tests/cases/conformance/types/thisType/thisTypeAndConstraints.ts(9,9): error TS2322: Type 'A' is not assignable to type 'U'.
  'A' is assignable to the constraint of type 'U', but 'U' could be instantiated with a different subtype of constraint 'A'.
tests/cases/conformance/types/thisType/thisTypeAndConstraints.ts(11,5): error TS2322: Type 'A' is not assignable to type 'T'.
  'A' is assignable to the constraint of type 'T', but 'T' could be instantiated with a different subtype of constraint 'A'.
tests/cases/conformance/types/thisType/thisTypeAndConstraints.ts(16,9): error TS2322: Type 'A' is not assignable to type 'T'.
  'A' is assignable to the constraint of type 'T', but 'T' could be instantiated with a different subtype of constraint 'A'.
tests/cases/conformance/types/thisType/thisTypeAndConstraints.ts(19,9): error TS2322: Type 'A' is not assignable to type 'U'.
  'A' is assignable to the constraint of type 'U', but 'U' could be instantiated with a different subtype of constraint 'A'.


==== tests/cases/conformance/types/thisType/thisTypeAndConstraints.ts (4 errors) ====
    class A {
        self() {
            return this;
        }
    }
    
    function f<T extends A>(x: T) {
        function g<U extends T>(x: U) {
            x = x.self();
            ~
!!! error TS2322: Type 'A' is not assignable to type 'U'.
!!! error TS2322:   'A' is assignable to the constraint of type 'U', but 'U' could be instantiated with a different subtype of constraint 'A'.
        }
        x = x.self();
        ~
!!! error TS2322: Type 'A' is not assignable to type 'T'.
!!! error TS2322:   'A' is assignable to the constraint of type 'T', but 'T' could be instantiated with a different subtype of constraint 'A'.
    }
    
    class B<T extends A> {
        foo(x: T) {
            x = x.self();
            ~
!!! error TS2322: Type 'A' is not assignable to type 'T'.
!!! error TS2322:   'A' is assignable to the constraint of type 'T', but 'T' could be instantiated with a different subtype of constraint 'A'.
        }
        bar<U extends T>(x: U) {
            x = x.self();
            ~
!!! error TS2322: Type 'A' is not assignable to type 'U'.
!!! error TS2322:   'A' is assignable to the constraint of type 'U', but 'U' could be instantiated with a different subtype of constraint 'A'.
        }
    }
    