TASK: UnionType RequiresAtLeastOneMember

Author: mhsdesign

src/TypeSystem/Type/UnionType/UnionType.php

@@ -37,16 +37,14 @@ final class UnionType implements TypeInterface, \IteratorAggregate, \Countable
 
     private function __construct(TypeInterface ...$members)
     {
-        if (count($members) < 1) {
-            throw new \Exception('UnionType can only hold more than one different members');
-        }
+        assert(count($members) > 1, 'UnionType must hold at least two different members');
         $this->members = $members;
     }
 
-    public static function of(TypeInterface ...$members): TypeInterface
+    public static function of(TypeInterface $firstMember, TypeInterface ...$members): TypeInterface
     {
         $uniqueMembers = [];
-        foreach ($members as $member) {
+        foreach ([$firstMember, ...$members] as $member) {
             foreach ($uniqueMembers as $uniqueMember) {
                 if ($member->is($uniqueMember)) {
                     continue 2;
@@ -82,9 +80,6 @@ public function withoutNull(): TypeInterface
             }
             $nonNullMembers[] = $member;
         }
-        if (count($nonNullMembers) === 1) {
-            return $nonNullMembers[0];
-        }
         return self::of(...$nonNullMembers);
     }
 

test/Unit/TypeSystem/Type/UnionType/UnionTypeTest.php

@@ -30,6 +30,16 @@
 
 final class UnionTypeTest extends TestCase
 {
+    /**
+     * @test
+     */
+    public function unionRequiresAtLeastOneMember(): void
+    {
+        $this->expectException(\TypeError::class);
+        /** @phpstan-ignore-next-line */
+        UnionType::of();
+    }
+
     /**
      * @test
      */