Merge pull request #1931 from Microsoft/spreadCall

Support spread operator in call expressions

Author: ahejlsberg

src/compiler/checker.ts

@@ -303,6 +303,7 @@ module ts {
         this_cannot_be_referenced_in_a_computed_property_name: { code: 2465, category: DiagnosticCategory.Error, key: "'this' cannot be referenced in a computed property name." },
         super_cannot_be_referenced_in_a_computed_property_name: { code: 2466, category: DiagnosticCategory.Error, key: "'super' cannot be referenced in a computed property name." },
         A_computed_property_name_cannot_reference_a_type_parameter_from_its_containing_type: { code: 2466, category: DiagnosticCategory.Error, key: "A computed property name cannot reference a type parameter from its containing type." },
+        Spread_operator_in_new_expressions_is_only_available_when_targeting_ECMAScript_6_and_higher: { code: 2468, category: DiagnosticCategory.Error, key: "Spread operator in 'new' expressions is only available when targeting ECMAScript 6 and higher." },
         Import_declaration_0_is_using_private_name_1: { code: 4000, category: DiagnosticCategory.Error, key: "Import declaration '{0}' is using private name '{1}'." },
         Type_parameter_0_of_exported_class_has_or_is_using_private_name_1: { code: 4002, category: DiagnosticCategory.Error, key: "Type parameter '{0}' of exported class has or is using private name '{1}'." },
         Type_parameter_0_of_exported_interface_has_or_is_using_private_name_1: { code: 4004, category: DiagnosticCategory.Error, key: "Type parameter '{0}' of exported interface has or is using private name '{1}'." },

src/compiler/diagnosticInformationMap.generated.ts

@@ -1204,6 +1204,10 @@
         "category": "Error",
         "code": 2466
     },
+    "Spread operator in 'new' expressions is only available when targeting ECMAScript 6 and higher.": {
+        "category": "Error",
+        "code": 2468
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",

src/compiler/diagnosticMessages.json

@@ -1994,7 +1994,7 @@ module ts {
                         break;
                     }
                     // _a .. _h, _j ... _z, _0, _1, ...
-                    name = "_" + (tempCount < 25 ? String.fromCharCode(tempCount + (tempCount < 8 ? 0: 1) + CharacterCodes.a) : tempCount - 25);
+                    name = "_" + (tempCount < 25 ? String.fromCharCode(tempCount + (tempCount < 8 ? 0 : 1) + CharacterCodes.a) : tempCount - 25);
                     tempCount++;
                 }
                 var result = <Identifier>createNode(SyntaxKind.Identifier);
@@ -2423,22 +2423,10 @@ module ts {
                 return true;
             }
 
-            function emitArrayLiteral(node: ArrayLiteralExpression) {
-                var elements = node.elements;
-                var length = elements.length;
-                if (length === 0) {
-                    write("[]");
-                    return;
-                }
-                if (languageVersion >= ScriptTarget.ES6) {
-                    write("[");
-                    emitList(elements, 0, elements.length, /*multiLine*/(node.flags & NodeFlags.MultiLine) !== 0,
-                        /*trailingComma*/ elements.hasTrailingComma);
-                    write("]");
-                    return;
-                }
+            function emitListWithSpread(elements: Expression[], multiLine: boolean, trailingComma: boolean) {
                 var pos = 0;
                 var group = 0;
+                var length = elements.length;
                 while (pos < length) {
                     // Emit using the pattern <group0>.concat(<group1>, <group2>, ...)
                     if (group === 1) {
@@ -2459,8 +2447,7 @@ module ts {
                             i++;
                         }
                         write("[");
-                        emitList(elements, pos, i - pos, /*multiLine*/ (node.flags & NodeFlags.MultiLine) !== 0,
-                            /*trailingComma*/ elements.hasTrailingComma);
+                        emitList(elements, pos, i - pos, multiLine, trailingComma && i === length);
                         write("]");
                         pos = i;
                     }
@@ -2471,6 +2458,23 @@ module ts {
                 }
             }
 
+            function emitArrayLiteral(node: ArrayLiteralExpression) {
+                var elements = node.elements;
+                if (elements.length === 0) {
+                    write("[]");
+                }
+                else if (languageVersion >= ScriptTarget.ES6) {
+                    write("[");
+                    emitList(elements, 0, elements.length, /*multiLine*/ (node.flags & NodeFlags.MultiLine) !== 0,
+                        /*trailingComma*/ elements.hasTrailingComma);
+                    write("]");
+                }
+                else {
+                    emitListWithSpread(elements, /*multiLine*/ (node.flags & NodeFlags.MultiLine) !== 0,
+                        /*trailingComma*/ elements.hasTrailingComma);
+                }
+            }
+
             function emitObjectLiteral(node: ObjectLiteralExpression) {
                 write("{");
                 var properties = node.properties;
@@ -2565,7 +2569,80 @@ module ts {
                 write("]");
             }
 
+            function hasSpreadElement(elements: Expression[]) {
+                return forEach(elements, e => e.kind === SyntaxKind.SpreadElementExpression);
+            }
+
+            function skipParentheses(node: Expression): Expression {
+                while (node.kind === SyntaxKind.ParenthesizedExpression || node.kind === SyntaxKind.TypeAssertionExpression) {
+                    node = (<ParenthesizedExpression | TypeAssertion>node).expression;
+                }
+                return node;
+            }
+
+            function emitCallTarget(node: Expression): Expression {
+                if (node.kind === SyntaxKind.Identifier || node.kind === SyntaxKind.ThisKeyword || node.kind === SyntaxKind.SuperKeyword) {
+                    emit(node);
+                    return node;
+                }
+                var temp = createTempVariable(node);
+                recordTempDeclaration(temp);
+                write("(");
+                emit(temp);
+                write(" = ");
+                emit(node);
+                write(")");
+                return temp;
+            }
+
+            function emitCallWithSpread(node: CallExpression) {
+                var target: Expression;
+                var expr = skipParentheses(node.expression);
+                if (expr.kind === SyntaxKind.PropertyAccessExpression) {
+                    // Target will be emitted as "this" argument
+                    target = emitCallTarget((<PropertyAccessExpression>expr).expression);
+                    write(".");
+                    emit((<PropertyAccessExpression>expr).name);
+                }
+                else if (expr.kind === SyntaxKind.ElementAccessExpression) {
+                    // Target will be emitted as "this" argument
+                    target = emitCallTarget((<PropertyAccessExpression>expr).expression);
+                    write("[");
+                    emit((<ElementAccessExpression>expr).argumentExpression);
+                    write("]");
+                }
+                else if (expr.kind === SyntaxKind.SuperKeyword) {
+                    target = expr;
+                    write("_super");
+                }
+                else {
+                    emit(node.expression);
+                }
+                write(".apply(");
+                if (target) {
+                    if (target.kind === SyntaxKind.SuperKeyword) {
+                        // Calls of form super(...) and super.foo(...)
+                        emitThis(target);
+                    }
+                    else {
+                        // Calls of form obj.foo(...)
+                        emit(target);
+                    }
+                }
+                else {
+                    // Calls of form foo(...)
+                    write("void 0");
+                }
+                write(", ");
+                emitListWithSpread(node.arguments, /*multiLine*/ false, /*trailingComma*/ false);
+                write(")");
+            }
+
             function emitCallExpression(node: CallExpression) {
+                if (languageVersion < ScriptTarget.ES6 && hasSpreadElement(node.arguments)) {
+                    emitCallWithSpread(node);
+                    return;
+                }
                 var superCall = false;
                 if (node.expression.kind === SyntaxKind.SuperKeyword) {
                     write("_super");

src/compiler/emitter.ts

@@ -1516,7 +1516,6 @@ module ts {
                 case ParsingContext.TypeParameters:
                     return isIdentifier();
                 case ParsingContext.ArgumentExpressions:
-                    return token === SyntaxKind.CommaToken || isStartOfExpression();
                 case ParsingContext.ArrayLiteralMembers:
                     return token === SyntaxKind.CommaToken || token === SyntaxKind.DotDotDotToken || isStartOfExpression();
                 case ParsingContext.Parameters:
@@ -3605,32 +3604,28 @@ module ts {
             return finishNode(node);
         }
 
-        function parseAssignmentExpressionOrOmittedExpression(): Expression {
-            return token === SyntaxKind.CommaToken
-                ? <Expression>createNode(SyntaxKind.OmittedExpression)
-                : parseAssignmentExpressionOrHigher();
-        }
-
         function parseSpreadElement(): Expression {
             var node = <SpreadElementExpression>createNode(SyntaxKind.SpreadElementExpression);
             parseExpected(SyntaxKind.DotDotDotToken);
             node.expression = parseAssignmentExpressionOrHigher();
             return finishNode(node);
         }
 
-        function parseArrayLiteralElement(): Expression {
-            return token === SyntaxKind.DotDotDotToken ? parseSpreadElement() : parseAssignmentExpressionOrOmittedExpression();
+        function parseArgumentOrArrayLiteralElement(): Expression {
+            return token === SyntaxKind.DotDotDotToken ? parseSpreadElement() :
+                token === SyntaxKind.CommaToken ? <Expression>createNode(SyntaxKind.OmittedExpression) :
+                parseAssignmentExpressionOrHigher();
         }
 
         function parseArgumentExpression(): Expression {
-            return allowInAnd(parseAssignmentExpressionOrOmittedExpression);
+            return allowInAnd(parseArgumentOrArrayLiteralElement);
         }
 
         function parseArrayLiteralExpression(): ArrayLiteralExpression {
             var node = <ArrayLiteralExpression>createNode(SyntaxKind.ArrayLiteralExpression);
             parseExpected(SyntaxKind.OpenBracketToken);
             if (scanner.hasPrecedingLineBreak()) node.flags |= NodeFlags.MultiLine;
-            node.elements = parseDelimitedList(ParsingContext.ArrayLiteralMembers, parseArrayLiteralElement);
+            node.elements = parseDelimitedList(ParsingContext.ArrayLiteralMembers, parseArgumentOrArrayLiteralElement);
             parseExpected(SyntaxKind.CloseBracketToken);
             return finishNode(node);
         }

src/compiler/parser.ts

@@ -0,0 +1,59 @@
+tests/cases/conformance/expressions/functionCalls/callWithSpread.ts(52,21): error TS2468: Spread operator in 'new' expressions is only available when targeting ECMAScript 6 and higher.
+
+
+==== tests/cases/conformance/expressions/functionCalls/callWithSpread.ts (1 errors) ====
+    interface X {
+        foo(x: number, y: number, ...z: string[]);
+    }
+    
+    function foo(x: number, y: number, ...z: string[]) {
+    }
+    
+    var a: string[];
+    var z: number[];
+    var obj: X;
+    var xa: X[];
+    
+    foo(1, 2, "abc");
+    foo(1, 2, ...a);
+    foo(1, 2, ...a, "abc");
+    
+    obj.foo(1, 2, "abc");
+    obj.foo(1, 2, ...a);
+    obj.foo(1, 2, ...a, "abc");
+    
+    (obj.foo)(1, 2, "abc");
+    (obj.foo)(1, 2, ...a);
+    (obj.foo)(1, 2, ...a, "abc");
+    
+    xa[1].foo(1, 2, "abc");
+    xa[1].foo(1, 2, ...a);
+    xa[1].foo(1, 2, ...a, "abc");
+    
+    (<Function>xa[1].foo)(...[1, 2, "abc"]);
+    
+    class C {
+        constructor(x: number, y: number, ...z: string[]) {
+            this.foo(x, y);
+            this.foo(x, y, ...z);
+        }
+        foo(x: number, y: number, ...z: string[]) {
+        }
+    }
+    
+    class D extends C {
+        constructor() {
+            super(1, 2);
+            super(1, 2, ...a);
+        }
+        foo() {
+            super.foo(1, 2);
+            super.foo(1, 2, ...a);
+        }
+    }
+    
+    // Only supported in when target is ES6
+    var c = new C(1, 2, ...a);
+                        ~~~~
+!!! error TS2468: Spread operator in 'new' expressions is only available when targeting ECMAScript 6 and higher.
+    

tests/baselines/reference/callWithSpread.errors.txt

@@ -0,0 +1,117 @@
+//// [callWithSpread.ts]
+interface X {
+    foo(x: number, y: number, ...z: string[]);
+}
+
+function foo(x: number, y: number, ...z: string[]) {
+}
+
+var a: string[];
+var z: number[];
+var obj: X;
+var xa: X[];
+
+foo(1, 2, "abc");
+foo(1, 2, ...a);
+foo(1, 2, ...a, "abc");
+
+obj.foo(1, 2, "abc");
+obj.foo(1, 2, ...a);
+obj.foo(1, 2, ...a, "abc");
+
+(obj.foo)(1, 2, "abc");
+(obj.foo)(1, 2, ...a);
+(obj.foo)(1, 2, ...a, "abc");
+
+xa[1].foo(1, 2, "abc");
+xa[1].foo(1, 2, ...a);
+xa[1].foo(1, 2, ...a, "abc");
+
+(<Function>xa[1].foo)(...[1, 2, "abc"]);
+
+class C {
+    constructor(x: number, y: number, ...z: string[]) {
+        this.foo(x, y);
+        this.foo(x, y, ...z);
+    }
+    foo(x: number, y: number, ...z: string[]) {
+    }
+}
+
+class D extends C {
+    constructor() {
+        super(1, 2);
+        super(1, 2, ...a);
+    }
+    foo() {
+        super.foo(1, 2);
+        super.foo(1, 2, ...a);
+    }
+}
+
+// Only supported in when target is ES6
+var c = new C(1, 2, ...a);
+
+
+//// [callWithSpread.js]
+var __extends = this.__extends || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    __.prototype = b.prototype;
+    d.prototype = new __();
+};
+function foo(x, y) {
+    var z = [];
+    for (var _i = 2; _i < arguments.length; _i++) {
+        z[_i - 2] = arguments[_i];
+    }
+}
+var a;
+var z;
+var obj;
+var xa;
+foo(1, 2, "abc");
+foo.apply(void 0, [1, 2].concat(a));
+foo.apply(void 0, [1, 2].concat(a, ["abc"]));
+obj.foo(1, 2, "abc");
+obj.foo.apply(obj, [1, 2].concat(a));
+obj.foo.apply(obj, [1, 2].concat(a, ["abc"]));
+(obj.foo)(1, 2, "abc");
+obj.foo.apply(obj, [1, 2].concat(a));
+obj.foo.apply(obj, [1, 2].concat(a, ["abc"]));
+xa[1].foo(1, 2, "abc");
+(_a = xa[1]).foo.apply(_a, [1, 2].concat(a));
+(_b = xa[1]).foo.apply(_b, [1, 2].concat(a, ["abc"]));
+(_c = xa[1]).foo.apply(_c, [1, 2, "abc"]);
+var C = (function () {
+    function C(x, y) {
+        var z = [];
+        for (var _i = 2; _i < arguments.length; _i++) {
+            z[_i - 2] = arguments[_i];
+        }
+        this.foo(x, y);
+        this.foo.apply(this, [x, y].concat(z));
+    }
+    C.prototype.foo = function (x, y) {
+        var z = [];
+        for (var _i = 2; _i < arguments.length; _i++) {
+            z[_i - 2] = arguments[_i];
+        }
+    };
+    return C;
+})();
+var D = (function (_super) {
+    __extends(D, _super);
+    function D() {
+        _super.call(this, 1, 2);
+        _super.apply(this, [1, 2].concat(a));
+    }
+    D.prototype.foo = function () {
+        _super.prototype.foo.call(this, 1, 2);
+        _super.prototype.foo.apply(this, [1, 2].concat(a));
+    };
+    return D;
+})(C);
+// Only supported in when target is ES6
+var c = new C(1, 2, ...a);
+var _a, _b, _c;