babel · nicolo-ribaudo · Feb 9, 2023 · Feb 8, 2023 · Feb 8, 2023 · Feb 9, 2023
diff --git a/packages/babel-parser/src/parser/lval.ts b/packages/babel-parser/src/parser/lval.ts
@@ -366,7 +366,7 @@ export default abstract class LValParser extends NodeUtils {
         node.elements = this.parseBindingList(
           tt.bracketR,
           charCodes.rightSquareBracket,
-          true,
+          { allowEmpty: true },
         );
         return this.finishNode(node, "ArrayPattern");
       }
@@ -384,8 +384,15 @@ export default abstract class LValParser extends NodeUtils {
     this: Parser,
     close: TokenType,
     closeCharCode: typeof charCodes[keyof typeof charCodes],
-    allowEmpty?: boolean,
-    allowModifiers?: boolean,
+    {
+      allowEmpty = false,
+      allowModifiers = false,
+      isFunctionParams = false,
+    }: {
+      allowEmpty?: boolean;
+      allowModifiers?: boolean;
+      isFunctionParams?: boolean;
+    } = {},
   ): Array<Pattern | TSParameterProperty> {
     const elts: Array<Pattern | TSParameterProperty> = [];
     let first = true;
@@ -400,7 +407,12 @@ export default abstract class LValParser extends NodeUtils {
       } else if (this.eat(close)) {
         break;
       } else if (this.match(tt.ellipsis)) {
-        elts.push(this.parseAssignableListItemTypes(this.parseRestBinding()));
+        elts.push(
+          this.parseAssignableListItemTypes(
+            this.parseRestBinding(),
+            isFunctionParams,
+          ),
+        );
         if (!this.checkCommaAfterRest(closeCharCode)) {
           this.expect(close);
           break;
@@ -416,7 +428,13 @@ export default abstract class LValParser extends NodeUtils {
         while (this.match(tt.at)) {
           decorators.push(this.parseDecorator());
         }
-        elts.push(this.parseAssignableListItem(allowModifiers, decorators));
+        elts.push(
+          this.parseAssignableListItem(
+            allowModifiers,
+            decorators,
+            isFunctionParams,
+          ),
+        );
       }
     }
     return elts;
@@ -462,9 +480,10 @@ export default abstract class LValParser extends NodeUtils {
     this: Parser,
     allowModifiers: boolean | undefined | null,
     decorators: Decorator[],
+    isFunctionParam: boolean = false,
   ): Pattern | TSParameterProperty {
     const left = this.parseMaybeDefault();
-    this.parseAssignableListItemTypes(left);
+    this.parseAssignableListItemTypes(left, isFunctionParam);
     const elt = this.parseMaybeDefault(left.loc.start, left);
     if (decorators.length) {
       left.decorators = decorators;
@@ -473,7 +492,11 @@ export default abstract class LValParser extends NodeUtils {
   }
 
   // Used by flow/typescript plugin to add type annotations to binding elements
-  parseAssignableListItemTypes(param: Pattern): Pattern {
+  parseAssignableListItemTypes(
+    param: Pattern,
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    isFunctionParam: boolean,
+  ): Pattern {
     return param;
   }
 

diff --git a/packages/babel-parser/src/parser/statement.ts b/packages/babel-parser/src/parser/statement.ts
@@ -1606,12 +1606,10 @@ export default abstract class StatementParser extends ExpressionParser {
   ): void {
     this.expect(tt.parenL);
     this.expressionScope.enter(newParameterDeclarationScope());
-    node.params = this.parseBindingList(
-      tt.parenR,
-      charCodes.rightParenthesis,
-      /* allowEmpty */ false,
+    node.params = this.parseBindingList(tt.parenR, charCodes.rightParenthesis, {
       allowModifiers,
-    );
+      isFunctionParams: true,
+    });
 
     this.expressionScope.exit();
   }

diff --git a/packages/babel-parser/src/plugins/typescript/index.ts b/packages/babel-parser/src/plugins/typescript/index.ts
@@ -755,7 +755,9 @@ export default (superClass: ClassWithMixin<typeof Parser, IJSXParserMixin>) =>
       N.Identifier | N.RestElement | N.ObjectPattern | N.ArrayPattern
     > {
       return super
-        .parseBindingList(tt.parenR, charCodes.rightParenthesis)
+        .parseBindingList(tt.parenR, charCodes.rightParenthesis, {
+          isFunctionParams: true,
+        })
         .map(pattern => {
           if (
             pattern.type !== "Identifier" &&
@@ -1419,11 +1421,9 @@ export default (superClass: ClassWithMixin<typeof Parser, IJSXParserMixin>) =>
         const { errors } = this.state;
         const previousErrorCount = errors.length;
         try {
-          super.parseBindingList(
-            tt.bracketR,
-            charCodes.rightSquareBracket,
-            true,
-          );
+          super.parseBindingList(tt.bracketR, charCodes.rightSquareBracket, {
+            allowEmpty: true,
+          });
           return errors.length === previousErrorCount;
         } catch {
           return false;
@@ -2251,6 +2251,7 @@ export default (superClass: ClassWithMixin<typeof Parser, IJSXParserMixin>) =>
     parseAssignableListItem(
       allowModifiers: boolean | undefined | null,
       decorators: N.Decorator[],
+      isFunctionParam: boolean,
     ): N.Pattern | N.TSParameterProperty {
       // Store original location to include modifiers in range
       const startLoc = this.state.startLoc;
@@ -2282,7 +2283,7 @@ export default (superClass: ClassWithMixin<typeof Parser, IJSXParserMixin>) =>
       }
 
       const left = this.parseMaybeDefault();
-      this.parseAssignableListItemTypes(left);
+      this.parseAssignableListItemTypes(left, isFunctionParam);
       const elt = this.parseMaybeDefault(left.loc.start, left);
       if (accessibility || readonly || override) {
         const pp = this.startNodeAt<N.TSParameterProperty>(startLoc);
@@ -2314,6 +2315,27 @@ export default (superClass: ClassWithMixin<typeof Parser, IJSXParserMixin>) =>
       );
     }
 
+    tsDisallowOptionalPattern(node: Undone<N.Function>) {
+      for (const param of node.params) {
+        if (
+          param.type !== "Identifier" &&
+          (param as any).optional &&
+          !this.state.isAmbientContext
+        ) {
+          this.raise(TSErrors.PatternIsOptional, { at: param });
+        }
+      }
+    }
+
+    setArrowFunctionParameters(
+      node: Undone<N.ArrowFunctionExpression>,
+      params: N.Expression[],
+      trailingCommaLoc?: Position | null,
+    ): void {
+      super.setArrowFunctionParameters(node, params, trailingCommaLoc);
+      this.tsDisallowOptionalPattern(node);
+    }
+
     parseFunctionBodyAndFinish<
       T extends
         | N.Function
@@ -2340,6 +2362,7 @@ export default (superClass: ClassWithMixin<typeof Parser, IJSXParserMixin>) =>
           return super.parseFunctionBodyAndFinish(node, bodilessType, isMethod);
         }
       }
+      this.tsDisallowOptionalPattern(node);
 
       return super.parseFunctionBodyAndFinish(node, type, isMethod);
     }
@@ -3504,16 +3527,10 @@ export default (superClass: ClassWithMixin<typeof Parser, IJSXParserMixin>) =>
     }
 
     // Allow type annotations inside of a parameter list.
-    parseAssignableListItemTypes(param: N.Pattern) {
-      if (this.eat(tt.question)) {
-        if (
-          param.type !== "Identifier" &&
-          !this.state.isAmbientContext &&
-          !this.state.inType
-        ) {
-          this.raise(TSErrors.PatternIsOptional, { at: param });
-        }
+    parseAssignableListItemTypes(param: N.Pattern, isFunctionParam: boolean) {
+      if (!isFunctionParam) return param;
 
+      if (this.eat(tt.question)) {
         (param as any as N.Identifier).optional = true;
       }
       const type = this.tsTryParseTypeAnnotation();

diff --git a/...-parser/test/fixtures/typescript/arrow-function/async-rest-optional-parameter/output.json b/...-parser/test/fixtures/typescript/arrow-function/async-rest-optional-parameter/output.json
@@ -1,6 +1,9 @@
 {
   "type": "File",
   "start":0,"end":34,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":34,"index":34}},
+  "errors": [
+    "SyntaxError: A binding pattern parameter cannot be optional in an implementation signature. (1:6)"
+  ],
   "program": {
     "type": "Program",
     "start":0,"end":34,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":34,"index":34}},

diff --git a/...babel-parser/test/fixtures/typescript/function/pattern-optional-parameters-arrow/input.ts b/...babel-parser/test/fixtures/typescript/function/pattern-optional-parameters-arrow/input.ts
@@ -0,0 +1 @@
+([]?, {}) => {}
diff --git a/...el-parser/test/fixtures/typescript/function/pattern-optional-parameters-arrow/output.json b/...el-parser/test/fixtures/typescript/function/pattern-optional-parameters-arrow/output.json
@@ -0,0 +1,46 @@
+{
+  "type": "File",
+  "start":0,"end":15,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":15,"index":15}},
+  "errors": [
+    "SyntaxError: A binding pattern parameter cannot be optional in an implementation signature. (1:1)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":15,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":15,"index":15}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":15,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":15,"index":15}},
+        "expression": {
+          "type": "ArrowFunctionExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":15,"index":15}},
+          "id": null,
+          "generator": false,
+          "async": false,
+          "params": [
+            {
+              "type": "ArrayPattern",
+              "start":1,"end":4,"loc":{"start":{"line":1,"column":1,"index":1},"end":{"line":1,"column":4,"index":4}},
+              "elements": [],
+              "optional": true
+            },
+            {
+              "type": "ObjectPattern",
+              "start":6,"end":8,"loc":{"start":{"line":1,"column":6,"index":6},"end":{"line":1,"column":8,"index":8}},
+              "properties": []
+            }
+          ],
+          "body": {
+            "type": "BlockStatement",
+            "start":13,"end":15,"loc":{"start":{"line":1,"column":13,"index":13},"end":{"line":1,"column":15,"index":15}},
+            "body": [],
+            "directives": []
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
diff --git a/...ript/function/pattern-parameters/input.ts → ...tion/pattern-optional-parameters/input.ts b/...ript/function/pattern-parameters/input.ts → ...tion/pattern-optional-parameters/input.ts
diff --git a/...t/function/pattern-parameters/output.json → ...n/pattern-optional-parameters/output.json b/...t/function/pattern-parameters/output.json → ...n/pattern-optional-parameters/output.json
diff --git a/...test/fixtures/typescript/scope/function-type-before-declaration-optional-pattern/input.ts b/...test/fixtures/typescript/scope/function-type-before-declaration-optional-pattern/input.ts
@@ -0,0 +1,4 @@
+function f({}?): void;
+function f() {}
+
+export { f };
diff --git a/...t/fixtures/typescript/scope/function-type-before-declaration-optional-pattern/output.json b/...t/fixtures/typescript/scope/function-type-before-declaration-optional-pattern/output.json
@@ -0,0 +1,82 @@
+{
+  "type": "File",
+  "start":0,"end":53,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":4,"column":13,"index":53}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":53,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":4,"column":13,"index":53}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "TSDeclareFunction",
+        "start":0,"end":22,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":22,"index":22}},
+        "id": {
+          "type": "Identifier",
+          "start":9,"end":10,"loc":{"start":{"line":1,"column":9,"index":9},"end":{"line":1,"column":10,"index":10},"identifierName":"f"},
+          "name": "f"
+        },
+        "generator": false,
+        "async": false,
+        "params": [
+          {
+            "type": "ObjectPattern",
+            "start":11,"end":14,"loc":{"start":{"line":1,"column":11,"index":11},"end":{"line":1,"column":14,"index":14}},
+            "properties": [],
+            "optional": true
+          }
+        ],
+        "returnType": {
+          "type": "TSTypeAnnotation",
+          "start":15,"end":21,"loc":{"start":{"line":1,"column":15,"index":15},"end":{"line":1,"column":21,"index":21}},
+          "typeAnnotation": {
+            "type": "TSVoidKeyword",
+            "start":17,"end":21,"loc":{"start":{"line":1,"column":17,"index":17},"end":{"line":1,"column":21,"index":21}}
+          }
+        }
+      },
+      {
+        "type": "FunctionDeclaration",
+        "start":23,"end":38,"loc":{"start":{"line":2,"column":0,"index":23},"end":{"line":2,"column":15,"index":38}},
+        "id": {
+          "type": "Identifier",
+          "start":32,"end":33,"loc":{"start":{"line":2,"column":9,"index":32},"end":{"line":2,"column":10,"index":33},"identifierName":"f"},
+          "name": "f"
+        },
+        "generator": false,
+        "async": false,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start":36,"end":38,"loc":{"start":{"line":2,"column":13,"index":36},"end":{"line":2,"column":15,"index":38}},
+          "body": [],
+          "directives": []
+        }
+      },
+      {
+        "type": "ExportNamedDeclaration",
+        "start":40,"end":53,"loc":{"start":{"line":4,"column":0,"index":40},"end":{"line":4,"column":13,"index":53}},
+        "exportKind": "value",
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start":49,"end":50,"loc":{"start":{"line":4,"column":9,"index":49},"end":{"line":4,"column":10,"index":50}},
+            "local": {
+              "type": "Identifier",
+              "start":49,"end":50,"loc":{"start":{"line":4,"column":9,"index":49},"end":{"line":4,"column":10,"index":50},"identifierName":"f"},
+              "name": "f"
+            },
+            "exportKind": "value",
+            "exported": {
+              "type": "Identifier",
+              "start":49,"end":50,"loc":{"start":{"line":4,"column":9,"index":49},"end":{"line":4,"column":10,"index":50},"identifierName":"f"},
+              "name": "f"
+            }
+          }
+        ],
+        "source": null,
+        "declaration": null
+      }
+    ],
+    "directives": []
+  }
+}
diff --git a/packages/babel-parser/test/fixtures/typescript/types/no-annotation-in-destructuring/input.ts b/packages/babel-parser/test/fixtures/typescript/types/no-annotation-in-destructuring/input.ts
@@ -0,0 +1 @@
+let [a: number] = b;
diff --git a/...s/babel-parser/test/fixtures/typescript/types/no-annotation-in-destructuring/options.json b/...s/babel-parser/test/fixtures/typescript/types/no-annotation-in-destructuring/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Unexpected token, expected \",\" (1:6)"
+}
diff --git a/...bel-parser/test/fixtures/typescript/types/no-optional-in-destructuring-in-params/input.ts b/...bel-parser/test/fixtures/typescript/types/no-optional-in-destructuring-in-params/input.ts
@@ -0,0 +1 @@
+function f([a: number]) {}
diff --git a/...parser/test/fixtures/typescript/types/no-optional-in-destructuring-in-params/options.json b/...parser/test/fixtures/typescript/types/no-optional-in-destructuring-in-params/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Unexpected token, expected \",\" (1:13)"
+}
diff --git a/packages/babel-parser/test/fixtures/typescript/types/no-optional-in-destructuring/input.ts b/packages/babel-parser/test/fixtures/typescript/types/no-optional-in-destructuring/input.ts
@@ -0,0 +1 @@
+let [a: number] = b;
diff --git a/...ges/babel-parser/test/fixtures/typescript/types/no-optional-in-destructuring/options.json b/...ges/babel-parser/test/fixtures/typescript/types/no-optional-in-destructuring/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Unexpected token, expected \",\" (1:6)"
+}