tests/cases/compiler/functionCall8.ts(3,1): error TS2346: Supplied parameters do not match any signature of call target. tests/cases/compiler/functionCall8.ts(4,5): error TS2345: Argument of type 'number' is not assignable to parameter of type 'string'. ==== tests/cases/compiler/functionCall8.ts (2 errors) ==== function foo(a?:string){} foo('foo'); foo('foo', 'bar'); ~~~~~~~~~~~~~~~~~ !!! error TS2346: Supplied parameters do not match any signature of call target. foo(4); ~ !!! error TS2345: Argument of type 'number' is not assignable to parameter of type 'string'. foo();