==== tests/cases/conformance/types/typeRelationships/apparentType/apparentTypeSubtyping.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: U; } // 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 extends Base { // error ~~~~~~~ !!! Class 'Derived' incorrectly extends base class 'Base': !!! Types of property 'x' are incompatible: !!! Type 'String' is not assignable to type 'string'. x: String; } class Base2 { x: String; static s: String; } // is U extends String (S) a subtype of String (T)? Apparent type of U is String so it succeeds class Derived2 extends Base2 { // error because of the prototype's not matching, not because of the instance side x: U; }