Merge pull request #9180 from HerringtonDarkholme/interface

[Fix #9004] Improve error message for extending interface

tests/cases/compiler/classExtendsInterface.ts

@@ -1,7 +1,7 @@
 interface Comparable {}
 class A extends Comparable {}
 class B implements Comparable {}
- 
+
 interface Comparable2<T> {}
 class A2<T> extends Comparable2<T> {}
 class B2<T> implements Comparable2<T> {}

tests/cases/compiler/classExtendsInterfaceInExpression.ts

@@ -0,0 +1,7 @@
+interface A {}
+
+function factory(a: any): {new(): Object} {
+  return null;
+}
+
+class C extends factory(A) {}

tests/cases/compiler/classExtendsInterfaceInModule.ts

@@ -0,0 +1,14 @@
+module M {
+  export interface I1 {}
+  export interface I2<T> {}
+}
+class C1 extends M.I1 {}
+class C2<T> extends M.I2<T> {}
+
+module Mod {
+	export namespace Nested {
+		export interface I {}
+	}
+}
+
+class D extends Mod.Nested.I {}