MethodInfo hashCode issue

[BladeWise]

The current implementation of MethodInfo.hashCode returns the same value for overloaded methods.

As an example, below code

var abs1 = Type.of(Math.class).getMethod("abs", Types.Integer);
var abs2 = Type.of(Math.class).getMethod("abs", Types.Long);
String.format("%s vs %s:\nAre equal? %s\nHave same hashCode? %s", abs1, abs2, abs1.equals(abs2), abs1.hashCode() == abs2.hashCode());

will print

public static int abs(int) vs public static long abs(long):
Are equal? false
Have same hashCode? true

This means that all hash-based collections will never store overloaded methods together, only the last added one.

I noticed that some MemberInfo-derived classes override isEquivalentTo, without touching hashCode.
I suppose that all classes overriding IsEquivalentTo, should override hashCode accordingly.

[mstrobel]

Thanks for the bug report!

for (MemberInfo m : Type.of(Math.class).findMembers(MemberType.methodsOnly(), BindingFlags.AllStatic, Type.FilterName, "abs")) {
    System.out.printf("%s = %d%n", m.getBriefDescription(), m.hashCode());
}

now yields

int abs(int) = -2086594591
double abs(double) = -2086575465
float abs(float) = -2086573285
long abs(long) = -2086594525