Fix infinite recursion

src/Type/ObjectType.php

@@ -656,7 +656,11 @@ public function getIterableKeyType(): Type
 		}
 
 		if ($this->isInstanceOf(\Iterator::class)->yes()) {
-			return ParametersAcceptorSelector::selectSingle($this->getMethod('key', new OutOfClassScope())->getVariants())->getReturnType();
+			return RecursionGuard::run($this, function (): Type {
+				return ParametersAcceptorSelector::selectSingle(
+					$this->getMethod('key', new OutOfClassScope())->getVariants()
+				)->getReturnType();
+			});
 		}
 
 		if ($this->isInstanceOf(\IteratorAggregate::class)->yes()) {
@@ -685,9 +689,11 @@ public function getIterableKeyType(): Type
 	public function getIterableValueType(): Type
 	{
 		if ($this->isInstanceOf(\Iterator::class)->yes()) {
-			return ParametersAcceptorSelector::selectSingle(
-				$this->getMethod('current', new OutOfClassScope())->getVariants()
-			)->getReturnType();
+			return RecursionGuard::run($this, function (): Type {
+				return ParametersAcceptorSelector::selectSingle(
+					$this->getMethod('current', new OutOfClassScope())->getVariants()
+				)->getReturnType();
+			});
 		}
 
 		if ($this->isInstanceOf(\IteratorAggregate::class)->yes()) {

tests/PHPStan/Analyser/AnalyserIntegrationTest.php

@@ -410,6 +410,18 @@ public function testBug4734(): void
 		$this->assertSame('Access to an undefined property Bug4734\Foo::$httpMethodParameterOverride4.', $errors[1]->getMessage());
 	}
 
+	public function testBug5231(): void
+	{
+		$errors = $this->runAnalyse(__DIR__ . '/data/bug-5231.php');
+		$this->assertCount(5, $errors);
+	}
+
+	public function testBug5231Two(): void
+	{
+		$errors = $this->runAnalyse(__DIR__ . '/data/bug-5231_2.php');
+		$this->assertCount(1, $errors);
+	}
+
 	/**
 	 * @param string $file
 	 * @return \PHPStan\Analyser\Error[]

tests/PHPStan/Analyser/data/bug-5231.php

@@ -0,0 +1,78 @@
+<?php
+
+namespace Bug5231;
+
+class SomeClass
+{
+
+}
+
+// class with bug
+
+/**
+ *     annotation must be exists:
+ * @method SomeClass[]|SomeParentCollection getSorted()
+ */
+class SomeParentCollection implements \Iterator
+{
+	/** @var SomeClass[] */
+	protected $collection;
+
+	public function findByName(string $name): ?SomeClass
+	{
+		foreach ($this->collection as $item) {
+			if ((string)$item === $name) {
+				return $item;
+			}
+		}
+
+		return null;
+	}
+
+	// must be exists!
+	public function existsByKey(string $name): bool
+	{
+		return $this->findByName($name) !== null;
+	}
+
+	public function getSorted(callable $comparator): self
+	{
+		$sortedCollection = $this->collection;
+		usort($sortedCollection, $comparator);
+
+		$filtered = array_values($sortedCollection);
+
+		return new static(...$filtered);
+	}
+
+	public function rewind(): void
+	{
+		reset($this->collection);
+	}
+
+	public function current()
+	{
+		return current($this->collection);
+	}
+
+	/**
+	 * @return bool|float|int|string|null
+	 */
+	public function key()
+	{
+		return key($this->collection);
+	}
+
+	/**
+	 * @return mixed|void
+	 */
+	public function next()
+	{
+		return next($this->collection);
+	}
+
+	public function valid(): bool
+	{
+		return isset($this->collection[key($this->collection)]);
+	}
+}

tests/PHPStan/Analyser/data/bug-5231_2.php

@@ -0,0 +1,78 @@
+<?php
+
+namespace Bug5231Two;
+
+class SomeClass
+{
+
+}
+
+// class with bug
+
+/**
+ *     annotation must be exists:
+ * @method SomeClass[]|SomeParentCollection getSorted()
+ */
+class SomeParentCollection implements Iterator
+{
+	/** @var SomeClass[] */
+	protected $collection;
+
+	public function findByName(string $name): ?SomeClass
+	{
+		foreach ($this->collection as $item) {
+			if ((string)$item === $name) {
+				return $item;
+			}
+		}
+
+		return null;
+	}
+
+	// must be exists!
+	public function existsByKey(string $name): bool
+	{
+		return $this->findByName($name) !== null;
+	}
+
+	public function getSorted(callable $comparator): self
+	{
+		$sortedCollection = $this->collection;
+		usort($sortedCollection, $comparator);
+
+		$filtered = array_values($sortedCollection);
+
+		return new static(...$filtered);
+	}
+
+	public function rewind(): void
+	{
+		reset($this->collection);
+	}
+
+	public function current()
+	{
+		return current($this->collection);
+	}
+
+	/**
+	 * @return bool|float|int|string|null
+	 */
+	public function key()
+	{
+		return key($this->collection);
+	}
+
+	/**
+	 * @return mixed|void
+	 */
+	public function next()
+	{
+		return next($this->collection);
+	}
+
+	public function valid(): bool
+	{
+		return isset($this->collection[key($this->collection)]);
+	}
+}