Keep the expression result alive in the native ReturnHandler

tests/PHPStan/Analyser/ReturnedExprGetTypeRule.php

@@ -0,0 +1,38 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Analyser;
+
+use PhpParser\Node;
+use PhpParser\Node\Stmt\ClassMethod;
+use PhpParser\Node\Stmt\Return_;
+use PhpParser\NodeFinder;
+use PHPStan\Rules\Rule;
+
+/**
+ * Asks the type of a method's returned expression from the callback for the
+ * method itself, after the walk of the body is complete. The test only checks
+ * that this does not crash.
+ *
+ * @implements Rule<ClassMethod>
+ */
+class ReturnedExprGetTypeRule implements Rule
+{
+
+	public function getNodeType(): string
+	{
+		return ClassMethod::class;
+	}
+
+	public function processNode(Node $node, Scope $scope): array
+	{
+		$return = (new NodeFinder())->findFirstInstanceOf((array) $node->stmts, Return_::class);
+		if ($return === null || $return->expr === null) {
+			return [];
+		}
+
+		$scope->getType($return->expr);
+
+		return [];
+	}
+
+}

tests/PHPStan/Analyser/ReturnedExprGetTypeRuleTest.php

@@ -0,0 +1,26 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Analyser;
+
+use PHPStan\Rules\Rule;
+use PHPStan\Testing\RuleTestCase;
+use PHPUnit\Framework\Attributes\RequiresPhp;
+
+/**
+ * @extends RuleTestCase<ReturnedExprGetTypeRule>
+ */
+class ReturnedExprGetTypeRuleTest extends RuleTestCase
+{
+
+	protected function getRule(): Rule
+	{
+		return new ReturnedExprGetTypeRule();
+	}
+
+	#[RequiresPhp('>= 8.0.0')]
+	public function testRule(): void
+	{
+		$this->analyse([__DIR__ . '/data/returned-expr-get-type.php'], []);
+	}
+
+}

tests/PHPStan/Analyser/data/returned-expr-get-type.php

@@ -0,0 +1,27 @@
+<?php // lint >= 8.0
+
+declare(strict_types = 1);
+
+namespace ReturnedExprGetType;
+
+/** @template T */
+final class Bag {
+	/** @param list<T> $items */
+	public function __construct(private array $items) {}
+	/** @return list<T> */
+	public function all(): array { return $this->items; }
+}
+
+/**
+ * @template TReturnType
+ * @param callable(): TReturnType $callback
+ * @return TReturnType
+ */
+function once4(callable $callback) { return $callback(); }
+
+final class Box4 {
+	/** @return Bag<string> */
+	public function items(): Bag {
+		return once4(function (): Bag { return new Bag(['a']); });
+	}
+}

turbo-ext/src/ReturnHandler.cpp

@@ -79,6 +79,7 @@ class ReturnHandler
 		zval *throwPoints = &emptyArray;
 		zval *impurePoints = &emptyArray;
 		zval *dependencies = NULL;
+		zv::Val result;
 		zv::Val variableFlow;
 		expr = returnedExpr(stmt);
 		if (UNEXPECTED(expr == NULL)) return zv::Val();
@@ -96,7 +97,7 @@ class ReturnHandler
 				Z_TYPE_P(expectedReturnType.raw()) == IS_OBJECT ? expectedReturnType.raw() : NULL,
 				Z_TYPE_P(nativeExpectedReturnType.raw()) == IS_OBJECT ? nativeExpectedReturnType.raw() : NULL);
 			if (UNEXPECTED(expressionContext.isUndef())) return zv::Val();
-			zv::Val result = pt_node_scope_resolver_process_expr_node(nodeScopeResolver, stmt, expr, stmtScope.raw(), storage, nodeCallback, expressionContext.raw());
+			result = pt_node_scope_resolver_process_expr_node(nodeScopeResolver, stmt, expr, stmtScope.raw(), storage, nodeCallback, expressionContext.raw());
 			if (UNEXPECTED(result.isUndef())) return zv::Val();
 			dependencies = pt_expression_result_dependencies(result.raw(), dependenciesHold);
 			if (UNEXPECTED(dependencies == NULL)) return zv::Val();