tests/cases/conformance/statements/returnStatements/invalidReturnStatements.ts(2,17): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value or consist of a single 'throw' statement. tests/cases/conformance/statements/returnStatements/invalidReturnStatements.ts(3,17): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value or consist of a single 'throw' statement. tests/cases/conformance/statements/returnStatements/invalidReturnStatements.ts(4,17): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value or consist of a single 'throw' statement. tests/cases/conformance/statements/returnStatements/invalidReturnStatements.ts(5,17): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value or consist of a single 'throw' statement. tests/cases/conformance/statements/returnStatements/invalidReturnStatements.ts(16,29): error TS2322: Type '{ id: number; }' is not assignable to type 'D'. Property 'name' is missing in type '{ id: number; }'. tests/cases/conformance/statements/returnStatements/invalidReturnStatements.ts(18,29): error TS2322: Type 'C' is not assignable to type 'D'. Property 'name' is missing in type 'C'. ==== tests/cases/conformance/statements/returnStatements/invalidReturnStatements.ts (6 errors) ==== // all the following should be error function fn1(): number { } ~~~~~~ !!! error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value or consist of a single 'throw' statement. function fn2(): string { } ~~~~~~ !!! error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value or consist of a single 'throw' statement. function fn3(): boolean { } ~~~~~~~ !!! error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value or consist of a single 'throw' statement. function fn4(): Date { } ~~~~ !!! error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value or consist of a single 'throw' statement. function fn7(): any { } // should be valid: any includes void interface I { id: number } class C implements I { id: number; dispose() {} } class D extends C { name: string; } function fn10(): D { return { id: 12 }; } ~~~~~~~~~~ !!! error TS2322: Type '{ id: number; }' is not assignable to type 'D'. !!! error TS2322: Property 'name' is missing in type '{ id: number; }'. function fn11(): D { return new C(); } ~~~~~~~ !!! error TS2322: Type 'C' is not assignable to type 'D'. !!! error TS2322: Property 'name' is missing in type 'C'.