Allow extending from any

src/compiler/checker.ts

@@ -4617,7 +4617,7 @@ namespace ts {
                     error(type.symbol.valueDeclaration, Diagnostics._0_is_referenced_directly_or_indirectly_in_its_own_base_expression, symbolToString(type.symbol));
                     return type.resolvedBaseConstructorType = unknownType;
                 }
-                if (baseConstructorType !== unknownType && baseConstructorType !== nullWideningType && !isConstructorType(baseConstructorType)) {
+                if (baseConstructorType !== anyType && baseConstructorType !== unknownType && baseConstructorType !== nullWideningType && !isConstructorType(baseConstructorType)) {
                     error(baseTypeNode.expression, Diagnostics.Type_0_is_not_a_constructor_function_type, typeToString(baseConstructorType));
                     return type.resolvedBaseConstructorType = unknownType;
                 }
@@ -4649,7 +4649,7 @@ namespace ts {
         function resolveBaseTypesOfClass(type: InterfaceType): void {
             type.resolvedBaseTypes = type.resolvedBaseTypes || emptyArray;
             const baseConstructorType = getApparentType(getBaseConstructorTypeOfClass(type));
-            if (!(baseConstructorType.flags & (TypeFlags.Object | TypeFlags.Intersection))) {
+            if (!(baseConstructorType.flags & (TypeFlags.Object | TypeFlags.Intersection | TypeFlags.Any))) {
                 return;
             }
             const baseTypeNode = getBaseTypeNodeOfClass(type);
@@ -4662,6 +4662,9 @@ namespace ts {
                 // type arguments in the same manner as a type reference to get the same error reporting experience.
                 baseType = getTypeFromClassOrInterfaceReference(baseTypeNode, baseConstructorType.symbol);
             }
+            else if (baseConstructorType.flags & TypeFlags.Any) {
+                baseType = anyType;
+            }
             else {
                 // The class derives from a "class-like" constructor function, check that we have at least one construct signature
                 // with a matching number of type parameters and use the return type of the first instantiated signature. Elsewhere
@@ -4715,10 +4718,11 @@ namespace ts {
             return true;
         }
 
-        // A valid base type is any non-generic object type or intersection of non-generic
+        // A valid base type is `any`, any non-generic object type or intersection of non-generic
         // object types.
         function isValidBaseType(type: Type): boolean {
-            return type.flags & (TypeFlags.Object | TypeFlags.NonPrimitive) && !isGenericMappedType(type) ||
+            return !!(type.flags & TypeFlags.Any) ||
+                type.flags & (TypeFlags.Object | TypeFlags.NonPrimitive) && !isGenericMappedType(type) ||
                 type.flags & TypeFlags.Intersection && !forEach((<IntersectionType>type).types, t => !isValidBaseType(t));
         }
 
@@ -5130,7 +5134,9 @@ namespace ts {
                     addInheritedMembers(members, getPropertiesOfType(instantiatedBaseType));
                     callSignatures = concatenate(callSignatures, getSignaturesOfType(instantiatedBaseType, SignatureKind.Call));
                     constructSignatures = concatenate(constructSignatures, getSignaturesOfType(instantiatedBaseType, SignatureKind.Construct));
-                    stringIndexInfo = stringIndexInfo || getIndexInfoOfType(instantiatedBaseType, IndexKind.String);
+                    stringIndexInfo = stringIndexInfo || (instantiatedBaseType === anyType ?
+                                                          createIndexInfo(anyType, /*isReadonly*/ false) :
+                                                          getIndexInfoOfType(instantiatedBaseType, IndexKind.String));
                     numberIndexInfo = numberIndexInfo || getIndexInfoOfType(instantiatedBaseType, IndexKind.Number);
                 }
             }
@@ -5371,6 +5377,7 @@ namespace ts {
                 // Combinations of function, class, enum and module
                 let members = emptySymbols;
                 let constructSignatures: Signature[] = emptyArray;
+                let stringIndexInfo: IndexInfo = undefined;
                 if (symbol.exports) {
                     members = getExportsOfSymbol(symbol);
                 }
@@ -5385,9 +5392,12 @@ namespace ts {
                         members = createSymbolTable(getNamedMembers(members));
                         addInheritedMembers(members, getPropertiesOfType(baseConstructorType));
                     }
+                    else if (baseConstructorType === anyType) {
+                        stringIndexInfo = createIndexInfo(anyType, /*isReadonly*/ false);
+                    }
                 }
                 const numberIndexInfo = symbol.flags & SymbolFlags.Enum ? enumNumberIndexInfo : undefined;
-                setStructuredTypeMembers(type, members, emptyArray, constructSignatures, undefined, numberIndexInfo);
+                setStructuredTypeMembers(type, members, emptyArray, constructSignatures, stringIndexInfo, numberIndexInfo);
                 // We resolve the members before computing the signatures because a signature may use
                 // typeof with a qualified name expression that circularly references the type we are
                 // in the process of resolving (see issue #6072). The temporarily empty signature list

tests/baselines/reference/extendFromAny.errors.txt

@@ -0,0 +1,21 @@
+tests/cases/compiler/extendFromAny.ts(8,9): error TS2339: Property 'length' does not exist on type 'number'.
+tests/cases/compiler/extendFromAny.ts(9,10): error TS2339: Property 'length' does not exist on type 'number'.
+
+
+==== tests/cases/compiler/extendFromAny.ts (2 errors) ====
+    declare var Base: any;
+    class C extends Base {
+        known = 1;
+        static sknown = 2;
+    }
+
+    let c = new C();
+    c.known.length; // error, 'known' has no 'length' property
+            ~~~~~~
+!!! error TS2339: Property 'length' does not exist on type 'number'.
+    C.sknown.length; // error, 'sknown' has no 'length' property
+             ~~~~~~
+!!! error TS2339: Property 'length' does not exist on type 'number'.
+    c.unknown.length; // ok, unknown: any
+    C.sunknown.length; // ok: sunknown: any
+

tests/baselines/reference/extendFromAny.js

@@ -0,0 +1,40 @@
+//// [extendFromAny.ts]
+declare var Base: any;
+class C extends Base {
+    known = 1;
+    static sknown = 2;
+}
+
+let c = new C();
+c.known.length; // error, 'known' has no 'length' property
+C.sknown.length; // error, 'sknown' has no 'length' property
+c.unknown.length; // ok, unknown: any
+C.sunknown.length; // ok: sunknown: any
+
+
+//// [extendFromAny.js]
+var __extends = (this && this.__extends) || (function () {
+    var extendStatics = Object.setPrototypeOf ||
+        ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
+        function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
+    return function (d, b) {
+        extendStatics(d, b);
+        function __() { this.constructor = d; }
+        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+    };
+})();
+var C = (function (_super) {
+    __extends(C, _super);
+    function C() {
+        var _this = _super !== null && _super.apply(this, arguments) || this;
+        _this.known = 1;
+        return _this;
+    }
+    return C;
+}(Base));
+C.sknown = 2;
+var c = new C();
+c.known.length; // error, 'known' has no 'length' property
+C.sknown.length; // error, 'sknown' has no 'length' property
+c.unknown.length; // ok, unknown: any
+C.sunknown.length; // ok: sunknown: any

tests/baselines/reference/extendsUntypedModule.symbols

@@ -0,0 +1,8 @@
+=== /a.ts ===
+import Foo from "foo";
+>Foo : Symbol(Foo, Decl(a.ts, 0, 6))
+
+class A extends Foo { }
+>A : Symbol(A, Decl(a.ts, 0, 22))
+>Foo : Symbol(Foo, Decl(a.ts, 0, 6))
+

tests/baselines/reference/extendsUntypedModule.types

@@ -0,0 +1,8 @@
+=== /a.ts ===
+import Foo from "foo";
+>Foo : any
+
+class A extends Foo { }
+>A : A
+>Foo : any
+

tests/baselines/reference/generatorTypeCheck40.errors.txt

@@ -1,12 +1,9 @@
-tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck40.ts(2,21): error TS2507: Type 'any' is not a constructor function type.
 tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck40.ts(2,22): error TS1163: A 'yield' expression is only allowed in a generator body.
 
 
-==== tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck40.ts (2 errors) ====
+==== tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck40.ts (1 errors) ====
     function* g() {
         class C extends (yield 0) { }
-                        ~~~~~~~~~
-!!! error TS2507: Type 'any' is not a constructor function type.
                          ~~~~~
 !!! error TS1163: A 'yield' expression is only allowed in a generator body.
     }

tests/baselines/reference/generatorTypeCheck55.errors.txt

@@ -1,12 +1,9 @@
-tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck55.ts(2,29): error TS2507: Type 'any' is not a constructor function type.
 tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck55.ts(2,30): error TS1163: A 'yield' expression is only allowed in a generator body.
 
 
-==== tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck55.ts (2 errors) ====
+==== tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck55.ts (1 errors) ====
     function* g() {
         var x = class C extends (yield) {};
-                                ~~~~~~~
-!!! error TS2507: Type 'any' is not a constructor function type.
                                  ~~~~~
 !!! error TS1163: A 'yield' expression is only allowed in a generator body.
     }

tests/baselines/reference/generatorTypeCheck60.errors.txt

@@ -1,12 +1,9 @@
-tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck60.ts(2,21): error TS2507: Type 'any' is not a constructor function type.
 tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck60.ts(2,22): error TS1163: A 'yield' expression is only allowed in a generator body.
 
 
-==== tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck60.ts (2 errors) ====
+==== tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck60.ts (1 errors) ====
     function* g() {
         class C extends (yield) {};
-                        ~~~~~~~
-!!! error TS2507: Type 'any' is not a constructor function type.
                          ~~~~~
 !!! error TS1163: A 'yield' expression is only allowed in a generator body.
     }

tests/baselines/reference/parserGenericsInTypeContexts1.errors.txt

@@ -1,4 +1,5 @@
 tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts1.ts(1,17): error TS2304: Cannot find name 'A'.
+tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts1.ts(1,19): error TS2304: Cannot find name 'T'.
 tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts1.ts(1,33): error TS2304: Cannot find name 'B'.
 tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts1.ts(4,9): error TS2315: Type 'C' is not generic.
 tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts1.ts(5,9): error TS2304: Cannot find name 'D'.
@@ -9,10 +10,12 @@ tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts
 tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts1.ts(14,16): error TS2304: Cannot find name 'F'.
 
 
-==== tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts1.ts (9 errors) ====
+==== tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts1.ts (10 errors) ====
     class C extends A<T> implements B<T> {
                     ~
 !!! error TS2304: Cannot find name 'A'.
+                      ~
+!!! error TS2304: Cannot find name 'T'.
                                     ~
 !!! error TS2304: Cannot find name 'B'.
     }

tests/baselines/reference/parserGenericsInTypeContexts2.errors.txt

@@ -1,4 +1,6 @@
 tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts2.ts(1,17): error TS2304: Cannot find name 'A'.
+tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts2.ts(1,19): error TS2304: Cannot find name 'X'.
+tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts2.ts(1,25): error TS2304: Cannot find name 'Y'.
 tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts2.ts(1,45): error TS2304: Cannot find name 'B'.
 tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts2.ts(4,9): error TS2315: Type 'C' is not generic.
 tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts2.ts(5,9): error TS2304: Cannot find name 'D'.
@@ -9,10 +11,14 @@ tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts
 tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts2.ts(14,16): error TS2304: Cannot find name 'F'.
 
 
-==== tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts2.ts (9 errors) ====
+==== tests/cases/conformance/parser/ecmascript5/Generics/parserGenericsInTypeContexts2.ts (11 errors) ====
     class C extends A<X<T>, Y<Z<T>>> implements B<X<T>, Y<Z<T>>> {
                     ~
 !!! error TS2304: Cannot find name 'A'.
+                      ~
+!!! error TS2304: Cannot find name 'X'.
+                            ~
+!!! error TS2304: Cannot find name 'Y'.
                                                 ~
 !!! error TS2304: Cannot find name 'B'.
     }

tests/baselines/reference/recursiveBaseCheck3.errors.txt

@@ -1,10 +1,9 @@
 tests/cases/compiler/recursiveBaseCheck3.ts(1,7): error TS2506: 'A' is referenced directly or indirectly in its own base expression.
 tests/cases/compiler/recursiveBaseCheck3.ts(1,20): error TS2449: Class 'C' used before its declaration.
 tests/cases/compiler/recursiveBaseCheck3.ts(2,7): error TS2506: 'C' is referenced directly or indirectly in its own base expression.
-tests/cases/compiler/recursiveBaseCheck3.ts(4,9): error TS2339: Property 'blah' does not exist on type 'C<{}>'.
 
 
-==== tests/cases/compiler/recursiveBaseCheck3.ts (4 errors) ====
+==== tests/cases/compiler/recursiveBaseCheck3.ts (3 errors) ====
     class A<T> extends C<T> { }
           ~
 !!! error TS2506: 'A' is referenced directly or indirectly in its own base expression.
@@ -14,6 +13,4 @@ tests/cases/compiler/recursiveBaseCheck3.ts(4,9): error TS2339: Property 'blah'
           ~
 !!! error TS2506: 'C' is referenced directly or indirectly in its own base expression.
 
-    (new C).blah;
-            ~~~~
-!!! error TS2339: Property 'blah' does not exist on type 'C<{}>'.
+    (new C).blah;

tests/baselines/reference/recursiveBaseCheck4.errors.txt

@@ -1,11 +1,8 @@
 tests/cases/compiler/recursiveBaseCheck4.ts(1,7): error TS2506: 'M' is referenced directly or indirectly in its own base expression.
-tests/cases/compiler/recursiveBaseCheck4.ts(2,9): error TS2339: Property 'blah' does not exist on type 'M<{}>'.
 
 
-==== tests/cases/compiler/recursiveBaseCheck4.ts (2 errors) ====
+==== tests/cases/compiler/recursiveBaseCheck4.ts (1 errors) ====
     class M<T> extends M<string> { }
           ~
 !!! error TS2506: 'M' is referenced directly or indirectly in its own base expression.
-    (new M).blah;
-            ~~~~
-!!! error TS2339: Property 'blah' does not exist on type 'M<{}>'.
+    (new M).blah;

tests/baselines/reference/recursiveBaseCheck6.errors.txt

@@ -1,11 +1,8 @@
 tests/cases/compiler/recursiveBaseCheck6.ts(1,7): error TS2506: 'S18' is referenced directly or indirectly in its own base expression.
-tests/cases/compiler/recursiveBaseCheck6.ts(2,13): error TS2339: Property 'blah' does not exist on type 'S18<{}>'.
 
 
-==== tests/cases/compiler/recursiveBaseCheck6.ts (2 errors) ====
+==== tests/cases/compiler/recursiveBaseCheck6.ts (1 errors) ====
     class S18<A> extends S18<{ S19: A; }>{ }
           ~~~
 !!! error TS2506: 'S18' is referenced directly or indirectly in its own base expression.
-    (new S18()).blah;
-                ~~~~
-!!! error TS2339: Property 'blah' does not exist on type 'S18<{}>'.
+    (new S18()).blah;

tests/baselines/reference/thisInInvalidContexts.errors.txt

@@ -3,12 +3,11 @@ tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts(14,15):
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts(22,15): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts(28,13): error TS2331: 'this' cannot be referenced in a module or namespace body.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts(36,13): error TS2526: A 'this' type is available only in a non-static member of a class or interface.
-tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts(38,25): error TS2507: Type 'any' is not a constructor function type.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts(44,9): error TS2332: 'this' cannot be referenced in current location.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts(45,9): error TS2332: 'this' cannot be referenced in current location.
 
 
-==== tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts (8 errors) ====
+==== tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts (7 errors) ====
     //'this' in static member initializer
     class ErrClass1 {
         static t = this; // Error
@@ -57,8 +56,6 @@ tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts(45,9):
 !!! error TS2526: A 'this' type is available only in a non-static member of a class or interface.
 
     class ErrClass3 extends this {
-                            ~~~~
-!!! error TS2507: Type 'any' is not a constructor function type.
 
     }
 

tests/baselines/reference/thisInInvalidContextsExternalModule.errors.txt

@@ -3,12 +3,11 @@ tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalMod
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalModule.ts(22,15): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalModule.ts(28,13): error TS2331: 'this' cannot be referenced in a module or namespace body.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalModule.ts(36,13): error TS2526: A 'this' type is available only in a non-static member of a class or interface.
-tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalModule.ts(38,25): error TS2507: Type 'any' is not a constructor function type.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalModule.ts(44,9): error TS2332: 'this' cannot be referenced in current location.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalModule.ts(45,9): error TS2332: 'this' cannot be referenced in current location.
 
 
-==== tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalModule.ts (8 errors) ====
+==== tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalModule.ts (7 errors) ====
     //'this' in static member initializer
     class ErrClass1 {
         static t = this; // Error
@@ -57,8 +56,6 @@ tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalMod
 !!! error TS2526: A 'this' type is available only in a non-static member of a class or interface.
 
     class ErrClass3 extends this {
-                            ~~~~
-!!! error TS2507: Type 'any' is not a constructor function type.
 
     }