fix: props are not of type Comparable (#149)

Author: felangel

lib/src/equatable_utils.dart

@@ -1,5 +1,3 @@
-import 'dart:collection';
-
 import 'package:collection/collection.dart';
 import 'package:equatable/equatable.dart';
 
@@ -48,10 +46,8 @@ int _combine(int hash, dynamic object) {
     });
     return hash;
   }
-  if (object is Set && object is! SplayTreeSet) {
-    // this is needed to have a consistent iteration order so that the produced
-    // hash is consistent independently of the Set insertion order
-    object = SplayTreeSet<dynamic>.from(object);
+  if (object is Set) {
+    object = object.sorted(((dynamic a, dynamic b) => a.hashCode - b.hashCode));
   }
   if (object is Iterable) {
     for (final value in object) {

test/equatable_test.dart

@@ -1000,6 +1000,17 @@ void main() {
         expect(instanceA != instanceB, true);
         expect(instanceA.hashCode != instanceB.hashCode, true);
       });
+
+      test('should support non-comparable types', () {
+        final instanceA = SimpleEquatable<Set<Object>>(
+          Set.from(<Object>[Object()]),
+        );
+        final instanceB = SimpleEquatable<Set<Object>>(
+          Set.from(<Object>[Object()]),
+        );
+        expect(instanceA == instanceB, false);
+        expect(instanceA.hashCode == instanceB.hashCode, false);
+      });
     });
   });