==== tests/cases/compiler/interfaceDeclaration1.ts (6 errors) ====
    interface I1 {
        item:number;
        item:number;
        ~~~~
!!! Duplicate identifier 'item'.
    }
    
    interface I2 {
        item:any;
        item:number;
        ~~~~
!!! Duplicate identifier 'item'.
    }
    
    interface I3 {
        prototype:number;
    }
    
    interface I4 {
        class:number;
        number:number;
        super:number;
        prototype:number;
    }
    
    interface I5 extends I5 { 
              ~~
!!! Type 'I5' recursively references itself as a base type.
        foo():void;
    }
    
    interface I6 {
    	():void;
    }
    
    interface I7 extends I6 { }
    
    var v1:I7;
    v1();
    
    class C1 implements I3 {
          ~~
!!! Class 'C1' incorrectly implements interface 'I3':
!!!   Property 'prototype' is missing in type 'C1'.
        constructor() {
            var prototype: number = 3;
        }
    }
    
    interface i8 extends i9 { }
              ~~
!!! Type 'i8' recursively references itself as a base type.
    interface i9 extends i8 { }
    
    interface i10 {
    	foo():number;
    }
    
    interface i11{
    	foo():string;
    }
    
    interface i12 extends i10, i11 { }
              ~~~
!!! Interface 'i12' cannot simultaneously extend types 'i10' and 'i11':
!!!   Named properties 'foo' of types 'i10' and 'i11' are not identical.