StringAlwaysAcceptingObjectWithToStringType is supertype of Stringable objects

Author: ondrejmirtes

src/Type/StringAlwaysAcceptingObjectWithToStringType.php

@@ -3,10 +3,36 @@
 namespace PHPStan\Type;
 
 use PHPStan\Reflection\ReflectionProviderStaticAccessor;
+use PHPStan\TrinaryLogic;
 
 class StringAlwaysAcceptingObjectWithToStringType extends StringType
 {
 
+	public function isSuperTypeOf(Type $type): TrinaryLogic
+	{
+		if ($type instanceof CompoundType) {
+			return $type->isSubTypeOf($this);
+		}
+
+		$thatClassNames = $type->getObjectClassNames();
+		if ($thatClassNames === []) {
+			return parent::isSuperTypeOf($type);
+		}
+
+		$result = TrinaryLogic::createNo();
+		$reflectionProvider = ReflectionProviderStaticAccessor::getInstance();
+		foreach ($thatClassNames as $thatClassName) {
+			if (!$reflectionProvider->hasClass($thatClassName)) {
+				return TrinaryLogic::createNo();
+			}
+
+			$typeClass = $reflectionProvider->getClass($thatClassName);
+			$result = $result->or(TrinaryLogic::createFromBoolean($typeClass->hasNativeMethod('__toString')));
+		}
+
+		return $result;
+	}
+
 	public function acceptsWithReason(Type $type, bool $strictTypes): AcceptsResult
 	{
 		$thatClassNames = $type->getObjectClassNames();

tests/PHPStan/Type/StringTypeTest.php

@@ -86,6 +86,11 @@ public function dataIsSuperTypeOf(): array
 				new GenericClassStringType(new ObjectType(stdClass::class)),
 				TrinaryLogic::createMaybe(),
 			],
+			[
+				new StringAlwaysAcceptingObjectWithToStringType(),
+				new ObjectType(ClassWithToString::class),
+				TrinaryLogic::createYes(),
+			],
 		];
 	}