==== tests/cases/compiler/constraints0.ts (1 errors) ====
    interface A {
    	a: number;
    }
    
    interface B {
    	b: string;
    }
    
    interface C<T extends A> {
        x: T;
    }
    
    var v1: C<A>; // should work
    var v2: C<B>; // should not work
            ~~~~
!!! Type 'B' does not satisfy the constraint 'A':
!!!   Property 'a' is missing in type 'B'.
    
    var y = v1.x.a; // 'a' should be of type 'number'