tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithCallSignatures2.ts(31,1): error TS2322: Type '() => number' is not assignable to type 'T'. Property 'f' is missing in type '() => number'. tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithCallSignatures2.ts(32,1): error TS2322: Type '(x: number) => string' is not assignable to type 'T'. Property 'f' is missing in type '(x: number) => string'. tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithCallSignatures2.ts(33,1): error TS2322: Type '() => number' is not assignable to type '{ f(x: number): void; }'. Property 'f' is missing in type '() => number'. tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithCallSignatures2.ts(34,1): error TS2322: Type '(x: number) => string' is not assignable to type '{ f(x: number): void; }'. Property 'f' is missing in type '(x: number) => string'. tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithCallSignatures2.ts(42,1): error TS2322: Type 'S2' is not assignable to type 'T'. Types of property 'f' are incompatible. Type '(x: string) => void' is not assignable to type '(x: number) => void'. Types of parameters 'x' and 'x' are incompatible. Type 'string' is not assignable to type 'number'. tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithCallSignatures2.ts(43,1): error TS2322: Type '{ f(x: string): void; }' is not assignable to type 'T'. Types of property 'f' are incompatible. Type '(x: string) => void' is not assignable to type '(x: number) => void'. Types of parameters 'x' and 'x' are incompatible. Type 'string' is not assignable to type 'number'. tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithCallSignatures2.ts(44,1): error TS2322: Type '(x: string) => number' is not assignable to type 'T'. Property 'f' is missing in type '(x: string) => number'. tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithCallSignatures2.ts(45,1): error TS2322: Type '(x: string) => string' is not assignable to type 'T'. Property 'f' is missing in type '(x: string) => string'. tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithCallSignatures2.ts(46,1): error TS2322: Type 'S2' is not assignable to type '{ f(x: number): void; }'. Types of property 'f' are incompatible. Type '(x: string) => void' is not assignable to type '(x: number) => void'. Types of parameters 'x' and 'x' are incompatible. Type 'string' is not assignable to type 'number'. tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithCallSignatures2.ts(47,1): error TS2322: Type '{ f(x: string): void; }' is not assignable to type '{ f(x: number): void; }'. Types of property 'f' are incompatible. Type '(x: string) => void' is not assignable to type '(x: number) => void'. Types of parameters 'x' and 'x' are incompatible. Type 'string' is not assignable to type 'number'. tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithCallSignatures2.ts(48,1): error TS2322: Type '(x: string) => number' is not assignable to type '{ f(x: number): void; }'. Property 'f' is missing in type '(x: string) => number'. tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithCallSignatures2.ts(49,1): error TS2322: Type '(x: string) => string' is not assignable to type '{ f(x: number): void; }'. Property 'f' is missing in type '(x: string) => string'. ==== tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithCallSignatures2.ts (12 errors) ==== // void returning call signatures can be assigned a non-void returning call signature that otherwise matches interface T { f(x: number): void; } var t: T; var a: { f(x: number): void }; t = a; a = t; interface S { f(x: number): string; } var s: S; var a2: { f(x: number): string }; t = s; t = a2; a = s; a = a2; t = { f: () => 1 }; t = { f: (x:T) => 1 }; t = { f: function f() { return 1 } }; t = { f(x: number) { return ''; } } a = { f: () => 1 } a = { f: (x: T) => 1 }; a = { f: function (x: number) { return ''; } } // errors t = () => 1; ~ !!! error TS2322: Type '() => number' is not assignable to type 'T'. !!! error TS2322: Property 'f' is missing in type '() => number'. t = function (x: number) { return ''; } ~ !!! error TS2322: Type '(x: number) => string' is not assignable to type 'T'. !!! error TS2322: Property 'f' is missing in type '(x: number) => string'. a = () => 1; ~ !!! error TS2322: Type '() => number' is not assignable to type '{ f(x: number): void; }'. !!! error TS2322: Property 'f' is missing in type '() => number'. a = function (x: number) { return ''; } ~ !!! error TS2322: Type '(x: number) => string' is not assignable to type '{ f(x: number): void; }'. !!! error TS2322: Property 'f' is missing in type '(x: number) => string'. interface S2 { f(x: string): void; } var s2: S2; var a3: { f(x: string): void }; // these are errors t = s2; ~ !!! error TS2322: Type 'S2' is not assignable to type 'T'. !!! error TS2322: Types of property 'f' are incompatible. !!! error TS2322: Type '(x: string) => void' is not assignable to type '(x: number) => void'. !!! error TS2322: Types of parameters 'x' and 'x' are incompatible. !!! error TS2322: Type 'string' is not assignable to type 'number'. t = a3; ~ !!! error TS2322: Type '{ f(x: string): void; }' is not assignable to type 'T'. !!! error TS2322: Types of property 'f' are incompatible. !!! error TS2322: Type '(x: string) => void' is not assignable to type '(x: number) => void'. !!! error TS2322: Types of parameters 'x' and 'x' are incompatible. !!! error TS2322: Type 'string' is not assignable to type 'number'. t = (x: string) => 1; ~ !!! error TS2322: Type '(x: string) => number' is not assignable to type 'T'. !!! error TS2322: Property 'f' is missing in type '(x: string) => number'. t = function (x: string) { return ''; } ~ !!! error TS2322: Type '(x: string) => string' is not assignable to type 'T'. !!! error TS2322: Property 'f' is missing in type '(x: string) => string'. a = s2; ~ !!! error TS2322: Type 'S2' is not assignable to type '{ f(x: number): void; }'. !!! error TS2322: Types of property 'f' are incompatible. !!! error TS2322: Type '(x: string) => void' is not assignable to type '(x: number) => void'. !!! error TS2322: Types of parameters 'x' and 'x' are incompatible. !!! error TS2322: Type 'string' is not assignable to type 'number'. a = a3; ~ !!! error TS2322: Type '{ f(x: string): void; }' is not assignable to type '{ f(x: number): void; }'. !!! error TS2322: Types of property 'f' are incompatible. !!! error TS2322: Type '(x: string) => void' is not assignable to type '(x: number) => void'. !!! error TS2322: Types of parameters 'x' and 'x' are incompatible. !!! error TS2322: Type 'string' is not assignable to type 'number'. a = (x: string) => 1; ~ !!! error TS2322: Type '(x: string) => number' is not assignable to type '{ f(x: number): void; }'. !!! error TS2322: Property 'f' is missing in type '(x: string) => number'. a = function (x: string) { return ''; } ~ !!! error TS2322: Type '(x: string) => string' is not assignable to type '{ f(x: number): void; }'. !!! error TS2322: Property 'f' is missing in type '(x: string) => string'.