get_defined_vars() return type contains know variables

Author: MartinMystikJonas

conf/config.neon

@@ -1427,6 +1427,11 @@ services:
 tags:
 - phpstan.broker.dynamicFunctionReturnTypeExtension
 
+-
+class: PHPStan\Type\Php\GetDefinedVarsFunctionReturnTypeExtension
+tags:
+- phpstan.broker.dynamicFunctionReturnTypeExtension
+
 -
 class: PHPStan\Type\Php\GetParentClassDynamicFunctionReturnTypeExtension
 tags:

src/Type/Php/GetDefinedVarsFunctionReturnTypeExtension.php

@@ -0,0 +1,52 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Type\Php;
+
+use PhpParser\Node\Expr\FuncCall;
+use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\FunctionReflection;
+use PHPStan\Type\ArrayType;
+use PHPStan\Type\Constant\ConstantArrayType;
+use PHPStan\Type\Constant\ConstantStringType;
+use PHPStan\Type\DynamicFunctionReturnTypeExtension;
+use PHPStan\Type\MixedType;
+use PHPStan\Type\StringType;
+use PHPStan\Type\Type;
+
+// based on code by @ruudk
+final class GetDefinedVarsFunctionReturnTypeExtension implements DynamicFunctionReturnTypeExtension
+{
+
+public function isFunctionSupported(FunctionReflection $functionReflection): bool
+{
+return $functionReflection->getName() === 'get_defined_vars';
+}
+
+public function getTypeFromFunctionCall(FunctionReflection $functionReflection, FuncCall $functionCall, Scope $scope): Type
+{
+if ($scope->canAnyVariableExist()) {
+return new ArrayType(
+new StringType(),
+new MixedType(),
+);
+}
+
+$variables = \array_values(\array_filter(
+$scope->getDefinedVariables(),
+static fn ($variable) => $variable !== 'this',
+));
+
+$keys = \array_map(
+static fn ($variable) => new ConstantStringType($variable),
+$variables,
+);
+
+$values = \array_map(
+static fn ($variable) => $scope->getVariableType($variable),
+$variables,
+);
+
+return new ConstantArrayType($keys, $values);
+}
+
+}

tests/PHPStan/Analyser/nsrt/get-defined-vars.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace GetDefinedVars;
+
+use function PHPStan\Testing\assertType;
+
+function doFoo(int $param) {
+$local = "foo";
+assertType('array{param: int, local: \'foo\'}', get_defined_vars());
+assertType('array{\'param\', \'local\'}', array_keys(get_defined_vars()));
+}