callSignatureAssignabilityInInheritance6.ts(5,14): error TS2564: Property 'foo' has no initializer and is not definitely assigned in the constructor.
callSignatureAssignabilityInInheritance6.ts(6,30): error TS2564: Property 'bar' has no initializer and is not definitely assigned in the constructor.
callSignatureAssignabilityInInheritance6.ts(7,34): error TS2564: Property 'baz' has no initializer and is not definitely assigned in the constructor.
callSignatureAssignabilityInInheritance6.ts(8,35): error TS2564: Property 'bing' has no initializer and is not definitely assigned in the constructor.
callSignatureAssignabilityInInheritance6.ts(24,11): error TS2430: Interface 'I<T>' incorrectly extends interface 'A'.
  Types of property 'a' are incompatible.
    Type '(x: T) => T[]' is not assignable to type '<T>(x: T) => T[]'.
      Types of parameters 'x' and 'x' are incompatible.
        Type 'T' is not assignable to type 'T'. Two different types with this name exist, but they are unrelated.
          'T' could be instantiated with an arbitrary type which could be unrelated to 'T'.
callSignatureAssignabilityInInheritance6.ts(28,11): error TS2430: Interface 'I2<T>' incorrectly extends interface 'A'.
  Types of property 'a2' are incompatible.
    Type '(x: T) => string[]' is not assignable to type '<T>(x: T) => string[]'.
      Types of parameters 'x' and 'x' are incompatible.
        Type 'T' is not assignable to type 'T'. Two different types with this name exist, but they are unrelated.
          'T' could be instantiated with an arbitrary type which could be unrelated to 'T'.
callSignatureAssignabilityInInheritance6.ts(32,11): error TS2430: Interface 'I3<T>' incorrectly extends interface 'A'.
  Types of property 'a3' are incompatible.
    Type '(x: T) => T' is not assignable to type '<T>(x: T) => void'.
      Types of parameters 'x' and 'x' are incompatible.
        Type 'T' is not assignable to type 'T'. Two different types with this name exist, but they are unrelated.
          'T' could be instantiated with an arbitrary type which could be unrelated to 'T'.
callSignatureAssignabilityInInheritance6.ts(36,11): error TS2430: Interface 'I4<T>' incorrectly extends interface 'A'.
  Types of property 'a4' are incompatible.
    Type '<U>(x: T, y: U) => string' is not assignable to type '<T, U>(x: T, y: U) => string'.
      Types of parameters 'x' and 'x' are incompatible.
        Type 'T' is not assignable to type 'T'. Two different types with this name exist, but they are unrelated.
          'T' could be instantiated with an arbitrary type which could be unrelated to 'T'.
callSignatureAssignabilityInInheritance6.ts(40,11): error TS2430: Interface 'I5<T>' incorrectly extends interface 'A'.
  Types of property 'a5' are incompatible.
    Type '<U>(x: (arg: T) => U) => T' is not assignable to type '<T, U>(x: (arg: T) => U) => T'.
      Types of parameters 'x' and 'x' are incompatible.
        Types of parameters 'arg' and 'arg' are incompatible.
          Type 'T' is not assignable to type 'T'. Two different types with this name exist, but they are unrelated.
            'T' could be instantiated with an arbitrary type which could be unrelated to 'T'.
callSignatureAssignabilityInInheritance6.ts(44,11): error TS2430: Interface 'I7<T>' incorrectly extends interface 'A'.
  Types of property 'a11' are incompatible.
    Type '<U>(x: { foo: T; }, y: { foo: U; bar: U; }) => Base' is not assignable to type '<T>(x: { foo: T; }, y: { foo: T; bar: T; }) => Base'.
      Types of parameters 'x' and 'x' are incompatible.
        Type '{ foo: T; }' is not assignable to type '{ foo: T; }'. Two different types with this name exist, but they are unrelated.
          Types of property 'foo' are incompatible.
            Type 'T' is not assignable to type 'T'. Two different types with this name exist, but they are unrelated.
              'T' could be instantiated with an arbitrary type which could be unrelated to 'T'.
callSignatureAssignabilityInInheritance6.ts(48,11): error TS2430: Interface 'I9<T>' incorrectly extends interface 'A'.
  Types of property 'a16' are incompatible.
    Type '(x: { a: T; b: T; }) => T[]' is not assignable to type '<T extends Base>(x: { a: T; b: T; }) => T[]'.
      Types of parameters 'x' and 'x' are incompatible.
        Type '{ a: T; b: T; }' is not assignable to type '{ a: T; b: T; }'. Two different types with this name exist, but they are unrelated.
          Types of property 'a' are incompatible.
            Type 'T' is not assignable to type 'T'. Two different types with this name exist, but they are unrelated.
              'T' could be instantiated with an arbitrary type which could be unrelated to 'T'.


==== callSignatureAssignabilityInInheritance6.ts (11 errors) ====
    // checking subtype relations for function types as it relates to contextual signature instantiation
    // same as subtypingWithCallSignatures4 but using class type parameters instead of generic signatures
    // all are errors
    
    class Base { foo: string; }
                 ~~~
!!! error TS2564: Property 'foo' has no initializer and is not definitely assigned in the constructor.
    class Derived extends Base { bar: string; }
                                 ~~~
!!! error TS2564: Property 'bar' has no initializer and is not definitely assigned in the constructor.
    class Derived2 extends Derived { baz: string; }
                                     ~~~
!!! error TS2564: Property 'baz' has no initializer and is not definitely assigned in the constructor.
    class OtherDerived extends Base { bing: string; }
                                      ~~~~
!!! error TS2564: Property 'bing' has no initializer and is not definitely assigned in the constructor.
    
    interface A { // T
        // M's
        a: <T>(x: T) => T[];
        a2: <T>(x: T) => string[];
        a3: <T>(x: T) => void;
        a4: <T,U>(x: T, y: U) => string;
        a5: <T,U>(x: (arg: T) => U) => T;
        a6: <T extends Base>(x: (arg: T) => Derived) => T;
        a11: <T>(x: { foo: T }, y: { foo: T; bar: T }) => Base;
        a15: <T>(x: { a: T; b: T }) => T[];
        a16: <T extends Base>(x: { a: T; b: T }) => T[];
    }
    
    // S's
    interface I<T> extends A {
              ~
!!! error TS2430: Interface 'I<T>' incorrectly extends interface 'A'.
!!! error TS2430:   Types of property 'a' are incompatible.
!!! error TS2430:     Type '(x: T) => T[]' is not assignable to type '<T>(x: T) => T[]'.
!!! error TS2430:       Types of parameters 'x' and 'x' are incompatible.
!!! error TS2430:         Type 'T' is not assignable to type 'T'. Two different types with this name exist, but they are unrelated.
!!! error TS2430:           'T' could be instantiated with an arbitrary type which could be unrelated to 'T'.
!!! related TS2208 callSignatureAssignabilityInInheritance6.ts:12:9: This type parameter might need an `extends T` constraint.
        a: (x: T) => T[]; 
    }
    
    interface I2<T> extends A {
              ~~
!!! error TS2430: Interface 'I2<T>' incorrectly extends interface 'A'.
!!! error TS2430:   Types of property 'a2' are incompatible.
!!! error TS2430:     Type '(x: T) => string[]' is not assignable to type '<T>(x: T) => string[]'.
!!! error TS2430:       Types of parameters 'x' and 'x' are incompatible.
!!! error TS2430:         Type 'T' is not assignable to type 'T'. Two different types with this name exist, but they are unrelated.
!!! error TS2430:           'T' could be instantiated with an arbitrary type which could be unrelated to 'T'.
!!! related TS2208 callSignatureAssignabilityInInheritance6.ts:13:10: This type parameter might need an `extends T` constraint.
        a2: (x: T) => string[]; 
    }
    
    interface I3<T> extends A {
              ~~
!!! error TS2430: Interface 'I3<T>' incorrectly extends interface 'A'.
!!! error TS2430:   Types of property 'a3' are incompatible.
!!! error TS2430:     Type '(x: T) => T' is not assignable to type '<T>(x: T) => void'.
!!! error TS2430:       Types of parameters 'x' and 'x' are incompatible.
!!! error TS2430:         Type 'T' is not assignable to type 'T'. Two different types with this name exist, but they are unrelated.
!!! error TS2430:           'T' could be instantiated with an arbitrary type which could be unrelated to 'T'.
!!! related TS2208 callSignatureAssignabilityInInheritance6.ts:14:10: This type parameter might need an `extends T` constraint.
        a3: (x: T) => T;
    }
    
    interface I4<T> extends A {
              ~~
!!! error TS2430: Interface 'I4<T>' incorrectly extends interface 'A'.
!!! error TS2430:   Types of property 'a4' are incompatible.
!!! error TS2430:     Type '<U>(x: T, y: U) => string' is not assignable to type '<T, U>(x: T, y: U) => string'.
!!! error TS2430:       Types of parameters 'x' and 'x' are incompatible.
!!! error TS2430:         Type 'T' is not assignable to type 'T'. Two different types with this name exist, but they are unrelated.
!!! error TS2430:           'T' could be instantiated with an arbitrary type which could be unrelated to 'T'.
!!! related TS2208 callSignatureAssignabilityInInheritance6.ts:15:10: This type parameter might need an `extends T` constraint.
        a4: <U>(x: T, y: U) => string; 
    }
    
    interface I5<T> extends A {
              ~~
!!! error TS2430: Interface 'I5<T>' incorrectly extends interface 'A'.
!!! error TS2430:   Types of property 'a5' are incompatible.
!!! error TS2430:     Type '<U>(x: (arg: T) => U) => T' is not assignable to type '<T, U>(x: (arg: T) => U) => T'.
!!! error TS2430:       Types of parameters 'x' and 'x' are incompatible.
!!! error TS2430:         Types of parameters 'arg' and 'arg' are incompatible.
!!! error TS2430:           Type 'T' is not assignable to type 'T'. Two different types with this name exist, but they are unrelated.
!!! error TS2430:             'T' could be instantiated with an arbitrary type which could be unrelated to 'T'.
!!! related TS2208 callSignatureAssignabilityInInheritance6.ts:40:14: This type parameter might need an `extends T` constraint.
        a5: <U>(x: (arg: T) => U) => T; 
    }
    
    interface I7<T> extends A {
              ~~
!!! error TS2430: Interface 'I7<T>' incorrectly extends interface 'A'.
!!! error TS2430:   Types of property 'a11' are incompatible.
!!! error TS2430:     Type '<U>(x: { foo: T; }, y: { foo: U; bar: U; }) => Base' is not assignable to type '<T>(x: { foo: T; }, y: { foo: T; bar: T; }) => Base'.
!!! error TS2430:       Types of parameters 'x' and 'x' are incompatible.
!!! error TS2430:         Type '{ foo: T; }' is not assignable to type '{ foo: T; }'. Two different types with this name exist, but they are unrelated.
!!! error TS2430:           Types of property 'foo' are incompatible.
!!! error TS2430:             Type 'T' is not assignable to type 'T'. Two different types with this name exist, but they are unrelated.
!!! error TS2430:               'T' could be instantiated with an arbitrary type which could be unrelated to 'T'.
!!! related TS2208 callSignatureAssignabilityInInheritance6.ts:18:11: This type parameter might need an `extends T` constraint.
        a11: <U>(x: { foo: T }, y: { foo: U; bar: U }) => Base; 
    }
    
    interface I9<T> extends A {
              ~~
!!! error TS2430: Interface 'I9<T>' incorrectly extends interface 'A'.
!!! error TS2430:   Types of property 'a16' are incompatible.
!!! error TS2430:     Type '(x: { a: T; b: T; }) => T[]' is not assignable to type '<T extends Base>(x: { a: T; b: T; }) => T[]'.
!!! error TS2430:       Types of parameters 'x' and 'x' are incompatible.
!!! error TS2430:         Type '{ a: T; b: T; }' is not assignable to type '{ a: T; b: T; }'. Two different types with this name exist, but they are unrelated.
!!! error TS2430:           Types of property 'a' are incompatible.
!!! error TS2430:             Type 'T' is not assignable to type 'T'. Two different types with this name exist, but they are unrelated.
!!! error TS2430:               'T' could be instantiated with an arbitrary type which could be unrelated to 'T'.
        a16: (x: { a: T; b: T }) => T[]; 
    }