Fix decorator emit crash (microsoft#60224)

Author: rbuckton

src/compiler/transformers/esDecorators.ts

@@ -686,7 +686,7 @@ export function transformESDecorators(context: TransformationContext): (x: Sourc
         let shouldTransformPrivateStaticElementsInClass = false;
 
         // 1. Class decorators are evaluated outside of the private name scope of the class.
-        const classDecorators = transformAllDecoratorsOfDeclaration(getAllDecoratorsOfClass(node));
+        const classDecorators = transformAllDecoratorsOfDeclaration(getAllDecoratorsOfClass(node, /*useLegacyDecorators*/ false));
         if (classDecorators) {
             // - Since class decorators don't have privileged access to private names defined inside the class,
             //   they must be evaluated outside of the class body.

src/compiler/transformers/legacyDecorators.ts

@@ -679,7 +679,7 @@ export function transformLegacyDecorators(context: TransformationContext): (x: S
      * @param node The class node.
      */
     function generateConstructorDecorationExpression(node: ClassExpression | ClassDeclaration) {
-        const allDecorators = getAllDecoratorsOfClass(node);
+        const allDecorators = getAllDecoratorsOfClass(node, /*useLegacyDecorators*/ true);
         const decoratorExpressions = transformAllDecoratorsOfDeclaration(allDecorators);
         if (!decoratorExpressions) {
             return undefined;

src/compiler/transformers/utilities.ts

@@ -679,9 +679,9 @@ function getDecoratorsOfParameters(node: FunctionLikeDeclaration | undefined) {
  *
  * @internal
  */
-export function getAllDecoratorsOfClass(node: ClassLikeDeclaration): AllDecorators | undefined {
+export function getAllDecoratorsOfClass(node: ClassLikeDeclaration, useLegacyDecorators: boolean): AllDecorators | undefined {
     const decorators = getDecorators(node);
-    const parameters = getDecoratorsOfParameters(getFirstConstructorWithBody(node));
+    const parameters = useLegacyDecorators ? getDecoratorsOfParameters(getFirstConstructorWithBody(node)) : undefined;
     if (!some(decorators) && !some(parameters)) {
         return undefined;
     }
@@ -705,12 +705,12 @@ export function getAllDecoratorsOfClassElement(member: ClassElement, parent: Cla
         case SyntaxKind.GetAccessor:
         case SyntaxKind.SetAccessor:
             if (!useLegacyDecorators) {
-                return getAllDecoratorsOfMethod(member as AccessorDeclaration);
+                return getAllDecoratorsOfMethod(member as AccessorDeclaration, /*useLegacyDecorators*/ false);
             }
-            return getAllDecoratorsOfAccessors(member as AccessorDeclaration, parent);
+            return getAllDecoratorsOfAccessors(member as AccessorDeclaration, parent, /*useLegacyDecorators*/ true);
 
         case SyntaxKind.MethodDeclaration:
-            return getAllDecoratorsOfMethod(member as MethodDeclaration);
+            return getAllDecoratorsOfMethod(member as MethodDeclaration, useLegacyDecorators);
 
         case SyntaxKind.PropertyDeclaration:
             return getAllDecoratorsOfProperty(member as PropertyDeclaration);
@@ -726,7 +726,7 @@ export function getAllDecoratorsOfClassElement(member: ClassElement, parent: Cla
  * @param parent The class node that contains the accessor.
  * @param accessor The class accessor member.
  */
-function getAllDecoratorsOfAccessors(accessor: AccessorDeclaration, parent: ClassExpression | ClassDeclaration): AllDecorators | undefined {
+function getAllDecoratorsOfAccessors(accessor: AccessorDeclaration, parent: ClassExpression | ClassDeclaration, useLegacyDecorators: boolean): AllDecorators | undefined {
     if (!accessor.body) {
         return undefined;
     }
@@ -741,7 +741,7 @@ function getAllDecoratorsOfAccessors(accessor: AccessorDeclaration, parent: Clas
     }
 
     const decorators = getDecorators(firstAccessorWithDecorators);
-    const parameters = getDecoratorsOfParameters(setAccessor);
+    const parameters = useLegacyDecorators ? getDecoratorsOfParameters(setAccessor) : undefined;
     if (!some(decorators) && !some(parameters)) {
         return undefined;
     }
@@ -759,13 +759,13 @@ function getAllDecoratorsOfAccessors(accessor: AccessorDeclaration, parent: Clas
  *
  * @param method The class method member.
  */
-function getAllDecoratorsOfMethod(method: MethodDeclaration | AccessorDeclaration): AllDecorators | undefined {
+function getAllDecoratorsOfMethod(method: MethodDeclaration | AccessorDeclaration, useLegacyDecorators: boolean): AllDecorators | undefined {
     if (!method.body) {
         return undefined;
     }
 
     const decorators = getDecorators(method);
-    const parameters = getDecoratorsOfParameters(method);
+    const parameters = useLegacyDecorators ? getDecoratorsOfParameters(method) : undefined;
     if (!some(decorators) && !some(parameters)) {
         return undefined;
     }

tests/baselines/reference/parameterDecoratorsEmitCrash.errors.txt

@@ -0,0 +1,14 @@
+parameterDecoratorsEmitCrash.ts(6,17): error TS1206: Decorators are not valid here.
+
+
+==== parameterDecoratorsEmitCrash.ts (1 errors) ====
+    // https://github.com/microsoft/TypeScript/issues/58269
+    declare var dec: any;
+    
+    export class C {
+        @dec x: any;
+        constructor(@dec x: any) {}
+                    ~
+!!! error TS1206: Decorators are not valid here.
+    }
+    

tests/baselines/reference/parameterDecoratorsEmitCrash.js

@@ -0,0 +1,71 @@
+//// [tests/cases/compiler/parameterDecoratorsEmitCrash.ts] ////
+
+//// [parameterDecoratorsEmitCrash.ts]
+// https://github.com/microsoft/TypeScript/issues/58269
+declare var dec: any;
+
+export class C {
+    @dec x: any;
+    constructor(@dec x: any) {}
+}
+
+
+//// [parameterDecoratorsEmitCrash.js]
+"use strict";
+var __esDecorate = (this && this.__esDecorate) || function (ctor, descriptorIn, decorators, contextIn, initializers, extraInitializers) {
+    function accept(f) { if (f !== void 0 && typeof f !== "function") throw new TypeError("Function expected"); return f; }
+    var kind = contextIn.kind, key = kind === "getter" ? "get" : kind === "setter" ? "set" : "value";
+    var target = !descriptorIn && ctor ? contextIn["static"] ? ctor : ctor.prototype : null;
+    var descriptor = descriptorIn || (target ? Object.getOwnPropertyDescriptor(target, contextIn.name) : {});
+    var _, done = false;
+    for (var i = decorators.length - 1; i >= 0; i--) {
+        var context = {};
+        for (var p in contextIn) context[p] = p === "access" ? {} : contextIn[p];
+        for (var p in contextIn.access) context.access[p] = contextIn.access[p];
+        context.addInitializer = function (f) { if (done) throw new TypeError("Cannot add initializers after decoration has completed"); extraInitializers.push(accept(f || null)); };
+        var result = (0, decorators[i])(kind === "accessor" ? { get: descriptor.get, set: descriptor.set } : descriptor[key], context);
+        if (kind === "accessor") {
+            if (result === void 0) continue;
+            if (result === null || typeof result !== "object") throw new TypeError("Object expected");
+            if (_ = accept(result.get)) descriptor.get = _;
+            if (_ = accept(result.set)) descriptor.set = _;
+            if (_ = accept(result.init)) initializers.unshift(_);
+        }
+        else if (_ = accept(result)) {
+            if (kind === "field") initializers.unshift(_);
+            else descriptor[key] = _;
+        }
+    }
+    if (target) Object.defineProperty(target, contextIn.name, descriptor);
+    done = true;
+};
+var __runInitializers = (this && this.__runInitializers) || function (thisArg, initializers, value) {
+    var useValue = arguments.length > 2;
+    for (var i = 0; i < initializers.length; i++) {
+        value = useValue ? initializers[i].call(thisArg, value) : initializers[i].call(thisArg);
+    }
+    return useValue ? value : void 0;
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.C = void 0;
+var C = function () {
+    var _a;
+    var _x_decorators;
+    var _x_initializers = [];
+    var _x_extraInitializers = [];
+    return _a = /** @class */ (function () {
+            function C(x) {
+                this.x = __runInitializers(this, _x_initializers, void 0);
+                __runInitializers(this, _x_extraInitializers);
+            }
+            return C;
+        }()),
+        (function () {
+            var _metadata = typeof Symbol === "function" && Symbol.metadata ? Object.create(null) : void 0;
+            _x_decorators = [dec];
+            __esDecorate(null, null, _x_decorators, { kind: "field", name: "x", static: false, private: false, access: { has: function (obj) { return "x" in obj; }, get: function (obj) { return obj.x; }, set: function (obj, value) { obj.x = value; } }, metadata: _metadata }, _x_initializers, _x_extraInitializers);
+            if (_metadata) Object.defineProperty(_a, Symbol.metadata, { enumerable: true, configurable: true, writable: true, value: _metadata });
+        })(),
+        _a;
+}();
+exports.C = C;

tests/cases/compiler/parameterDecoratorsEmitCrash.ts

@@ -0,0 +1,9 @@
+// @noTypesAndSymbols: true
+
+// https://github.com/microsoft/TypeScript/issues/58269
+declare var dec: any;
+
+export class C {
+    @dec x: any;
+    constructor(@dec x: any) {}
+}