tests/cases/compiler/declarationEmitDestructuringWithOptionalBindingParameters.ts(1,14): error TS2463: A binding pattern parameter cannot be optional in an implementation signature. tests/cases/compiler/declarationEmitDestructuringWithOptionalBindingParameters.ts(3,16): error TS2463: A binding pattern parameter cannot be optional in an implementation signature. ==== tests/cases/compiler/declarationEmitDestructuringWithOptionalBindingParameters.ts (2 errors) ==== function foo([x,y,z]?: [string, number, boolean]) { ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ !!! error TS2463: A binding pattern parameter cannot be optional in an implementation signature. } function foo1( { x, y, z }?: { x: string; y: number; z: boolean }) { ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ !!! error TS2463: A binding pattern parameter cannot be optional in an implementation signature. }