genericClassWithFunctionTypedMemberArguments.ts(7,22): error TS2345: Argument of type 'null' is not assignable to parameter of type 'T'.
  'T' could be instantiated with an arbitrary type which could be unrelated to 'null'.
genericClassWithFunctionTypedMemberArguments.ts(18,22): error TS2345: Argument of type 'null' is not assignable to parameter of type 'T'.
  'T' could be instantiated with an arbitrary type which could be unrelated to 'null'.
genericClassWithFunctionTypedMemberArguments.ts(57,26): error TS2345: Argument of type 'number' is not assignable to parameter of type 'T'.
  'T' could be instantiated with an arbitrary type which could be unrelated to 'number'.
genericClassWithFunctionTypedMemberArguments.ts(60,27): error TS2345: Argument of type 'number' is not assignable to parameter of type 'T'.
  'T' could be instantiated with an arbitrary type which could be unrelated to 'number'.
genericClassWithFunctionTypedMemberArguments.ts(61,28): error TS2345: Argument of type 'number' is not assignable to parameter of type 'T'.
  'T' could be instantiated with an arbitrary type which could be unrelated to 'number'.
genericClassWithFunctionTypedMemberArguments.ts(62,30): error TS2345: Argument of type '(a: number) => string' is not assignable to parameter of type '(a: number) => 1'.
  Type 'string' is not assignable to type '1'.


==== genericClassWithFunctionTypedMemberArguments.ts (6 errors) ====
    // Generic functions used as arguments for function typed parameters are not used to make inferences from
    // Using function arguments, no errors expected
    
    namespace ImmediatelyFix {
        class C<T> {
            foo<T>(x: (a: T) => T) {
                return x(null);
                         ~~~~
!!! error TS2345: Argument of type 'null' is not assignable to parameter of type 'T'.
!!! error TS2345:   'T' could be instantiated with an arbitrary type which could be unrelated to 'null'.
            }
        }
    
        var c = new C<number>();
        var r = c.foo(<U>(x: U) => ''); // {}
        var r2 = c.foo<string>(<U>(x: U) => ''); // string 
        var r3 = c.foo(x => ''); // {}
    
        class C2<T> {
            foo(x: (a: T) => T) {
                return x(null);
                         ~~~~
!!! error TS2345: Argument of type 'null' is not assignable to parameter of type 'T'.
!!! error TS2345:   'T' could be instantiated with an arbitrary type which could be unrelated to 'null'.
            }
        }
    
        var c2 = new C2<number>();
        var ra = c2.foo(<U>(x: U) => 1); // number
        var r3a = c2.foo(x => 1); // number
    }
    
    namespace WithCandidates {
        class C<T> {
            foo2<T, U>(x: T, cb: (a: T) => U) {
                return cb(x);
            }
        }
    
        declare var c: C<number>;
        var r4 = c.foo2(1, function <Z>(a: Z) { return '' }); // string, contextual signature instantiation is applied to generic functions
        var r5 = c.foo2(1, (a) => ''); // string
        var r6 = c.foo2<string, number>('', <Z>(a: Z) => 1); // number
    
        class C2<T, U> {
            foo3(x: T, cb: (a: T) => U, y: U) {
                return cb(x);
            }
        }
    
        declare var c2: C2<number, string>;
        var r7 = c2.foo3(1, <Z>(a: Z) => '', ''); // string
        var r8 = c2.foo3(1, function (a) { return '' }, ''); // string
    
        class C3<T, U> {
            foo3<T,U>(x: T, cb: (a: T) => U, y: U) {
                return cb(x);
            }
        }
        declare var c3: C3<number, string>;
    
        function other<T, U>(t: T, u: U) {
            var r10 = c.foo2(1, (x: T) => ''); // error
                             ~
!!! error TS2345: Argument of type 'number' is not assignable to parameter of type 'T'.
!!! error TS2345:   'T' could be instantiated with an arbitrary type which could be unrelated to 'number'.
            var r10 = c.foo2(1, (x) => ''); // string
    
            var r11 = c3.foo3(1, (x: T) => '', ''); // error
                              ~
!!! error TS2345: Argument of type 'number' is not assignable to parameter of type 'T'.
!!! error TS2345:   'T' could be instantiated with an arbitrary type which could be unrelated to 'number'.
            var r11b = c3.foo3(1, (x: T) => '', 1); // error
                               ~
!!! error TS2345: Argument of type 'number' is not assignable to parameter of type 'T'.
!!! error TS2345:   'T' could be instantiated with an arbitrary type which could be unrelated to 'number'.
            var r12 = c3.foo3(1, function (a) { return '' }, 1); // error
                                 ~~~~~~~~
!!! error TS2345: Argument of type '(a: number) => string' is not assignable to parameter of type '(a: number) => 1'.
!!! error TS2345:   Type 'string' is not assignable to type '1'.
        }
    }