Correctly emit bidning pattern with initializer and rest

Author: Yui T

src/compiler/declarationEmitter.ts

@@ -1291,8 +1291,10 @@ module ts {
                 write("...");
             }
             if (isBindingPattern(node.name)) {
-                // By emitting binding pattern as binding pattern in function parameters, language service can provide better signature help
-                write(getTextOfNode(node.name));
+                // For bindingPattern, we can't simply writeTextOfNode from the source file
+                // because we want to omit the initializer and using writeTextOfNode will result in initializer get emitted.
+                // Therefore, we will have to recursively emit each element in the bindingPattern.
+                emitBindingPattern(<BindingPattern>node.name);
             }
             else {
                 writeTextOfNode(currentSourceFile, node.name);
@@ -1312,72 +1314,127 @@ module ts {
             }
 
             function getParameterDeclarationTypeVisibilityError(symbolAccesibilityResult: SymbolAccessiblityResult): SymbolAccessibilityDiagnostic {
-                let diagnosticMessage: DiagnosticMessage;
+                let diagnosticMessage: DiagnosticMessage = getParameterDeclarationTypeVisibilityDiagnosticMessage(symbolAccesibilityResult);
+                return diagnosticMessage !== undefined ? {
+                    diagnosticMessage,
+                    errorNode: node,
+                    typeName: node.name
+                } : undefined;
+            }
+
+            function getParameterDeclarationTypeVisibilityDiagnosticMessage(symbolAccesibilityResult: SymbolAccessiblityResult) {
                 switch (node.parent.kind) {
                     case SyntaxKind.Constructor:
-                        diagnosticMessage = symbolAccesibilityResult.errorModuleName ?
+                        return symbolAccesibilityResult.errorModuleName ?
                             symbolAccesibilityResult.accessibility === SymbolAccessibility.CannotBeNamed ?
                                 Diagnostics.Parameter_0_of_constructor_from_exported_class_has_or_is_using_name_1_from_external_module_2_but_cannot_be_named :
                                 Diagnostics.Parameter_0_of_constructor_from_exported_class_has_or_is_using_name_1_from_private_module_2 :
                             Diagnostics.Parameter_0_of_constructor_from_exported_class_has_or_is_using_private_name_1;
-                        break;
 
                     case SyntaxKind.ConstructSignature:
                         // Interfaces cannot have parameter types that cannot be named
-                        diagnosticMessage = symbolAccesibilityResult.errorModuleName ?
+                        return symbolAccesibilityResult.errorModuleName ?
                             Diagnostics.Parameter_0_of_constructor_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2 :
                             Diagnostics.Parameter_0_of_constructor_signature_from_exported_interface_has_or_is_using_private_name_1;
-                        break;
 
                     case SyntaxKind.CallSignature:
                         // Interfaces cannot have parameter types that cannot be named
-                        diagnosticMessage = symbolAccesibilityResult.errorModuleName ?
+                        return symbolAccesibilityResult.errorModuleName ?
                             Diagnostics.Parameter_0_of_call_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2 :
                             Diagnostics.Parameter_0_of_call_signature_from_exported_interface_has_or_is_using_private_name_1;
-                        break;
 
                     case SyntaxKind.MethodDeclaration:
                     case SyntaxKind.MethodSignature:
                         if (node.parent.flags & NodeFlags.Static) {
-                            diagnosticMessage = symbolAccesibilityResult.errorModuleName ?
+                            return symbolAccesibilityResult.errorModuleName ?
                                 symbolAccesibilityResult.accessibility === SymbolAccessibility.CannotBeNamed ?
                                     Diagnostics.Parameter_0_of_public_static_method_from_exported_class_has_or_is_using_name_1_from_external_module_2_but_cannot_be_named :
                                     Diagnostics.Parameter_0_of_public_static_method_from_exported_class_has_or_is_using_name_1_from_private_module_2 :
                                 Diagnostics.Parameter_0_of_public_static_method_from_exported_class_has_or_is_using_private_name_1;
                         }
                         else if (node.parent.parent.kind === SyntaxKind.ClassDeclaration) {
-                            diagnosticMessage = symbolAccesibilityResult.errorModuleName ?
+                             return symbolAccesibilityResult.errorModuleName ?
                                 symbolAccesibilityResult.accessibility === SymbolAccessibility.CannotBeNamed ?
                                     Diagnostics.Parameter_0_of_public_method_from_exported_class_has_or_is_using_name_1_from_external_module_2_but_cannot_be_named :
                                     Diagnostics.Parameter_0_of_public_method_from_exported_class_has_or_is_using_name_1_from_private_module_2 :
                                 Diagnostics.Parameter_0_of_public_method_from_exported_class_has_or_is_using_private_name_1;
                         }
                         else {
                             // Interfaces cannot have parameter types that cannot be named
-                            diagnosticMessage = symbolAccesibilityResult.errorModuleName ?
+                            return symbolAccesibilityResult.errorModuleName ?
                                 Diagnostics.Parameter_0_of_method_from_exported_interface_has_or_is_using_name_1_from_private_module_2 :
                                 Diagnostics.Parameter_0_of_method_from_exported_interface_has_or_is_using_private_name_1;
                         }
-                        break;
 
                     case SyntaxKind.FunctionDeclaration:
-                        diagnosticMessage = symbolAccesibilityResult.errorModuleName ?
+                        return symbolAccesibilityResult.errorModuleName ?
                             symbolAccesibilityResult.accessibility === SymbolAccessibility.CannotBeNamed ?
                                 Diagnostics.Parameter_0_of_exported_function_has_or_is_using_name_1_from_external_module_2_but_cannot_be_named :
                                 Diagnostics.Parameter_0_of_exported_function_has_or_is_using_name_1_from_private_module_2 :
                             Diagnostics.Parameter_0_of_exported_function_has_or_is_using_private_name_1;
-                        break;
 
                     default:
                         Debug.fail("This is unknown parent for parameter: " + node.parent.kind);
                 }
+            }
 
-                return {
-                    diagnosticMessage,
-                    errorNode: node,
-                    typeName: node.name
-                };
+            function emitBindingPattern(bindingPattern: BindingPattern) {
+                // We have to explicitly emit square bracket and bracket because these tokens are not store inside the node.
+                if (bindingPattern.kind === SyntaxKind.ObjectBindingPattern) {
+                    write("{");
+                    emitCommaList(bindingPattern.elements, emitBindingElement);
+                    write("}");
+                }
+                else if (bindingPattern.kind === SyntaxKind.ArrayBindingPattern) {
+                    write("[");
+                    emitCommaList(bindingPattern.elements, emitBindingElement);
+                    write("]");
+                }
             }
+
+            function emitBindingElement(bindingElement: BindingElement) {
+                function getBindingElementTypeVisibilityError(symbolAccesibilityResult: SymbolAccessiblityResult): SymbolAccessibilityDiagnostic {
+                    let diagnosticMessage = getParameterDeclarationTypeVisibilityDiagnosticMessage(symbolAccesibilityResult);
+                    return diagnosticMessage !== undefined ? {
+                        diagnosticMessage,
+                        errorNode: bindingElement,
+                        typeName: bindingElement.name
+                    } : undefined;
+                }
+
+                if (bindingElement.propertyName) {
+                    // bindingElement has propertyName property in the following case:
+                    //      { y: [a,b,c] ...} -> bindingPattern will have a property called propertyName for "y"
+                    // We have to explicitly emit the propertyName before descending into its binding elements.
+                    // Example:
+                    //      original: function foo({y: [a,b,c]}) {}
+                    //      emit    : declare function foo({y: [a, b, c]}: { y: [any, any, any] }) void;
+                    writeTextOfNode(currentSourceFile, bindingElement.propertyName);
+                    write(": ");
+
+                    // If bindingElement has propertyName property, then its name must be another bindingPattern of SyntaxKind.ObjectBindingPattern
+                    emitBindingPattern(<BindingPattern>bindingElement.name);
+                }
+                else if (bindingElement.name) {
+                    if (isBindingPattern(bindingElement.name)) {
+                        // If it is a nested binding pattern, we will recursively descend into each element and emit each one separately.
+                        // In the case of rest element, we will omit rest element.
+                        // Example:
+                        //      original: function foo([a, [[b]], c] = [1,[["string"]], 3]) {}
+                        //      emit    : declare function foo([a, [[b]], c]: [number, [[string]], number]): void;
+                        //      original with rest: function foo([a ...c]) {}
+                        //      emit              : declare function foo([a, c]): void;
+                        emitBindingPattern(<BindingPattern>bindingElement.name);
+                    }
+                    else {
+                        // If the node is just an identifier, we will simply emit the text associated with the node's name
+                        // Example:
+                        //      original: function foo({y = 10, x}) {}
+                        //      emit    : declare function foo({y, x}: {number, any}): void;
+                        writeTextOfNode(currentSourceFile, bindingElement.name);
+                    }
+                }
+            } 
         }
 
         function emitNode(node: Node) {

tests/baselines/reference/declarationEmitDestructuringArrayPattern6.js

@@ -0,0 +1,65 @@
+//// [declarationEmitDestructuringArrayPattern6.ts]
+function f({x = 10, y: [a, b, c, d] = [1, 2, 3, 4]} = { x: 10, y: [2, 4, 6, 8] }) { }
+function g([a, b, c, d] = [1, 2, 3, 4]) { }
+function h([a, [b], [[c]], {x = 10, y: [a, b, c], z: {a1, b1}}]){ }
+function h1([a, [b], [[c]], {x = 10, y = [1, 2, 3], z: {a1, b1}}]){ }
+
+//// [declarationEmitDestructuringArrayPattern6.js]
+function f(_a) {
+    var _b = _a === void 0 ? {
+        x: 10,
+        y: [
+            2,
+            4,
+            6,
+            8
+        ]
+    } : _a, _c = _b.x, x = _c === void 0 ? 10 : _c, _d = _b.y, _e = _d === void 0 ? [
+        1,
+        2,
+        3,
+        4
+    ] : _d, a = _e[0], b = _e[1], c = _e[2], d = _e[3];
+}
+function g(_a) {
+    var _b = _a === void 0 ? [
+        1,
+        2,
+        3,
+        4
+    ] : _a, a = _b[0], b = _b[1], c = _b[2], d = _b[3];
+}
+function h(_a) {
+    var a = _a[0], b = _a[1][0], c = _a[2][0][0], _b = _a[3], _c = _b.x, x = _c === void 0 ? 10 : _c, _d = _b.y, a = _d[0], b = _d[1], c = _d[2], _e = _b.z, a1 = _e.a1, b1 = _e.b1;
+}
+function h1(_a) {
+    var a = _a[0], b = _a[1][0], c = _a[2][0][0], _b = _a[3], _c = _b.x, x = _c === void 0 ? 10 : _c, _d = _b.y, y = _d === void 0 ? [
+        1,
+        2,
+        3
+    ] : _d, _e = _b.z, a1 = _e.a1, b1 = _e.b1;
+}
+
+
+//// [declarationEmitDestructuringArrayPattern6.d.ts]
+declare function f({x, y: [a, b, c, d]}?: {
+    x: number;
+    y: [number, number, number, number];
+}): void;
+declare function g([a, b, c, d]?: [number, number, number, number]): void;
+declare function h([a, [b], [[c]], {x, y: [a, b, c], z: {a1, b1}}]: [any, [any], [[any]], {
+    x?: number;
+    y: [any, any, any];
+    z: {
+        a1: any;
+        b1: any;
+    };
+}]): void;
+declare function h1([a, [b], [[c]], {x, y, z: {a1, b1}}]: [any, [any], [[any]], {
+    x?: number;
+    y?: number[];
+    z: {
+        a1: any;
+        b1: any;
+    };
+}]): void;

tests/baselines/reference/declarationEmitDestructuringArrayPattern6.types

@@ -0,0 +1,49 @@
+=== tests/cases/compiler/declarationEmitDestructuringArrayPattern6.ts ===
+function f({x = 10, y: [a, b, c, d] = [1, 2, 3, 4]} = { x: 10, y: [2, 4, 6, 8] }) { }
+>f : ({x = 10, y: [a, b, c, d] = [1, 2, 3, 4]}?: { x: number; y: [number, number, number, number]; }) => void
+>x : number
+>y : unknown
+>a : number
+>b : number
+>c : number
+>d : number
+>[1, 2, 3, 4] : [number, number, number, number]
+>{ x: 10, y: [2, 4, 6, 8] } : { x: number; y: [number, number, number, number]; }
+>x : number
+>y : [number, number, number, number]
+>[2, 4, 6, 8] : [number, number, number, number]
+
+function g([a, b, c, d] = [1, 2, 3, 4]) { }
+>g : ([a, b, c, d]?: [number, number, number, number]) => void
+>a : number
+>b : number
+>c : number
+>d : number
+>[1, 2, 3, 4] : [number, number, number, number]
+
+function h([a, [b], [[c]], {x = 10, y: [a, b, c], z: {a1, b1}}]){ }
+>h : ([a, [b], [[c]], {x = 10, y: [a, b, c], z: {a1, b1}}]: [any, [any], [[any]], { x?: number; y: [any, any, any]; z: { a1: any; b1: any; }; }]) => void
+>a : any
+>b : any
+>c : any
+>x : number
+>y : unknown
+>a : any
+>b : any
+>c : any
+>z : unknown
+>a1 : any
+>b1 : any
+
+function h1([a, [b], [[c]], {x = 10, y = [1, 2, 3], z: {a1, b1}}]){ }
+>h1 : ([a, [b], [[c]], {x = 10, y = [1, 2, 3], z: {a1, b1}}]: [any, [any], [[any]], { x?: number; y?: number[]; z: { a1: any; b1: any; }; }]) => void
+>a : any
+>b : any
+>c : any
+>x : number
+>y : number[]
+>[1, 2, 3] : number[]
+>z : unknown
+>a1 : any
+>b1 : any
+

tests/baselines/reference/declarationEmitDestructuringArrayPattern7.js

@@ -0,0 +1,20 @@
+//// [declarationEmitDestructuringArrayPattern7.ts]
+function bar([x, z, ...w]) { }
+function foo([x, ...y] = [1, "string", true]) { }
+
+//// [declarationEmitDestructuringArrayPattern7.js]
+function bar(_a) {
+    var x = _a[0], z = _a[1], w = _a.slice(2);
+}
+function foo(_a) {
+    var _b = _a === void 0 ? [
+        1,
+        "string",
+        true
+    ] : _a, x = _b[0], y = _b.slice(1);
+}
+
+
+//// [declarationEmitDestructuringArrayPattern7.d.ts]
+declare function bar([x, z, w]: any[]): void;
+declare function foo([x, y]?: (string | number | boolean)[]): void;

tests/baselines/reference/declarationEmitDestructuringArrayPattern7.types

@@ -0,0 +1,13 @@
+=== tests/cases/compiler/declarationEmitDestructuringArrayPattern7.ts ===
+function bar([x, z, ...w]) { }
+>bar : ([x, z, ...w]: any[]) => void
+>x : any
+>z : any
+>w : any[]
+
+function foo([x, ...y] = [1, "string", true]) { }
+>foo : ([x, ...y]?: (string | number | boolean)[]) => void
+>x : string | number | boolean
+>y : (string | number | boolean)[]
+>[1, "string", true] : (string | number | boolean)[]
+

tests/baselines/reference/declarationEmitDestructuringOptionalBindingParametersInOverloads.js

@@ -26,7 +26,7 @@ function foo2() {
 
 //// [declarationEmitDestructuringOptionalBindingParametersInOverloads.d.ts]
 declare function foo([x, y, z]?: [string, number, boolean]): any;
-declare function foo2({ x, y, z }?: {
+declare function foo2({x, y, z}?: {
     x: string;
     y: number;
     z: boolean;

tests/baselines/reference/declarationEmitDestructuringParameterProperties.js

@@ -57,5 +57,5 @@ declare type ObjType1 = {
 };
 declare class C3 {
     x: number, y: string, z: boolean;
-    constructor({ x, y, z }: ObjType1);
+    constructor({x, y, z}: ObjType1);
 }

tests/baselines/reference/declarationEmitDestructuringWithOptionalBindingParameters.js

@@ -14,8 +14,8 @@ function foo1(_a) {
 
 
 //// [declarationEmitDestructuringWithOptionalBindingParameters.d.ts]
-declare function foo([x,y,z]?: [string, number, boolean]): void;
-declare function foo1({ x, y, z }?: {
+declare function foo([x, y, z]?: [string, number, boolean]): void;
+declare function foo1({x, y, z}?: {
     x: string;
     y: number;
     z: boolean;

tests/cases/compiler/declarationEmitDestructuringArrayPattern6.ts

@@ -0,0 +1,5 @@
+// @declaration: true
+function f({x = 10, y: [a, b, c, d] = [1, 2, 3, 4]} = { x: 10, y: [2, 4, 6, 8] }) { }
+function g([a, b, c, d] = [1, 2, 3, 4]) { }
+function h([a, [b], [[c]], {x = 10, y: [a, b, c], z: {a1, b1}}]){ }
+function h1([a, [b], [[c]], {x = 10, y = [1, 2, 3], z: {a1, b1}}]){ }

tests/cases/compiler/declarationEmitDestructuringArrayPattern7.ts

@@ -0,0 +1,3 @@
+// @declaration: true
+function bar([x, z, ...w]) { }
+function foo([x, ...y] = [1, "string", true]) { }