Merge pull request #2164 from Microsoft/for-ofES6

Support 'for...of' loops in ES6

Author: JsonFreeman

src/compiler/checker.ts

@@ -328,6 +328,13 @@ module ts {
         for_of_statements_are_only_available_when_targeting_ECMAScript_6_or_higher: { code: 2482, category: DiagnosticCategory.Error, key: "'for...of' statements are only available when targeting ECMAScript 6 or higher." },
         The_left_hand_side_of_a_for_of_statement_cannot_use_a_type_annotation: { code: 2483, category: DiagnosticCategory.Error, key: "The left-hand side of a 'for...of' statement cannot use a type annotation." },
         Export_declaration_conflicts_with_exported_declaration_of_0: { code: 2484, category: DiagnosticCategory.Error, key: "Export declaration conflicts with exported declaration of '{0}'" },
+        The_left_hand_side_of_a_for_of_statement_cannot_be_a_previously_defined_constant: { code: 2485, category: DiagnosticCategory.Error, key: "The left-hand side of a 'for...of' statement cannot be a previously defined constant." },
+        The_left_hand_side_of_a_for_in_statement_cannot_be_a_previously_defined_constant: { code: 2486, category: DiagnosticCategory.Error, key: "The left-hand side of a 'for...in' statement cannot be a previously defined constant." },
+        Invalid_left_hand_side_in_for_of_statement: { code: 2487, category: DiagnosticCategory.Error, key: "Invalid left-hand side in 'for...of' statement." },
+        The_right_hand_side_of_a_for_of_statement_must_have_a_Symbol_iterator_method_that_returns_an_iterator: { code: 2488, category: DiagnosticCategory.Error, key: "The right-hand side of a 'for...of' statement must have a '[Symbol.iterator]()' method that returns an iterator." },
+        The_iterator_returned_by_the_right_hand_side_of_a_for_of_statement_must_have_a_next_method: { code: 2489, category: DiagnosticCategory.Error, key: "The iterator returned by the right-hand side of a 'for...of' statement must have a 'next()' method." },
+        The_type_returned_by_the_next_method_of_an_iterator_must_have_a_value_property: { code: 2490, category: DiagnosticCategory.Error, key: "The type returned by the 'next()' method of an iterator must have a 'value' property." },
+        The_left_hand_side_of_a_for_in_statement_cannot_be_a_destructuring_pattern: { code: 2491, category: DiagnosticCategory.Error, key: "The left-hand side of a 'for...in' statement cannot be a destructuring pattern." },
         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}'." },
@@ -474,6 +481,5 @@ module ts {
         yield_expressions_are_not_currently_supported: { code: 9000, category: DiagnosticCategory.Error, key: "'yield' expressions are not currently supported." },
         Generators_are_not_currently_supported: { code: 9001, category: DiagnosticCategory.Error, key: "Generators are not currently supported." },
         The_arguments_object_cannot_be_referenced_in_an_arrow_function_Consider_using_a_standard_function_expression: { code: 9002, category: DiagnosticCategory.Error, key: "The 'arguments' object cannot be referenced in an arrow function. Consider using a standard function expression." },
-        for_of_statements_are_not_currently_supported: { code: 9003, category: DiagnosticCategory.Error, key: "'for...of' statements are not currently supported." },
     };
 }

src/compiler/diagnosticInformationMap.generated.ts

@@ -1304,6 +1304,34 @@
         "category": "Error",
         "code": 2484
     },
+    "The left-hand side of a 'for...of' statement cannot be a previously defined constant.": {
+        "category": "Error",
+        "code": 2485
+    },
+    "The left-hand side of a 'for...in' statement cannot be a previously defined constant.": {
+        "category": "Error",
+        "code": 2486
+    },
+    "Invalid left-hand side in 'for...of' statement.": {
+        "category": "Error",
+        "code": 2487
+    },
+    "The right-hand side of a 'for...of' statement must have a '[Symbol.iterator]()' method that returns an iterator.": {
+        "category": "Error",
+        "code": 2488
+    },
+    "The iterator returned by the right-hand side of a 'for...of' statement must have a 'next()' method.": {
+        "category": "Error",
+        "code": 2489
+    },
+    "The type returned by the 'next()' method of an iterator must have a 'value' property.": {
+        "category": "Error",
+        "code": 2490
+    },
+    "The left-hand side of a 'for...in' statement cannot be a destructuring pattern.": {
+        "category": "Error",
+        "code": 2491
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
@@ -1889,9 +1917,5 @@
     "The 'arguments' object cannot be referenced in an arrow function. Consider using a standard function expression.": {
         "category": "Error",
         "code": 9002
-    },
-    "'for...of' statements are not currently supported.": {
-        "category": "Error",
-        "code": 9003
     }
 }

src/compiler/diagnosticMessages.json

@@ -683,7 +683,7 @@ module ts {
     }
 
     export function isBindingPattern(node: Node) {
-        return node.kind === SyntaxKind.ArrayBindingPattern || node.kind === SyntaxKind.ObjectBindingPattern;
+        return !!node && (node.kind === SyntaxKind.ArrayBindingPattern || node.kind === SyntaxKind.ObjectBindingPattern);
     }
 
     export function isInAmbientContext(node: Node): boolean {

src/compiler/utilities.ts

@@ -1,9 +1,9 @@
-tests/cases/compiler/downlevelLetConst16.ts(189,5): error TS9003: 'for...of' statements are not currently supported.
-tests/cases/compiler/downlevelLetConst16.ts(196,5): error TS9003: 'for...of' statements are not currently supported.
-tests/cases/compiler/downlevelLetConst16.ts(203,5): error TS9003: 'for...of' statements are not currently supported.
-tests/cases/compiler/downlevelLetConst16.ts(210,5): error TS9003: 'for...of' statements are not currently supported.
-tests/cases/compiler/downlevelLetConst16.ts(217,5): error TS9003: 'for...of' statements are not currently supported.
-tests/cases/compiler/downlevelLetConst16.ts(224,5): error TS9003: 'for...of' statements are not currently supported.
+tests/cases/compiler/downlevelLetConst16.ts(189,5): error TS2482: 'for...of' statements are only available when targeting ECMAScript 6 or higher.
+tests/cases/compiler/downlevelLetConst16.ts(196,5): error TS2482: 'for...of' statements are only available when targeting ECMAScript 6 or higher.
+tests/cases/compiler/downlevelLetConst16.ts(203,5): error TS2482: 'for...of' statements are only available when targeting ECMAScript 6 or higher.
+tests/cases/compiler/downlevelLetConst16.ts(210,5): error TS2482: 'for...of' statements are only available when targeting ECMAScript 6 or higher.
+tests/cases/compiler/downlevelLetConst16.ts(217,5): error TS2482: 'for...of' statements are only available when targeting ECMAScript 6 or higher.
+tests/cases/compiler/downlevelLetConst16.ts(224,5): error TS2482: 'for...of' statements are only available when targeting ECMAScript 6 or higher.
 
 
 ==== tests/cases/compiler/downlevelLetConst16.ts (6 errors) ====
@@ -197,7 +197,7 @@ tests/cases/compiler/downlevelLetConst16.ts(224,5): error TS9003: 'for...of' sta
     function foo7() {
         for (let x of []) {
         ~~~
-!!! error TS9003: 'for...of' statements are not currently supported.
+!!! error TS2482: 'for...of' statements are only available when targeting ECMAScript 6 or higher.
             use(x);
         }
         use(x);
@@ -206,7 +206,7 @@ tests/cases/compiler/downlevelLetConst16.ts(224,5): error TS9003: 'for...of' sta
     function foo8() {
         for (let [x] of []) {
         ~~~
-!!! error TS9003: 'for...of' statements are not currently supported.
+!!! error TS2482: 'for...of' statements are only available when targeting ECMAScript 6 or higher.
             use(x);
         }
         use(x);
@@ -215,7 +215,7 @@ tests/cases/compiler/downlevelLetConst16.ts(224,5): error TS9003: 'for...of' sta
     function foo9() {
         for (let {a: x} of []) {
         ~~~
-!!! error TS9003: 'for...of' statements are not currently supported.
+!!! error TS2482: 'for...of' statements are only available when targeting ECMAScript 6 or higher.
             use(x);
         }
         use(x);
@@ -224,7 +224,7 @@ tests/cases/compiler/downlevelLetConst16.ts(224,5): error TS9003: 'for...of' sta
     function foo10() {
         for (const x of []) {
         ~~~
-!!! error TS9003: 'for...of' statements are not currently supported.
+!!! error TS2482: 'for...of' statements are only available when targeting ECMAScript 6 or higher.
             use(x);
         }
         use(x);
@@ -233,7 +233,7 @@ tests/cases/compiler/downlevelLetConst16.ts(224,5): error TS9003: 'for...of' sta
     function foo11() {
         for (const [x] of []) {
         ~~~
-!!! error TS9003: 'for...of' statements are not currently supported.
+!!! error TS2482: 'for...of' statements are only available when targeting ECMAScript 6 or higher.
             use(x);
         }
         use(x);
@@ -242,7 +242,7 @@ tests/cases/compiler/downlevelLetConst16.ts(224,5): error TS9003: 'for...of' sta
     function foo12() {
         for (const {a: x} of []) {
         ~~~
-!!! error TS9003: 'for...of' statements are not currently supported.
+!!! error TS2482: 'for...of' statements are only available when targeting ECMAScript 6 or higher.
             use(x);
         }
         use(x);

tests/baselines/reference/downlevelLetConst16.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/downlevelLetConst17.ts(66,1): error TS9003: 'for...of' statements are not currently supported.
+tests/cases/compiler/downlevelLetConst17.ts(66,1): error TS2482: 'for...of' statements are only available when targeting ECMAScript 6 or higher.
 
 
 ==== tests/cases/compiler/downlevelLetConst17.ts (1 errors) ====
@@ -69,6 +69,6 @@ tests/cases/compiler/downlevelLetConst17.ts(66,1): error TS9003: 'for...of' stat
     // TODO: update once for-of statements are supported downlevel
     for (const x of []) {
     ~~~
-!!! error TS9003: 'for...of' statements are not currently supported.
+!!! error TS2482: 'for...of' statements are only available when targeting ECMAScript 6 or higher.
         use(x);
     }

tests/baselines/reference/downlevelLetConst17.errors.txt

@@ -0,0 +1,7 @@
+tests/cases/conformance/statements/for-inStatements/for-inStatementsDestructuring.ts(1,10): error TS2491: The left-hand side of a 'for...in' statement cannot be a destructuring pattern.
+
+
+==== tests/cases/conformance/statements/for-inStatements/for-inStatementsDestructuring.ts (1 errors) ====
+    for (var [a, b] in []) {}
+             ~~~~~~
+!!! error TS2491: The left-hand side of a 'for...in' statement cannot be a destructuring pattern.

tests/baselines/reference/for-inStatementsDestructuring.errors.txt

@@ -0,0 +1,5 @@
+//// [for-inStatementsDestructuring.ts]
+for (var [a, b] in []) {}
+
+//// [for-inStatementsDestructuring.js]
+for (var _a = void 0, a = _a[0], b = _a[1] in []) { }

tests/baselines/reference/for-inStatementsDestructuring.js

@@ -0,0 +1,7 @@
+tests/cases/conformance/statements/for-inStatements/for-inStatementsDestructuring2.ts(1,10): error TS2491: The left-hand side of a 'for...in' statement cannot be a destructuring pattern.
+
+
+==== tests/cases/conformance/statements/for-inStatements/for-inStatementsDestructuring2.ts (1 errors) ====
+    for (var {a, b} in []) {}
+             ~~~~~~
+!!! error TS2491: The left-hand side of a 'for...in' statement cannot be a destructuring pattern.

tests/baselines/reference/for-inStatementsDestructuring2.errors.txt

@@ -0,0 +1,5 @@
+//// [for-inStatementsDestructuring2.ts]
+for (var {a, b} in []) {}
+
+//// [for-inStatementsDestructuring2.js]
+for (var _a = void 0, a = _a.a, b = _a.b in []) { }

tests/baselines/reference/for-inStatementsDestructuring2.js

@@ -0,0 +1,8 @@
+tests/cases/conformance/statements/for-inStatements/for-inStatementsDestructuring3.ts(2,6): error TS2491: The left-hand side of a 'for...in' statement cannot be a destructuring pattern.
+
+
+==== tests/cases/conformance/statements/for-inStatements/for-inStatementsDestructuring3.ts (1 errors) ====
+    var a, b;
+    for ([a, b] in []) { }
+         ~~~~~~
+!!! error TS2491: The left-hand side of a 'for...in' statement cannot be a destructuring pattern.

tests/baselines/reference/for-inStatementsDestructuring3.errors.txt

@@ -0,0 +1,7 @@
+//// [for-inStatementsDestructuring3.ts]
+var a, b;
+for ([a, b] in []) { }
+
+//// [for-inStatementsDestructuring3.js]
+var a, b;
+for ([a, b] in []) { }

tests/baselines/reference/for-inStatementsDestructuring3.js

@@ -0,0 +1,8 @@
+tests/cases/conformance/statements/for-inStatements/for-inStatementsDestructuring4.ts(2,6): error TS2491: The left-hand side of a 'for...in' statement cannot be a destructuring pattern.
+
+
+==== tests/cases/conformance/statements/for-inStatements/for-inStatementsDestructuring4.ts (1 errors) ====
+    var a, b;
+    for ({a, b} in []) { }
+         ~~~~~~
+!!! error TS2491: The left-hand side of a 'for...in' statement cannot be a destructuring pattern.

tests/baselines/reference/for-inStatementsDestructuring4.errors.txt

@@ -0,0 +1,7 @@
+//// [for-inStatementsDestructuring4.ts]
+var a, b;
+for ({a, b} in []) { }
+
+//// [for-inStatementsDestructuring4.js]
+var a, b;
+for ({ a: a, b: b } in []) { }

tests/baselines/reference/for-inStatementsDestructuring4.js

@@ -0,0 +1,7 @@
+//// [for-of1.ts]
+var v;
+for (v of []) { }
+
+//// [for-of1.js]
+var v;
+for (v of []) { }

tests/baselines/reference/for-of1.js

@@ -0,0 +1,8 @@
+=== tests/cases/conformance/es6/for-ofStatements/for-of1.ts ===
+var v;
+>v : any
+
+for (v of []) { }
+>v : any
+>[] : undefined[]
+

tests/baselines/reference/for-of1.types

@@ -0,0 +1,8 @@
+tests/cases/conformance/es6/for-ofStatements/for-of10.ts(2,6): error TS2322: Type 'number' is not assignable to type 'string'.
+
+
+==== tests/cases/conformance/es6/for-ofStatements/for-of10.ts (1 errors) ====
+    var v: string;
+    for (v of [0]) { }
+         ~
+!!! error TS2322: Type 'number' is not assignable to type 'string'.

tests/baselines/reference/for-of10.errors.txt

@@ -0,0 +1,7 @@
+//// [for-of10.ts]
+var v: string;
+for (v of [0]) { }
+
+//// [for-of10.js]
+var v;
+for (v of [0]) { }

tests/baselines/reference/for-of10.js

@@ -0,0 +1,10 @@
+tests/cases/conformance/es6/for-ofStatements/for-of11.ts(2,6): error TS2322: Type 'string | number' is not assignable to type 'string'.
+  Type 'number' is not assignable to type 'string'.
+
+
+==== tests/cases/conformance/es6/for-ofStatements/for-of11.ts (1 errors) ====
+    var v: string;
+    for (v of [0, ""]) { }
+         ~
+!!! error TS2322: Type 'string | number' is not assignable to type 'string'.
+!!! error TS2322:   Type 'number' is not assignable to type 'string'.

tests/baselines/reference/for-of11.errors.txt

@@ -0,0 +1,7 @@
+//// [for-of11.ts]
+var v: string;
+for (v of [0, ""]) { }
+
+//// [for-of11.js]
+var v;
+for (v of [0, ""]) { }

tests/baselines/reference/for-of11.js

@@ -0,0 +1,10 @@
+tests/cases/conformance/es6/for-ofStatements/for-of12.ts(2,6): error TS2322: Type 'string | number' is not assignable to type 'string'.
+  Type 'number' is not assignable to type 'string'.
+
+
+==== tests/cases/conformance/es6/for-ofStatements/for-of12.ts (1 errors) ====
+    var v: string;
+    for (v of [0, ""].values()) { }
+         ~
+!!! error TS2322: Type 'string | number' is not assignable to type 'string'.
+!!! error TS2322:   Type 'number' is not assignable to type 'string'.

tests/baselines/reference/for-of12.errors.txt

@@ -0,0 +1,7 @@
+//// [for-of12.ts]
+var v: string;
+for (v of [0, ""].values()) { }
+
+//// [for-of12.js]
+var v;
+for (v of [0, ""].values()) { }

tests/baselines/reference/for-of12.js

@@ -0,0 +1,7 @@
+//// [for-of13.ts]
+var v: string;
+for (v of [""].values()) { }
+
+//// [for-of13.js]
+var v;
+for (v of [""].values()) { }

tests/baselines/reference/for-of13.js

@@ -0,0 +1,11 @@
+=== tests/cases/conformance/es6/for-ofStatements/for-of13.ts ===
+var v: string;
+>v : string
+
+for (v of [""].values()) { }
+>v : string
+>[""].values() : IterableIterator<string>
+>[""].values : () => IterableIterator<string>
+>[""] : string[]
+>values : () => IterableIterator<string>
+

tests/baselines/reference/for-of13.types

@@ -0,0 +1,14 @@
+tests/cases/conformance/es6/for-ofStatements/for-of14.ts(2,11): error TS2488: The right-hand side of a 'for...of' statement must have a '[Symbol.iterator]()' method that returns an iterator.
+
+
+==== tests/cases/conformance/es6/for-ofStatements/for-of14.ts (1 errors) ====
+    var v: string;
+    for (v of new StringIterator) { } // Should fail because the iterator is not iterable
+              ~~~~~~~~~~~~~~~~~~
+!!! error TS2488: The right-hand side of a 'for...of' statement must have a '[Symbol.iterator]()' method that returns an iterator.
+    
+    class StringIterator {
+        next() {
+            return "";
+        }
+    }

tests/baselines/reference/for-of14.errors.txt

@@ -0,0 +1,21 @@
+//// [for-of14.ts]
+var v: string;
+for (v of new StringIterator) { } // Should fail because the iterator is not iterable
+
+class StringIterator {
+    next() {
+        return "";
+    }
+}
+
+//// [for-of14.js]
+var v;
+for (v of new StringIterator) { } // Should fail because the iterator is not iterable
+var StringIterator = (function () {
+    function StringIterator() {
+    }
+    StringIterator.prototype.next = function () {
+        return "";
+    };
+    return StringIterator;
+})();

tests/baselines/reference/for-of14.js

@@ -0,0 +1,17 @@
+tests/cases/conformance/es6/for-ofStatements/for-of15.ts(2,11): error TS2490: The type returned by the 'next()' method of an iterator must have a 'value' property.
+
+
+==== tests/cases/conformance/es6/for-ofStatements/for-of15.ts (1 errors) ====
+    var v: string;
+    for (v of new StringIterator) { } // Should fail
+              ~~~~~~~~~~~~~~~~~~
+!!! error TS2490: The type returned by the 'next()' method of an iterator must have a 'value' property.
+    
+    class StringIterator {
+        next() {
+            return "";
+        }
+        [Symbol.iterator]() {
+            return this;
+        }
+    }