==== tests/cases/conformance/classes/propertyMemberDeclarations/memberFunctionDeclarations/instanceMemberAssignsToClassPrototype.ts (1 errors) ====
    class C {
        foo() {
            C.prototype.foo = () => { }
        }
    
        bar(x: number): number {
            C.prototype.bar = () => { } // error
            ~~~~~~~~~~~~~~~
!!! Type '() => void' is not assignable to type '(x: number) => number':
!!!   Type 'void' is not assignable to type 'number'.
            C.prototype.bar = (x) => x; // ok
            C.prototype.bar = (x: number) => 1; // ok
            return 1;
        }
    }