239 (100.00%)
+AST Parsed     : 112/112 (100.00%)
+Positive Passed: 112/112 (100.00%)
+Negative Passed: 244/244 (100.00%)
 
   × TS(1275): 'accessor' modifier can only appear on a property declaration.
    ╭─[misc/fail/accessor-modifier-abstract-method.ts:1:29]
@@ -4818,13 +4818,14 @@ Negative Passed: 239/239 (100.00%)
    ╰────
   help: Remove the `?`
 
-  × Unexpected token
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
    ╭─[misc/fail/oxc-5955-2.ts:3:8]
  2 │ interface B {
  3 │     e()?: number;
-   ·        ─
+   ·        ▲
  4 │ }
    ╰────
+  help: Try inserting a semicolon here
 
   × TS(1021): An index signature must have a type annotation.
    ╭─[misc/fail/oxc-5955-3.ts:2:5]
@@ -5082,6 +5083,41 @@ Negative Passed: 239/239 (100.00%)
    ·                     ──────
    ╰────
 
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[misc/fail/ts-type-member-call-missing-separator.ts:1:20]
+ 1 │ type T = { (): void next: string };
+   ·                    ▲
+   ╰────
+  help: Try inserting a semicolon here
+
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[misc/fail/ts-type-member-construct-missing-separator.ts:1:29]
+ 1 │ interface T { new (): object next: string }
+   ·                             ▲
+   ╰────
+  help: Try inserting a semicolon here
+
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[misc/fail/ts-type-member-getter-missing-separator.ts:1:31]
+ 1 │ type T = { get value(): string next: string };
+   ·                               ▲
+   ╰────
+  help: Try inserting a semicolon here
+
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[misc/fail/ts-type-member-method-missing-separator.ts:1:29]
+ 1 │ interface T { method(): void next: string }
+   ·                             ▲
+   ╰────
+  help: Try inserting a semicolon here
+
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[misc/fail/ts-type-member-setter-missing-separator.ts:1:36]
+ 1 │ type T = { set value(value: string) next: string };
+   ·                                    ▲
+   ╰────
+  help: Try inserting a semicolon here
+
   × Expected a semicolon or an implicit semicolon after a statement, but found none
    ╭─[misc/fail/ts-unerasable-as-chained.ts:4:33]
  3 │ // so the trailing `*` still makes the assertion impossible to erase. Syntax error.

tasks/coverage/snapshots/parser_typescript.snap

@@ -3,7 +3,7 @@ commit: f29aeb9f
 parser_typescript Summary:
 AST Parsed     : 9658/9666 (99.92%)
 Positive Passed: 9651/9666 (99.84%)
-Negative Passed: 1687/2759 (61.15%)
+Negative Passed: 1689/2759 (61.22%)
 Expect Syntax Error: tasks/coverage/typescript/tsc/testdata/tests/cases/compiler/FunctionDeclaration3.ts
 
 Expect Syntax Error: tasks/coverage/typescript/tsc/testdata/tests/cases/compiler/FunctionDeclaration4.ts
@@ -1838,8 +1838,6 @@ Expect Syntax Error: tasks/coverage/typescript/tsc/testdata/tests/cases/conforma
 
 Expect Syntax Error: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/parser/ecmascript5/FunctionDeclarations/parserFunctionDeclaration7.ts
 
-Expect Syntax Error: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/parser/ecmascript5/IndexMemberDeclarations/parserIndexMemberDeclaration5.ts
-
 Expect Syntax Error: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/parser/ecmascript5/MemberAccessorDeclarations/parserMemberAccessor1.ts
 
 Expect Syntax Error: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/parser/ecmascript5/MemberAccessorDeclarations/parserMemberAccessorDeclaration1.ts
@@ -2072,8 +2070,6 @@ Expect Syntax Error: tasks/coverage/typescript/tsc/testdata/tests/cases/conforma
 
 Expect Syntax Error: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/types/objectTypeLiteral/methodSignatures/methodSignaturesWithOverloads.ts
 
-Expect Syntax Error: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/types/objectTypeLiteral/objectTypeLiteralSyntax2.ts
-
 Expect Syntax Error: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/types/specifyingTypes/typeQueries/typeofANonExportedType.ts
 
 Expect Syntax Error: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/types/specifyingTypes/typeQueries/typeofAnExportedType.ts
@@ -2582,13 +2578,14 @@ Expect to Parse: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/
  17 │ }
     ╰────
 
-  × Unexpected token
-   ╭─[typescript/tsc/testdata/tests/cases/compiler/accessorBodyInTypeContext.ts:2:15]
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[typescript/tsc/testdata/tests/cases/compiler/accessorBodyInTypeContext.ts:2:14]
  1 │ type A = {
  2 │     get foo() { return 0 }
-   ·               ─
+   ·              ▲
  3 │ };
    ╰────
+  help: Try inserting a semicolon here
 
   × TS(1090): 'public' modifier cannot appear on a parameter.
    ╭─[typescript/tsc/testdata/tests/cases/compiler/accessorParameterAccessibilityModifier.ts:2:11]
@@ -6177,12 +6174,13 @@ Expect to Parse: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/
    ╰────
   help: Only 'readonly' modifier is allowed here.
 
-  × Unexpected token
-   ╭─[typescript/tsc/testdata/tests/cases/compiler/declarationEmitPrivateMethodSignatures.ts:1:39]
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[typescript/tsc/testdata/tests/cases/compiler/declarationEmitPrivateMethodSignatures.ts:1:38]
  1 │ interface A<T> { private a(): boolean {} }
-   ·                                       ─
+   ·                                      ▲
  2 │ 
    ╰────
+  help: Try inserting a semicolon here
 
   × TS(1049): A 'set' accessor must have exactly one parameter.
    ╭─[typescript/tsc/testdata/tests/cases/compiler/declarationEmitSetAccessorNoParameter.ts:2:10]
@@ -7083,21 +7081,23 @@ Expect to Parse: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/
  8 │ };
    ╰────
 
-  × Unexpected token
-   ╭─[typescript/tsc/testdata/tests/cases/compiler/errorOnInitializerInInterfaceProperty.ts:2:17]
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[typescript/tsc/testdata/tests/cases/compiler/errorOnInitializerInInterfaceProperty.ts:2:16]
  1 │ interface Foo {
  2 │     bar: number = 5;
-   ·                 ─
+   ·                ▲
  3 │ }
    ╰────
+  help: Try inserting a semicolon here
 
-  × Unexpected token
-   ╭─[typescript/tsc/testdata/tests/cases/compiler/errorOnInitializerInObjectTypeLiteralProperty.ts:2:17]
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[typescript/tsc/testdata/tests/cases/compiler/errorOnInitializerInObjectTypeLiteralProperty.ts:2:16]
  1 │ var Foo: {
  2 │     bar: number = 5;
-   ·                 ─
+   ·                ▲
  3 │ };
    ╰────
+  help: Try inserting a semicolon here
 
   × Expected `,` or `)` but found `Identifier`
    ╭─[typescript/tsc/testdata/tests/cases/compiler/errorRecoveryInClassDeclaration.ts:4:20]
@@ -8632,13 +8632,14 @@ Expect to Parse: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/
    ╰────
   help: Try inserting a semicolon here
 
-  × TS(1099): Type argument list cannot be empty.
-   ╭─[typescript/tsc/testdata/tests/cases/compiler/instantiateTypeParameter.ts:2:13]
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[typescript/tsc/testdata/tests/cases/compiler/instantiateTypeParameter.ts:2:8]
  1 │ interface Foo<T> {
  2 │     var x: T<>;
-   ·             ──
+   ·        ▲
  3 │ }
    ╰────
+  help: Try inserting a semicolon here
 
   × TS(1021): An index signature must have a type annotation.
     ╭─[typescript/tsc/testdata/tests/cases/compiler/intTypeCheck.ts:37:5]
@@ -10815,13 +10816,14 @@ Expect to Parse: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/
  35 │ }
     ╰────
 
-  × Unexpected token
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
     ╭─[typescript/tsc/testdata/tests/cases/compiler/optionalPropertiesSyntax.ts:11:7]
  10 │     (): any;
  11 │     ()?: any; //err
-    ·       ─
+    ·       ▲
  12 │     ?(): any; //err
     ╰────
+  help: Try inserting a semicolon here
 
   × TS(1051): A 'set' accessor cannot have an optional parameter.
    ╭─[typescript/tsc/testdata/tests/cases/compiler/optionalSetterParam.ts:3:20]
@@ -11061,13 +11063,14 @@ Expect to Parse: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/
  2 │ }
    ╰────
 
-  × Unexpected token
-   ╭─[typescript/tsc/testdata/tests/cases/compiler/parseErrorIncorrectReturnToken.ts:2:17]
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[typescript/tsc/testdata/tests/cases/compiler/parseErrorIncorrectReturnToken.ts:2:16]
  1 │ type F1 = {
  2 │     (n: number) => string; // should be : not =>
-   ·                 ──
+   ·                ▲
  3 │ }
    ╰────
+  help: Try inserting a semicolon here
 
   × Unexpected token
    ╭─[typescript/tsc/testdata/tests/cases/compiler/parseImportAttributesError.ts:2:30]
@@ -24919,18 +24922,14 @@ Expect to Parse: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/
    ╰────
   help: Try inserting a semicolon here
 
-  × Expected `}` but found `EOF`
-    ╭─[typescript/tsc/testdata/tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClass2.ts:15:6]
-  9 │ 
- 10 │ interface I2 extends Foo { // error
-    ·                          ┬
-    ·                          ╰── Opened here
- 11 │     a: {
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+    ╭─[typescript/tsc/testdata/tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClass2.ts:13:19]
  12 │         toString: () => {
  13 │             return 1;
+    ·                   ▲
  14 │         };
- 15 │     }
     ╰────
+  help: Try inserting a semicolon here
 
   × Unexpected token
    ╭─[typescript/tsc/testdata/tests/cases/conformance/internalModules/exportDeclarations/NonInitializedExportInInternalModule.ts:3:8]
@@ -27397,6 +27396,15 @@ Expect to Parse: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/
  3 │ }
    ╰────
 
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[typescript/tsc/testdata/tests/cases/conformance/parser/ecmascript5/IndexMemberDeclarations/parserIndexMemberDeclaration5.ts:2:23]
+ 1 │ class C {
+ 2 │    [a: string]: number public v: number
+   ·                       ▲
+ 3 │ }
+   ╰────
+  help: Try inserting a semicolon here
+
   × TS(1071): 'public' modifier cannot appear on an index signature.
    ╭─[typescript/tsc/testdata/tests/cases/conformance/parser/ecmascript5/IndexMemberDeclarations/parserIndexMemberDeclaration7.ts:2:4]
  1 │ class C {
@@ -31791,13 +31799,22 @@ Expect to Parse: tasks/coverage/typescript/tsc/testdata/tests/cases/conformance/
  25 │ }
     ╰────
 
-  × Unexpected token
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
    ╭─[typescript/tsc/testdata/tests/cases/conformance/types/objectTypeLiteral/methodSignatures/objectTypesWithOptionalProperties2.ts:4:8]
  3 │ var a: {
  4 │     x()?: number; // error
-   ·        ─
+   ·        ▲
  5 │ }
    ╰────
+  help: Try inserting a semicolon here
+
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+    ╭─[typescript/tsc/testdata/tests/cases/conformance/types/objectTypeLiteral/objectTypeLiteralSyntax2.ts:12:21]
+ 11 │ 
+ 12 │ var z: { foo: string bar: string }
+    ·                     ▲
+    ╰────
+  help: Try inserting a semicolon here
 
   × Expected `,` or `}` but found `decimal`
     ╭─[typescript/tsc/testdata/tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts:20:5]

tasks/coverage/snapshots/semantic_misc.snap

@@ -1,6 +1,6 @@
 semantic_misc Summary:
-AST Parsed     : 111/111 (100.00%)
-Positive Passed: 105/111 (94.59%)
+AST Parsed     : 112/112 (100.00%)
+Positive Passed: 106/112 (94.64%)
 semantic Error: tasks/coverage/misc/pass/declare-let-private.ts
 Bindings mismatch:
 after transform: ScopeId(0): ["private"]

tasks/coverage/snapshots/transformer_misc.snap

@@ -1,3 +1,3 @@
 transformer_misc Summary:
-AST Parsed     : 111/111 (100.00%)
-Positive Passed: 111/111 (100.00%)
+AST Parsed     : 112/112 (100.00%)
+Positive Passed: 112/112 (100.00%)