return true
	case Array:
		tt := (*arrayType)(unsafe.Pointer(t))
		return needKeyUpdate(tt.Elem)
	case Struct:
		tt := (*structType)(unsafe.Pointer(t))
		for _, f := range tt.Fields {
			if needKeyUpdate(f.Typ) {
				return true
			}
		}
		return false
	default:
		// Func, Map, Slice, Invalid
		panic("needKeyUpdate called on non-key type " + stringFor(t))
	}
}

		dst.tophash[pos] = src.tophash[i]
		if t.IndirectKey() {
			srcK = *(*unsafe.Pointer)(srcK)
			if t.NeedKeyUpdate() {
				kStore := newobject(t.Key)
				typedmemmove(t.Key, kStore, srcK)
				srcK = kStore
			}
			// Note: if NeedKeyUpdate is false, then the memory
			// used to store the key is immutable, so we can share
			// it between the original map and its clone.

	return mt.Flags&2 != 0
}
func (mt *MapType) ReflexiveKey() bool { // true if k==k for all keys
	return mt.Flags&4 != 0
}
func (mt *MapType) NeedKeyUpdate() bool { // true if we need to update key on an overwrite
	return mt.Flags&8 != 0
}
func (mt *MapType) HashMightPanic() bool { // true if hash function might panic
	return mt.Flags&16 != 0
}