==== tests/cases/compiler/optionalParamAssignmentCompat.ts (1 errors) ====
    interface I1 {
        (p1: number, p2: string): void;
    }
    interface I2 {
        p1: I1;
        m1(p1?: string): I1;
    }
    var i2: I2;
    var c: I1 = i2.p1; // should be ok
    var d: I1 = i2.m1; // should error
        ~
!!! Type '(p1?: string) => I1' is not assignable to type 'I1':
!!!   Types of parameters 'p1' and 'p1' are incompatible:
!!!     Type 'string' is not assignable to type 'number'.