Regression tests

Closes phpstan/phpstan#3608
Closes phpstan/phpstan#3669
Closes phpstan/phpstan#3920
Closes phpstan/phpstan#3261
Closes phpstan/phpstan#4289
Closes phpstan/phpstan#2568

tests/PHPStan/Rules/Functions/ArrowFunctionReturnTypeRuleTest.php

@@ -41,4 +41,13 @@ public function testRule(): void
 		]);
 	}
 
+	public function testBug3261(): void
+	{
+		if (!self::$useStaticReflectionProvider && PHP_VERSION_ID < 70400) {
+			$this->markTestSkipped('Test requires PHP 7.4.');
+		}
+
+		$this->analyse([__DIR__ . '/data/bug-3261.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php

@@ -519,4 +519,14 @@ public function testBug2846(): void
 		$this->analyse([__DIR__ . '/data/bug-2846.php'], []);
 	}
 
+	public function testBug3608(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-3608.php'], []);
+	}
+
+	public function testBug3920(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-3920.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Functions/ReturnTypeRuleTest.php

@@ -83,4 +83,10 @@ public function testIsGenerator(): void
 		$this->analyse([__DIR__ . '/data/is-generator.php'], []);
 	}
 
+	public function testBug2568(): void
+	{
+		require_once __DIR__ . '/data/bug-2568.php';
+		$this->analyse([__DIR__ . '/data/bug-2568.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Functions/data/bug-2568.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace Bug2568;
+
+/**
+ * @template T
+ *
+ * @param array<T, mixed> $arr
+ * @return array<int, T>
+ */
+function my_array_keys($arr) {
+	return array_keys($arr);
+}

tests/PHPStan/Rules/Functions/data/bug-3261.php

@@ -0,0 +1,20 @@
+<?php // lint >= 7.4
+
+namespace Bug3261;
+
+class A
+{
+}
+
+class B extends A {}
+
+function (): void {
+	/** @var A[] $a */
+	$a = [];
+
+	array_filter(
+		$a,
+		fn (A $a) => $a instanceof B
+	);
+
+};

tests/PHPStan/Rules/Functions/data/bug-3608.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace Bug3608;
+
+interface IHost
+{
+	/** @return IHost[] * */
+	public static function getArray();
+}
+
+class MyHost implements IHost
+{
+	public static function getArray()
+	{
+		return [new self()];
+	}
+}
+
+class HelloWorld
+{
+	/**
+	 * @param class-string<IHost> $name
+	 **/
+	public function getConfig(string $name): void
+	{
+		call_user_func([$name, 'getArray']);
+
+	}
+}

tests/PHPStan/Rules/Functions/data/bug-3920.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace Bug3920;
+
+class HelloWorld
+{
+	/**
+	 * @return class-string<Two>
+	 */
+	public function sayHello(string $a)
+	{
+
+		$arr = [
+			'a' => Two::class,
+			'c' => Two::class,
+		];
+		return $arr[$a];
+	}
+
+	public function sayType(): void
+	{
+		call_user_func([One::class, 'isType']);
+		call_user_func([Two::class, 'isType']);
+		$class = $this->sayHello('a');
+		$type = $class::isType();
+		$callable = [$class, 'isType'];
+		call_user_func($callable);
+		if (is_callable($callable)) {
+			call_user_func($callable);
+		}
+	}
+}
+
+class One {
+	public static function isType(): bool
+	{
+		return true;
+	}
+}
+class Two extends One {
+
+}
+class Three {}

tests/PHPStan/Rules/Missing/MissingReturnRuleTest.php

@@ -131,4 +131,12 @@ public function testMissingMixedReturnInEmptyBody(): void
 		]);
 	}
 
+	public function testBug3669(): void
+	{
+		$this->checkExplicitMixedMissingReturn = true;
+
+		require_once __DIR__ . '/data/bug-3669.php';
+		$this->analyse([__DIR__ . '/data/bug-3669.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Missing/data/bug-3669.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace Bug3669;
+
+function foo(): \Generator
+{
+	while ($bar = yield 'foo') {
+	}
+}
+
+function bar($m): \Generator
+{
+	while ($bar = yield $m) {
+	}
+}

tests/PHPStan/Rules/Variables/UnsetRuleTest.php

@@ -53,4 +53,9 @@ public function testBug2752(): void
 		$this->analyse([__DIR__ . '/data/bug-2752.php'], []);
 	}
 
+	public function testBug4289(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-4289.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Variables/data/bug-4289.php

@@ -0,0 +1,28 @@
+<?php declare(strict_types = 1);
+
+namespace Bug4289;
+
+class BaseClass
+{
+	protected array $fields = [];
+
+	function populateFields(): void
+	{
+		$this->fields = [
+			'foo' => 'bar',
+			'some' => 'what',
+		];
+	}
+}
+
+class ChildClass extends BaseClass
+{
+	public function populateFields(): void
+	{
+		if (empty($this->fields)) {
+			parent::populateFields();
+
+			unset($this->fields['foo']);
+		}
+	}
+}