Add ThrowableReturnTypeExtension (phpstan#795)

conf/config.neon

@@ -1268,6 +1268,11 @@ services:
 		tags:
 			- phpstan.broker.dynamicFunctionReturnTypeExtension
 
+	-
+		class: PHPStan\Type\Php\ThrowableReturnTypeExtension
+		tags:
+			- phpstan.broker.dynamicMethodReturnTypeExtension
+
 	-
 		class: PHPStan\Type\Php\ParseUrlFunctionDynamicReturnTypeExtension
 		tags:

src/Type/Php/ThrowableReturnTypeExtension.php

@@ -0,0 +1,31 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Type\Php;
+
+use PhpParser\Node\Expr\MethodCall;
+use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\MethodReflection;
+use PHPStan\Type\BenevolentUnionType;
+use PHPStan\Type\IntegerType;
+use PHPStan\Type\StringType;
+use PHPStan\Type\Type;
+
+final class ThrowableReturnTypeExtension implements \PHPStan\Type\DynamicMethodReturnTypeExtension
+{
+
+	public function getClass(): string
+	{
+		return \Throwable::class;
+	}
+
+	public function isMethodSupported(MethodReflection $methodReflection): bool
+	{
+		return $methodReflection->getName() === 'getCode';
+	}
+
+	public function getTypeFromMethodCall(MethodReflection $methodReflection, MethodCall $methodCall, Scope $scope): Type
+	{
+		return new BenevolentUnionType([new IntegerType(), new StringType()]);
+	}
+
+}

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -530,6 +530,7 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-4743.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-5017.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-5992.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-6001.php');
 
 		if (PHP_VERSION_ID >= 70400) {
 			yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-5458.php');

tests/PHPStan/Analyser/data/bug-6001.php

@@ -0,0 +1,11 @@
+<?php declare(strict_types=1);
+
+namespace Bug6001;
+
+use function PHPStan\Testing\assertType;
+
+assertType('(int|string)', (new \Exception())->getCode());
+
+assertType('(int|string)', (new \RuntimeException())->getCode());
+
+assertType('(int|string)', (new \PDOException())->getCode());

tests/PHPStan/Analyser/data/generics.php

@@ -1400,7 +1400,7 @@ public function process($class): void {
 }
 
 function (\Throwable $e): void {
-	assertType('mixed', $e->getCode());
+	assertType('(int|string)', $e->getCode());
 };
 
 function (): void {