fix(ts): raise error for export default interface {} (#13622)

packages/babel-parser/src/plugins/typescript/index.js

@@ -107,6 +107,8 @@ const TSErrors = makeErrorTemplates(
     InvalidModifiersOrder: "'%0' modifier must precede '%1' modifier.",
     InvalidTupleMemberLabel:
       "Tuple members must be labeled with a simple identifier.",
+    MissingInterfaceName:
+      "'interface' declarations must be followed by an identifier.",
     MixedLabeledAndUnlabeledElements:
       "Tuple members must all have names or all not have names.",
     NonAbstractClassHasAbstractMethod:
@@ -1419,12 +1421,18 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     tsParseInterfaceDeclaration(
       node: N.TsInterfaceDeclaration,
     ): N.TsInterfaceDeclaration {
-      node.id = this.parseIdentifier();
+      if (this.match(tt.name)) {
-      this.checkLVal(
+        node.id = this.parseIdentifier();
-        node.id,
+        this.checkLVal(
-        "typescript interface declaration",
+          node.id,
-        BIND_TS_INTERFACE,
+          "typescript interface declaration",
-      );
+          BIND_TS_INTERFACE,
+        );
+      } else {
+        node.id = null;
+        this.raise(this.state.start, TSErrors.MissingInterfaceName);
+      }
+
       node.typeParameters = this.tsTryParseTypeParameters();
       if (this.eat(tt._extends)) {
         node.extends = this.tsParseHeritageClause("extends");
@@ -2305,12 +2313,9 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       // export default interface allowed in:
       // https://github.com/Microsoft/TypeScript/pull/16040
       if (this.state.value === "interface") {
-        const result = this.tsParseDeclaration(
+        const interfaceNode = this.startNode();
-          this.startNode(),
+        this.next();
-          this.state.value,
+        const result = this.tsParseInterfaceDeclaration(interfaceNode);
-          true,
-        );
-
         if (result) return result;
       }
 

packages/babel-parser/src/types.js

@@ -1481,7 +1481,7 @@ export type TsImportType = TsTypeBase & {
 
 export type TsInterfaceDeclaration = DeclarationBase & {
   type: "TSInterfaceDeclaration",
-  id: Identifier,
+  id: ?Identifier,
   typeParameters: ?TsTypeParameterDeclaration,
   // TS uses "heritageClauses", but want this to resemble ClassBase.
   extends?: $ReadOnlyArray<TsExpressionWithTypeArguments>,

packages/babel-parser/test/fixtures/typescript/interface/export-default/input.ts

@@ -0,0 +1 @@
+export default interface {}

packages/babel-parser/test/fixtures/typescript/interface/export-default/output.json

@@ -0,0 +1,31 @@
+{
+  "type": "File",
+  "start":0,"end":27,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":27}},
+  "errors": [
+    "SyntaxError: 'interface' declarations must be followed by an identifier. (1:25)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":27,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":27}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportDefaultDeclaration",
+        "start":0,"end":27,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":27}},
+        "exportKind": "value",
+        "declaration": {
+          "type": "TSInterfaceDeclaration",
+          "start":15,"end":27,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":27}},
+          "id": null,
+          "body": {
+            "type": "TSInterfaceBody",
+            "start":25,"end":27,"loc":{"start":{"line":1,"column":25},"end":{"line":1,"column":27}},
+            "body": []
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}