Fix getIteratedType to work with 'any' at all levels

src/compiler/checker.ts

@@ -8846,7 +8846,7 @@ module ts {
         function getIteratedType(iterable: Type, expressionForError: Expression): Type {
             Debug.assert(languageVersion >= ScriptTarget.ES6);
             if (allConstituentTypesHaveKind(iterable, TypeFlags.Any)) {
-                return anyType;
+                return iterable; // any or unknown
             }
 
             // We want to treat type as an iterable, and get the type it is an iterable of. The iterable
@@ -8867,6 +8867,10 @@ module ts {
             // T is the type we are after. At every level that involves analyzing return types
             // of signatures, we union the return types of all the signatures.
             var iteratorFunction = getTypeOfPropertyOfType(iterable, getPropertyNameForKnownSymbolName("iterator"));
+            if (iteratorFunction && allConstituentTypesHaveKind(iteratorFunction, TypeFlags.Any)) {
+                return iteratorFunction; // any or unknown
+            }
+            
             var iteratorFunctionSignatures = iteratorFunction ? getSignaturesOfType(iteratorFunction, SignatureKind.Call) : emptyArray;
             if (iteratorFunctionSignatures.length === 0) {
                 error(expressionForError, Diagnostics.The_right_hand_side_of_a_for_of_statement_must_have_a_Symbol_iterator_method_that_returns_an_iterator);
@@ -8874,8 +8878,15 @@ module ts {
             }
 
             var iterator = getUnionType(map(iteratorFunctionSignatures, getReturnTypeOfSignature));
+            if (allConstituentTypesHaveKind(iterator, TypeFlags.Any)) {
+                return iterator; // any or unknown
+            }
 
             var iteratorNextFunction = getTypeOfPropertyOfType(iterator, "next");
+            if (iteratorNextFunction && allConstituentTypesHaveKind(iteratorNextFunction, TypeFlags.Any)) {
+                return iteratorNextFunction; // any or unknown
+            }
+            
             var iteratorNextFunctionSignatures = iteratorNextFunction ? getSignaturesOfType(iteratorNextFunction, SignatureKind.Call) : emptyArray;
             if (iteratorNextFunctionSignatures.length === 0) {
                 error(expressionForError, Diagnostics.The_iterator_returned_by_the_right_hand_side_of_a_for_of_statement_must_have_a_next_method);
@@ -8883,6 +8894,9 @@ module ts {
             }
 
             var iteratorNextResult = getUnionType(map(iteratorNextFunctionSignatures, getReturnTypeOfSignature));
+            if (allConstituentTypesHaveKind(iteratorNextResult, TypeFlags.Any)) {
+                return iteratorNextResult; // any or unknown
+            }
 
             var iteratorNextValue = getTypeOfPropertyOfType(iteratorNextResult, "value");
             if (!iteratorNextValue) {

tests/baselines/reference/for-of24.js

@@ -0,0 +1,8 @@
+//// [for-of24.ts]
+var x: any;
+for (var v of x) { }
+
+
+//// [for-of24.js]
+var x;
+for (var v of x) { }

tests/baselines/reference/for-of24.types

@@ -0,0 +1,8 @@
+=== tests/cases/conformance/es6/for-ofStatements/for-of24.ts ===
+var x: any;
+>x : any
+
+for (var v of x) { }
+>v : any
+>x : any
+

tests/baselines/reference/for-of25.js

@@ -0,0 +1,21 @@
+//// [for-of25.ts]
+var x: any;
+for (var v of new StringIterator) { }
+
+class StringIterator {
+    [Symbol.iterator]() {
+        return x;
+    }
+}
+
+//// [for-of25.js]
+var x;
+for (var v of new StringIterator) { }
+var StringIterator = (function () {
+    function StringIterator() {
+    }
+    StringIterator.prototype[Symbol.iterator] = function () {
+        return x;
+    };
+    return StringIterator;
+})();

tests/baselines/reference/for-of25.types

@@ -0,0 +1,21 @@
+=== tests/cases/conformance/es6/for-ofStatements/for-of25.ts ===
+var x: any;
+>x : any
+
+for (var v of new StringIterator) { }
+>v : any
+>new StringIterator : StringIterator
+>StringIterator : typeof StringIterator
+
+class StringIterator {
+>StringIterator : StringIterator
+
+    [Symbol.iterator]() {
+>Symbol.iterator : symbol
+>Symbol : SymbolConstructor
+>iterator : symbol
+
+        return x;
+>x : any
+    }
+}

tests/baselines/reference/for-of26.js

@@ -0,0 +1,27 @@
+//// [for-of26.ts]
+var x: any;
+for (var v of new StringIterator) { }
+
+class StringIterator {
+    next() {
+        return x;
+    }
+    [Symbol.iterator]() {
+        return this;
+    }
+}
+
+//// [for-of26.js]
+var x;
+for (var v of new StringIterator) { }
+var StringIterator = (function () {
+    function StringIterator() {
+    }
+    StringIterator.prototype.next = function () {
+        return x;
+    };
+    StringIterator.prototype[Symbol.iterator] = function () {
+        return this;
+    };
+    return StringIterator;
+})();

tests/baselines/reference/for-of26.types

@@ -0,0 +1,27 @@
+=== tests/cases/conformance/es6/for-ofStatements/for-of26.ts ===
+var x: any;
+>x : any
+
+for (var v of new StringIterator) { }
+>v : any
+>new StringIterator : StringIterator
+>StringIterator : typeof StringIterator
+
+class StringIterator {
+>StringIterator : StringIterator
+
+    next() {
+>next : () => any
+
+        return x;
+>x : any
+    }
+    [Symbol.iterator]() {
+>Symbol.iterator : symbol
+>Symbol : SymbolConstructor
+>iterator : symbol
+
+        return this;
+>this : StringIterator
+    }
+}

tests/baselines/reference/for-of27.js

@@ -0,0 +1,14 @@
+//// [for-of27.ts]
+for (var v of new StringIterator) { }
+
+class StringIterator {
+    [Symbol.iterator]: any;
+}
+
+//// [for-of27.js]
+for (var v of new StringIterator) { }
+var StringIterator = (function () {
+    function StringIterator() {
+    }
+    return StringIterator;
+})();

tests/baselines/reference/for-of27.types

@@ -0,0 +1,14 @@
+=== tests/cases/conformance/es6/for-ofStatements/for-of27.ts ===
+for (var v of new StringIterator) { }
+>v : any
+>new StringIterator : StringIterator
+>StringIterator : typeof StringIterator
+
+class StringIterator {
+>StringIterator : StringIterator
+
+    [Symbol.iterator]: any;
+>Symbol.iterator : symbol
+>Symbol : SymbolConstructor
+>iterator : symbol
+}

tests/baselines/reference/for-of28.js

@@ -0,0 +1,20 @@
+//// [for-of28.ts]
+for (var v of new StringIterator) { }
+
+class StringIterator {
+    next: any;
+    [Symbol.iterator]() {
+        return this;
+    }
+}
+
+//// [for-of28.js]
+for (var v of new StringIterator) { }
+var StringIterator = (function () {
+    function StringIterator() {
+    }
+    StringIterator.prototype[Symbol.iterator] = function () {
+        return this;
+    };
+    return StringIterator;
+})();

tests/baselines/reference/for-of28.types

@@ -0,0 +1,21 @@
+=== tests/cases/conformance/es6/for-ofStatements/for-of28.ts ===
+for (var v of new StringIterator) { }
+>v : any
+>new StringIterator : StringIterator
+>StringIterator : typeof StringIterator
+
+class StringIterator {
+>StringIterator : StringIterator
+
+    next: any;
+>next : any
+
+    [Symbol.iterator]() {
+>Symbol.iterator : symbol
+>Symbol : SymbolConstructor
+>iterator : symbol
+
+        return this;
+>this : StringIterator
+    }
+}

tests/cases/conformance/es6/for-ofStatements/for-of24.ts

@@ -0,0 +1,3 @@
+//@target: ES6
+var x: any;
+for (var v of x) { }

tests/cases/conformance/es6/for-ofStatements/for-of25.ts

@@ -0,0 +1,9 @@
+//@target: ES6
+var x: any;
+for (var v of new StringIterator) { }
+
+class StringIterator {
+    [Symbol.iterator]() {
+        return x;
+    }
+}

tests/cases/conformance/es6/for-ofStatements/for-of26.ts

@@ -0,0 +1,12 @@
+//@target: ES6
+var x: any;
+for (var v of new StringIterator) { }
+
+class StringIterator {
+    next() {
+        return x;
+    }
+    [Symbol.iterator]() {
+        return this;
+    }
+}

tests/cases/conformance/es6/for-ofStatements/for-of27.ts

@@ -0,0 +1,6 @@
+//@target: ES6
+for (var v of new StringIterator) { }
+
+class StringIterator {
+    [Symbol.iterator]: any;
+}

tests/cases/conformance/es6/for-ofStatements/for-of28.ts

@@ -0,0 +1,9 @@
+//@target: ES6
+for (var v of new StringIterator) { }
+
+class StringIterator {
+    next: any;
+    [Symbol.iterator]() {
+        return this;
+    }
+}