==== tests/cases/compiler/multipleInheritance.ts (3 errors) ====
    class B1 {
        public x;
    }
    
    class B2 {
        public x;
    }
    
    class C extends B1, B2 { // duplicate member
            ~~~~~~~~~~~~~~
!!! multipleInheritance.ts(9,9): error TS1026: Classes can only extend a single class.
    }
    
    class D1 extends B1 {
    }
    
    class D2 extends B2 {
    }
    
    class E extends D1, D2 { // nope, duplicate member
            ~~~~~~~~~~~~~~
!!! multipleInheritance.ts(18,9): error TS1026: Classes can only extend a single class.
    }
    
    class N {
        public y:number;
    }
    
    class ND extends N { // any is assignable to number
        public y;
    }
    
    class Good {
        public f:() => number = function() { return 0; }
        public g() { return 0; }
    }
    
    class Baad extends Good {
          ~~~~
!!! multipleInheritance.ts(34,7): error TS2141: Class 'Baad' cannot extend class 'Good':
!!! 	Class 'Baad' defines instance member function 'f', but extended class 'Good' defines it as instance member property.
        public f(): number { return 0; }
        public g(n:number) { return 0; }
    }
    