==== tests/cases/compiler/apparentTypeSupertype.ts (1 errors) ====
    // subtype checks use the apparent type of the target type
    // S is a subtype of a type T, and T is a supertype of S, if one of the following is true, where S' denotes the apparent type (section 3.8.1) of S:
    
    class Base {
        x: string;
    }
    
    // is String (S) a subtype of U extends String (T)? Would only be true if we used the apparent type of U (T)
    class Derived<U extends String> extends Base { // error
          ~~~~~~~
!!! apparentTypeSupertype.ts(9,7): error TS2141: Class 'Derived<U>' cannot extend class 'Base':
!!! 	Types of property 'x' of types 'Derived<U>' and 'Base' are incompatible.
        x: U;
    }