Disallow destructured parameter properties

src/compiler/checker.ts

@@ -7189,7 +7189,7 @@ module ts {
 
             checkVariableLikeDeclaration(node);
             var func = getContainingFunction(node);
-            if (node.flags & (NodeFlags.Public | NodeFlags.Private | NodeFlags.Protected)) {
+            if (node.flags & NodeFlags.AccessibilityModifier) {
                 func = getContainingFunction(node);
                 if (!(func.kind === SyntaxKind.Constructor && nodeIsPresent(func.body))) {
                     error(node, Diagnostics.A_parameter_property_is_only_allowed_in_a_constructor_implementation);
@@ -7208,17 +7208,20 @@ module ts {
                 checkGrammarIndexSignature(<SignatureDeclaration>node);
             }
             // TODO (yuisu): Remove this check in else-if when SyntaxKind.Construct is moved and ambient context is handled
-            else  if (node.kind === SyntaxKind.FunctionType || node.kind === SyntaxKind.FunctionDeclaration || node.kind === SyntaxKind.ConstructorType ||
+            else if (node.kind === SyntaxKind.FunctionType || node.kind === SyntaxKind.FunctionDeclaration || node.kind === SyntaxKind.ConstructorType ||
                       node.kind === SyntaxKind.CallSignature || node.kind === SyntaxKind.Constructor ||
                       node.kind === SyntaxKind.ConstructSignature){
                 checkGrammarFunctionLikeDeclaration(<FunctionLikeDeclaration>node);
             }
 
             checkTypeParameters(node.typeParameters);
+
             forEach(node.parameters, checkParameter);
+
             if (node.type) {
                 checkSourceElement(node.type);
             }
+
             if (produceDiagnostics) {
                 checkCollisionWithArgumentsInGeneratedCode(node);
                 if (compilerOptions.noImplicitAny && !node.type) {
@@ -10169,6 +10172,9 @@ module ts {
             else if (node.kind === SyntaxKind.InterfaceDeclaration && flags & NodeFlags.Ambient) {
                 return grammarErrorOnNode(lastDeclare, Diagnostics.A_declare_modifier_cannot_be_used_with_an_interface_declaration, "declare");
             }
+            else if (node.kind === SyntaxKind.Parameter && (flags & NodeFlags.AccessibilityModifier) && isBindingPattern((<ParameterDeclaration>node).name)) {
+                return grammarErrorOnNode(node, Diagnostics.A_parameter_property_may_not_be_a_binding_pattern);
+            }
         }
 
         function checkGrammarForDisallowedTrailingComma(list: NodeArray<Node>): boolean {

src/compiler/diagnosticInformationMap.generated.ts

@@ -146,6 +146,7 @@ module ts {
         Modifiers_cannot_appear_here: { code: 1184, category: DiagnosticCategory.Error, key: "Modifiers cannot appear here." },
         Merge_conflict_marker_encountered: { code: 1185, category: DiagnosticCategory.Error, key: "Merge conflict marker encountered." },
         A_rest_element_cannot_have_an_initializer: { code: 1186, category: DiagnosticCategory.Error, key: "A rest element cannot have an initializer." },
+        A_parameter_property_may_not_be_a_binding_pattern: { code: 1187, category: DiagnosticCategory.Error, key: "A parameter property may not be a binding pattern." },
         Duplicate_identifier_0: { code: 2300, category: DiagnosticCategory.Error, key: "Duplicate identifier '{0}'." },
         Initializer_of_instance_member_variable_0_cannot_reference_identifier_1_declared_in_the_constructor: { code: 2301, category: DiagnosticCategory.Error, key: "Initializer of instance member variable '{0}' cannot reference identifier '{1}' declared in the constructor." },
         Static_members_cannot_reference_class_type_parameters: { code: 2302, category: DiagnosticCategory.Error, key: "Static members cannot reference class type parameters." },

src/compiler/diagnosticMessages.json

@@ -224,7 +224,7 @@
     "A 'declare' modifier cannot be used with an import declaration.": {
         "category": "Error",
         "code": 1079,
-        "isEarly":  true
+        "isEarly": true
     },
     "Invalid 'reference' directive syntax.": {
         "category": "Error",
@@ -659,7 +659,7 @@
     "An implementation cannot be declared in ambient contexts.": {
         "category": "Error",
         "code": 1184,
-        "isEarly":  true
+        "isEarly": true
     },
     "Modifiers cannot appear here.": {
         "category": "Error",
@@ -673,6 +673,10 @@
         "category": "Error",
         "code": 1186
     },
+    "A parameter property may not be a binding pattern.": {
+        "category": "Error",
+        "code":  1187
+    },
 
     "Duplicate identifier '{0}'.": {
         "category": "Error",

src/compiler/parser.ts

@@ -1395,7 +1395,10 @@ module ts {
         }
 
         function canFollowModifier(): boolean {
-            return token === SyntaxKind.OpenBracketToken || token === SyntaxKind.AsteriskToken || isLiteralPropertyName();
+            return token === SyntaxKind.OpenBracketToken
+                || token === SyntaxKind.OpenBraceToken
+                || token === SyntaxKind.AsteriskToken
+                || isLiteralPropertyName();
         }
 
         // True if positioned at the start of a list element

tests/baselines/reference/destructuringParameterProperties1.errors.txt

@@ -0,0 +1,71 @@
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties1.ts(2,17): error TS1187: A parameter property may not be a binding pattern.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties1.ts(9,17): error TS1187: A parameter property may not be a binding pattern.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties1.ts(16,17): error TS1187: A parameter property may not be a binding pattern.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties1.ts(22,26): error TS2339: Property 'x' does not exist on type 'C1'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties1.ts(22,35): error TS2339: Property 'y' does not exist on type 'C1'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties1.ts(22,43): error TS2339: Property 'y' does not exist on type 'C1'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties1.ts(22,52): error TS2339: Property 'z' does not exist on type 'C1'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties1.ts(25,30): error TS2339: Property 'x' does not exist on type 'C2'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties1.ts(25,36): error TS2339: Property 'y' does not exist on type 'C2'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties1.ts(25,42): error TS2339: Property 'z' does not exist on type 'C2'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties1.ts(29,30): error TS2339: Property 'x' does not exist on type 'C3'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties1.ts(29,36): error TS2339: Property 'y' does not exist on type 'C3'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties1.ts(29,42): error TS2339: Property 'z' does not exist on type 'C3'.
+
+
+==== tests/cases/conformance/es6/destructuring/destructuringParameterProperties1.ts (13 errors) ====
+    class C1 {
+        constructor(public [x, y, z]: string[]) {
+                    ~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1187: A parameter property may not be a binding pattern.
+        }
+    }
+
+    type TupleType1 = [string, number, boolean];
+
+    class C2 {
+        constructor(public [x, y, z]: TupleType1) {
+                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1187: A parameter property may not be a binding pattern.
+        }
+    }
+
+    type ObjType1 = { x: number; y: string; z: boolean }
+
+    class C3 {
+        constructor(public { x, y, z }: ObjType1) {
+                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1187: A parameter property may not be a binding pattern.
+        }
+    }
+
+    var c1 = new C1([]);
+    c1 = new C1(["larry", "{curly}", "moe"]);
+    var useC1Properties = c1.x === c1.y && c1.y === c1.z;
+                             ~
+!!! error TS2339: Property 'x' does not exist on type 'C1'.
+                                      ~
+!!! error TS2339: Property 'y' does not exist on type 'C1'.
+                                              ~
+!!! error TS2339: Property 'y' does not exist on type 'C1'.
+                                                       ~
+!!! error TS2339: Property 'z' does not exist on type 'C1'.
+
+    var c2 = new C2(["10", 10, !!10]);
+    var [c2_x, c2_y, c2_z] = [c2.x, c2.y, c2.z];
+                                 ~
+!!! error TS2339: Property 'x' does not exist on type 'C2'.
+                                       ~
+!!! error TS2339: Property 'y' does not exist on type 'C2'.
+                                             ~
+!!! error TS2339: Property 'z' does not exist on type 'C2'.
+
+    var c3 = new C3({x: 0, y: "", z: false});
+    c3 = new C3({x: 0, "y": "y", z: true});
+    var [c3_x, c3_y, c3_z] = [c3.x, c3.y, c3.z];
+                                 ~
+!!! error TS2339: Property 'x' does not exist on type 'C3'.
+                                       ~
+!!! error TS2339: Property 'y' does not exist on type 'C3'.
+                                             ~
+!!! error TS2339: Property 'z' does not exist on type 'C3'.

tests/baselines/reference/destructuringParameterProperties1.js

@@ -0,0 +1,61 @@
+//// [destructuringParameterProperties1.ts]
+class C1 {
+    constructor(public [x, y, z]: string[]) {
+    }
+}
+
+type TupleType1 = [string, number, boolean];
+
+class C2 {
+    constructor(public [x, y, z]: TupleType1) {
+    }
+}
+
+type ObjType1 = { x: number; y: string; z: boolean }
+
+class C3 {
+    constructor(public { x, y, z }: ObjType1) {
+    }
+}
+
+var c1 = new C1([]);
+c1 = new C1(["larry", "{curly}", "moe"]);
+var useC1Properties = c1.x === c1.y && c1.y === c1.z;
+
+var c2 = new C2(["10", 10, !!10]);
+var [c2_x, c2_y, c2_z] = [c2.x, c2.y, c2.z];
+
+var c3 = new C3({x: 0, y: "", z: false});
+c3 = new C3({x: 0, "y": "y", z: true});
+var [c3_x, c3_y, c3_z] = [c3.x, c3.y, c3.z];
+
+//// [destructuringParameterProperties1.js]
+var C1 = (function () {
+    function C1(_a) {
+        var x = _a[0], y = _a[1], z = _a[2];
+        this.[x, y, z] = [x, y, z];
+    }
+    return C1;
+})();
+var C2 = (function () {
+    function C2(_a) {
+        var x = _a[0], y = _a[1], z = _a[2];
+        this.[x, y, z] = [x, y, z];
+    }
+    return C2;
+})();
+var C3 = (function () {
+    function C3(_a) {
+        var x = _a.x, y = _a.y, z = _a.z;
+        this.{ x, y, z } = { x, y, z };
+    }
+    return C3;
+})();
+var c1 = new C1([]);
+c1 = new C1(["larry", "{curly}", "moe"]);
+var useC1Properties = c1.x === c1.y && c1.y === c1.z;
+var c2 = new C2(["10", 10, !!10]);
+var _a = [c2.x, c2.y, c2.z], c2_x = _a[0], c2_y = _a[1], c2_z = _a[2];
+var c3 = new C3({ x: 0, y: "", z: false });
+c3 = new C3({ x: 0, "y": "y", z: true });
+var _b = [c3.x, c3.y, c3.z], c3_x = _b[0], c3_y = _b[1], c3_z = _b[2];

tests/baselines/reference/destructuringParameterProperties2.errors.txt

@@ -0,0 +1,56 @@
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties2.ts(2,36): error TS1187: A parameter property may not be a binding pattern.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties2.ts(3,59): error TS2339: Property 'b' does not exist on type 'C1'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties2.ts(3,83): error TS2339: Property 'c' does not exist on type 'C1'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties2.ts(4,18): error TS2339: Property 'a' does not exist on type 'C1'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties2.ts(9,21): error TS2339: Property 'a' does not exist on type 'C1'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties2.ts(13,21): error TS2339: Property 'b' does not exist on type 'C1'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties2.ts(17,21): error TS2339: Property 'c' does not exist on type 'C1'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties2.ts(21,27): error TS2345: Argument of type '[number, undefined, string]' is not assignable to parameter of type '[number, string, boolean]'.
+
+
+==== tests/cases/conformance/es6/destructuring/destructuringParameterProperties2.ts (8 errors) ====
+    class C1 {
+        constructor(private k: number, private [a, b, c]: [number, string, boolean]) {
+                                       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1187: A parameter property may not be a binding pattern.
+            if ((b === undefined && c === undefined) || (this.b === undefined && this.c === undefined)) {
+                                                              ~
+!!! error TS2339: Property 'b' does not exist on type 'C1'.
+                                                                                      ~
+!!! error TS2339: Property 'c' does not exist on type 'C1'.
+                this.a = a || k;
+                     ~
+!!! error TS2339: Property 'a' does not exist on type 'C1'.
+            }
+        }
+
+        public getA() {
+            return this.a
+                        ~
+!!! error TS2339: Property 'a' does not exist on type 'C1'.
+        }
+
+        public getB() {
+            return this.b
+                        ~
+!!! error TS2339: Property 'b' does not exist on type 'C1'.
+        }
+
+        public getC() {
+            return this.c;
+                        ~
+!!! error TS2339: Property 'c' does not exist on type 'C1'.
+        }
+    }
+
+    var x = new C1(undefined, [0, undefined, ""]);
+                              ~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '[number, undefined, string]' is not assignable to parameter of type '[number, string, boolean]'.
+    var [x_a, x_b, x_c] = [x.getA(), x.getB(), x.getC()];
+
+    var y = new C1(10, [0, "", true]);
+    var [y_a, y_b, y_c] = [y.getA(), y.getB(), y.getC()];
+
+    var z = new C1(10, [undefined, "", null]);
+    var [z_a, z_b, z_c] = [z.getA(), z.getB(), z.getC()];
+

tests/baselines/reference/destructuringParameterProperties2.js

@@ -0,0 +1,58 @@
+//// [destructuringParameterProperties2.ts]
+class C1 {
+    constructor(private k: number, private [a, b, c]: [number, string, boolean]) {
+        if ((b === undefined && c === undefined) || (this.b === undefined && this.c === undefined)) {
+            this.a = a || k;
+        }
+    }
+
+    public getA() {
+        return this.a
+    }
+
+    public getB() {
+        return this.b
+    }
+
+    public getC() {
+        return this.c;
+    }
+}
+
+var x = new C1(undefined, [0, undefined, ""]);
+var [x_a, x_b, x_c] = [x.getA(), x.getB(), x.getC()];
+
+var y = new C1(10, [0, "", true]);
+var [y_a, y_b, y_c] = [y.getA(), y.getB(), y.getC()];
+
+var z = new C1(10, [undefined, "", null]);
+var [z_a, z_b, z_c] = [z.getA(), z.getB(), z.getC()];
+
+
+//// [destructuringParameterProperties2.js]
+var C1 = (function () {
+    function C1(k, _a) {
+        var a = _a[0], b = _a[1], c = _a[2];
+        this.k = k;
+        this.[a, b, c] = [a, b, c];
+        if ((b === undefined && c === undefined) || (this.b === undefined && this.c === undefined)) {
+            this.a = a || k;
+        }
+    }
+    C1.prototype.getA = function () {
+        return this.a;
+    };
+    C1.prototype.getB = function () {
+        return this.b;
+    };
+    C1.prototype.getC = function () {
+        return this.c;
+    };
+    return C1;
+})();
+var x = new C1(undefined, [0, undefined, ""]);
+var _a = [x.getA(), x.getB(), x.getC()], x_a = _a[0], x_b = _a[1], x_c = _a[2];
+var y = new C1(10, [0, "", true]);
+var _b = [y.getA(), y.getB(), y.getC()], y_a = _b[0], y_b = _b[1], y_c = _b[2];
+var z = new C1(10, [undefined, "", null]);
+var _c = [z.getA(), z.getB(), z.getC()], z_a = _c[0], z_b = _c[1], z_c = _c[2];

tests/baselines/reference/destructuringParameterProperties3.errors.txt

@@ -0,0 +1,56 @@
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties3.ts(2,31): error TS1187: A parameter property may not be a binding pattern.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties3.ts(3,59): error TS2339: Property 'b' does not exist on type 'C1<T, U, V>'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties3.ts(3,83): error TS2339: Property 'c' does not exist on type 'C1<T, U, V>'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties3.ts(4,18): error TS2339: Property 'a' does not exist on type 'C1<T, U, V>'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties3.ts(9,21): error TS2339: Property 'a' does not exist on type 'C1<T, U, V>'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties3.ts(13,21): error TS2339: Property 'b' does not exist on type 'C1<T, U, V>'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties3.ts(17,21): error TS2339: Property 'c' does not exist on type 'C1<T, U, V>'.
+
+
+==== tests/cases/conformance/es6/destructuring/destructuringParameterProperties3.ts (7 errors) ====
+    class C1<T, U, V> {
+        constructor(private k: T, private [a, b, c]: [T,U,V]) {
+                                  ~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1187: A parameter property may not be a binding pattern.
+            if ((b === undefined && c === undefined) || (this.b === undefined && this.c === undefined)) {
+                                                              ~
+!!! error TS2339: Property 'b' does not exist on type 'C1<T, U, V>'.
+                                                                                      ~
+!!! error TS2339: Property 'c' does not exist on type 'C1<T, U, V>'.
+                this.a = a || k;
+                     ~
+!!! error TS2339: Property 'a' does not exist on type 'C1<T, U, V>'.
+            }
+        }
+
+        public getA() {
+            return this.a
+                        ~
+!!! error TS2339: Property 'a' does not exist on type 'C1<T, U, V>'.
+        }
+
+        public getB() {
+            return this.b
+                        ~
+!!! error TS2339: Property 'b' does not exist on type 'C1<T, U, V>'.
+        }
+
+        public getC() {
+            return this.c;
+                        ~
+!!! error TS2339: Property 'c' does not exist on type 'C1<T, U, V>'.
+        }
+    }
+
+    var x = new C1(undefined, [0, true, ""]);
+    var [x_a, x_b, x_c] = [x.getA(), x.getB(), x.getC()];
+
+    var y = new C1(10, [0, true, true]);
+    var [y_a, y_b, y_c] = [y.getA(), y.getB(), y.getC()];
+
+    var z = new C1(10, [undefined, "", ""]);
+    var [z_a, z_b, z_c] = [z.getA(), z.getB(), z.getC()];
+
+    var w = new C1(10, [undefined, undefined, undefined]);
+    var [z_a, z_b, z_c] = [z.getA(), z.getB(), z.getC()];
+