Merge pull request #1524 from staabm/trait

Support indirect `Stringable` interface via `__toString()` in trait

Author: Ocramius

src/Reflection/ReflectionClass.php

@@ -1315,7 +1315,12 @@ private function addStringableInterface(array $interfaces): array
             return $interfaces;
         }
 
-        foreach (array_keys($this->immediateMethods) as $immediateMethodName) {
+        $methods = $this->immediateMethods;
+        foreach ($this->getTraits() as $trait) {
+            $methods += $trait->immediateMethods;
+        }
+
+        foreach (array_keys($methods) as $immediateMethodName) {
             if (strtolower($immediateMethodName) === '__tostring') {
                 try {
                     $stringableInterfaceReflection = $this->reflector->reflectClass($stringableClassName);

test/unit/Reflection/ReflectionClassTest.php

@@ -2878,6 +2878,30 @@ public function __toString(): string
         self::assertSame(['Iterator', 'Traversable', 'Stringable'], $class->getInterfaceNames());
     }
 
+    public function testStringableViaTrait(): void
+    {
+        $php = <<<'PHP'
+            <?php
+
+            trait HasStringableTrait {
+                public function __toString(): string { return 'foo'; }
+            }
+
+            class ClassHasStringableTrait {
+            	use HasStringableTrait;
+            }
+        PHP;
+
+        $reflector = new DefaultReflector(new AggregateSourceLocator([
+            new StringSourceLocator($php, $this->astLocator),
+            BetterReflectionSingleton::instance()->sourceLocator(),
+        ]));
+
+        $class = $reflector->reflectClass('ClassHasStringableTrait');
+
+        self::assertSame(['Stringable'], $class->getInterfaceNames());
+    }
+
     /** @return list<array{0: string, 1: bool}> */
     public static function deprecatedProvider(): array
     {