Support trailing commas in typeof import()

Author: nicolo-ribaudo

playground/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "playground",
+  "version": "1.0.0",
+  "main": "test.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "description": "",
+  "dependencies": {
+    "typescript": "file:.."
+  }
+}

playground/src/test.js

@@ -0,0 +1,13 @@
+// Enum without initializers have first member = 0 and successive members = N + 1
+// Enum literal syntax does not implement auto-incrementing behaviour.
+let ExistingShorthand = "exists";
+const E1 = {
+    Int: 1// Enum without initializers have first member = 0 and successive members = N + 1
+    // Enum literal syntax does not implement auto-incrementing behaviour.
+    , // Enum without initializers have first member = 0 and successive members = N + 1
+    String: "string"// Enum without initializers have first member = 0 and successive members = N + 1
+    // Enum literal syntax does not implement auto-incrementing behaviour.
+    , // Enum without initializers have first member = 0 and successive members = N + 1
+    Flag: 8// Enum without initializers have first member = 0 and successive members = N + 1
+    // Enum literal syntax does not implement auto-incrementing behaviour.
+};

playground/src/test.ts

@@ -0,0 +1,9 @@
+// Enum without initializers have first member = 0 and successive members = N + 1
+
+// Enum literal syntax does not implement auto-incrementing behaviour.
+let ExistingShorthand = "exists";
+const E1: enum = {
+    Int: 1, // ok
+    String: "string", // ok
+    Flag: 8, // ok
+};

playground/tsconfig.json

@@ -0,0 +1,8 @@
+{
+  "compilerOptions": {
+    "target": "ESNext",
+    "module": "ESNext",
+    "skipLibCheck": true,
+  },
+  "include": ["./src/**/*"]
+}

src/compiler/parser.ts

@@ -4551,7 +4551,7 @@ namespace Parser {
         parseExpected(SyntaxKind.OpenParenToken);
         const type = parseType();
         let attributes: ImportAttributes | undefined;
-        if (parseOptional(SyntaxKind.CommaToken)) {
+        if (parseOptional(SyntaxKind.CommaToken) && token() !== SyntaxKind.CloseParenToken) {
             const openBracePosition = scanner.getTokenStart();
             parseExpected(SyntaxKind.OpenBraceToken);
             const currentToken = token();
@@ -4572,6 +4572,7 @@ namespace Parser {
                     );
                 }
             }
+            parseOptional(SyntaxKind.CommaToken);
         }
         parseExpected(SyntaxKind.CloseParenToken);
         const qualifier = parseOptional(SyntaxKind.DotToken) ? parseEntityNameOfTypeReference() : undefined;

tests/baselines/reference/typeofImportInvalidElision.errors.txt

@@ -0,0 +1,12 @@
+main.ts(1,39): error TS1005: '{' expected.
+
+
+==== input.ts (0 errors) ====
+    export type X = 1;
+    
+==== main.ts (1 errors) ====
+    type T2 = typeof import('./input.js', ,);
+                                          ~
+!!! error TS1005: '{' expected.
+!!! related TS1007 main.ts:1:39: The parser expected to find a '}' to match the '{' token here.
+    

tests/baselines/reference/typeofImportInvalidElision.js

@@ -0,0 +1,13 @@
+//// [tests/cases/compiler/typeofImportInvalidElision.ts] ////
+
+//// [input.ts]
+export type X = 1;
+
+//// [main.ts]
+type T2 = typeof import('./input.js', ,);
+
+
+//// [input.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+//// [main.js]

tests/baselines/reference/typeofImportInvalidElision.symbols

@@ -0,0 +1,10 @@
+//// [tests/cases/compiler/typeofImportInvalidElision.ts] ////
+
+=== input.ts ===
+export type X = 1;
+>X : Symbol(X, Decl(input.ts, 0, 0))
+
+=== main.ts ===
+type T2 = typeof import('./input.js', ,);
+>T2 : Symbol(T2, Decl(main.ts, 0, 0))
+

tests/baselines/reference/typeofImportInvalidElision.types

@@ -0,0 +1,12 @@
+//// [tests/cases/compiler/typeofImportInvalidElision.ts] ////
+
+=== input.ts ===
+export type X = 1;
+>X : 1
+>  : ^
+
+=== main.ts ===
+type T2 = typeof import('./input.js', ,);
+>T2 : typeof import("input")
+>   : ^^^^^^^^^^^^^^^^^^^^^^
+

tests/baselines/reference/typeofImportTrailingCommas.js

@@ -0,0 +1,14 @@
+//// [tests/cases/compiler/typeofImportTrailingCommas.ts] ////
+
+//// [input.ts]
+export type X = 1;
+
+//// [main.ts]
+type T1 = typeof import('./input.js',)
+type T2 = typeof import('./input.js', { with: { "resolution-mode": "import" } },);
+
+
+//// [input.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+//// [main.js]