Fix native static return typehint when entering class method

Author: ondrejmirtes

src/Analyser/MutatingScope.php

@@ -2595,7 +2595,7 @@ public function enterClassMethod(
 					return TemplateTypeHelper::toArgument($type);
 				}, $phpDocParameterTypes),
 				$this->getRealParameterDefaultValues($classMethod),
-				$this->getFunctionType($classMethod->returnType, $classMethod->returnType === null, false),
+				$this->transformStaticType($this->getFunctionType($classMethod->returnType, $classMethod->returnType === null, false)),
 				$phpDocReturnType !== null ? TemplateTypeHelper::toArgument($phpDocReturnType) : null,
 				$throwType,
 				$deprecatedDescription,
@@ -2608,6 +2608,25 @@ public function enterClassMethod(
 		);
 	}
 
+	private function transformStaticType(Type $type): Type
+	{
+		return TypeTraverser::map($type, function (Type $type, callable $traverse): Type {
+			if (!$this->isInClass()) {
+				return $type;
+			}
+			if ($type instanceof StaticType) {
+				$classReflection = $this->getClassReflection();
+				$changedType = $type->changeBaseClass($classReflection);
+				if ($classReflection->isFinal()) {
+					$changedType = $changedType->getStaticObjectType();
+				}
+				return $traverse($changedType);
+			}
+
+			return $traverse($type);
+		});
+	}
+
 	/**
 	 * @param Node\FunctionLike $functionLike
 	 * @return Type[]

tests/PHPStan/Rules/Methods/ReturnTypeRuleTest.php

@@ -477,4 +477,12 @@ public function testBug3118(): void
 		]);
 	}
 
+	public function testBug4795(): void
+	{
+		if (PHP_VERSION_ID < 80000 && !self::$useStaticReflectionProvider) {
+			$this->markTestSkipped('Test requires PHP 8.0');
+		}
+		$this->analyse([__DIR__ . '/data/bug-4795.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Methods/data/bug-4795.php

@@ -0,0 +1,47 @@
+<?php // lint >= 8.0
+
+namespace Bug4795;
+
+abstract class BaseDTO
+{
+
+	final protected static function create(): static
+	{
+		$class = static::class;
+
+		return new $class();
+	}
+
+	abstract public static function parse(): static;
+
+}
+
+final class ConcreteDTO extends BaseDTO
+{
+
+	public string $foo;
+
+	public static function parse(): static
+	{
+		$instance = self::create();
+
+		$instance->foo = 'bar';
+
+		return $instance;
+	}
+}
+
+class NonFinalConcreteDTO extends BaseDTO
+{
+
+	public string $foo;
+
+	public static function parse(): static
+	{
+		$instance = self::create();
+
+		$instance->foo = 'bar';
+
+		return $instance;
+	}
+}