TASK: Ensure that EnumType instances are considered equivalents of themselves

Author: grebaldi

src/TypeSystem/Type/EnumType/EnumType.php

@@ -40,6 +40,6 @@ enumName: $enumDeclarationNode->enumName
 
     public function is(TypeInterface $other): bool
     {
-        return false;
+        return $other === $this;
     }
 }

test/Unit/TypeSystem/Type/EnumType/EnumTypeTest.php

@@ -57,4 +57,20 @@ public function providesNameOfTheEnum(): void
 
         $this->assertEquals('SomeEnum', $enumType->enumName);
     }
+
+    /**
+     * @test
+     * @return void
+     */
+    public function isEquivalentToItself(): void
+    {
+        $enumDeclarationNode = EnumDeclarationNode::fromString(
+            'enum SomeEnum {}'
+        );
+        $enumType = EnumType::fromEnumDeclarationNode(
+            $enumDeclarationNode
+        );
+
+        $this->assertTrue($enumType->is($enumType));
+    }
 }