From 635d2e9ca12e3557cd663aa2e7ef1e6cf9c51de2 Mon Sep 17 00:00:00 2001
From: Markus Staab <maggus.staab@googlemail.com>
Date: Sat, 29 Nov 2025 13:30:35 +0100
Subject: [PATCH] Implement BinaryMulHandler

---
 .../ExprHandler/BinaryMulHandler.php          | 53 +++++++++++++++++++
 .../InitializerExprTypeResolver.php           |  5 ++
 .../PHPStan/Analyser/Generator/data/gnsr.php  | 15 ++++++
 3 files changed, 73 insertions(+)
 create mode 100644 src/Analyser/Generator/ExprHandler/BinaryMulHandler.php

diff --git a/src/Analyser/Generator/ExprHandler/BinaryMulHandler.php b/src/Analyser/Generator/ExprHandler/BinaryMulHandler.php
new file mode 100644
index 0000000000..94197441fb
--- /dev/null
+++ b/src/Analyser/Generator/ExprHandler/BinaryMulHandler.php
@@ -0,0 +1,53 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Analyser\Generator\ExprHandler;
+
+use Generator;
+use PhpParser\Node\Expr;
+use PhpParser\Node\Stmt;
+use PHPStan\Analyser\ExpressionContext;
+use PHPStan\Analyser\Generator\ExprAnalysisRequest;
+use PHPStan\Analyser\Generator\ExprAnalysisResult;
+use PHPStan\Analyser\Generator\ExprHandler;
+use PHPStan\Analyser\Generator\GeneratorScope;
+use PHPStan\Analyser\SpecifiedTypes;
+use PHPStan\DependencyInjection\AutowiredService;
+use PHPStan\Reflection\InitializerExprTypeResolver;
+use function array_merge;
+
+/**
+ * @implements ExprHandler<Expr\BinaryOp\Mul>
+ */
+#[AutowiredService]
+final class BinaryMulHandler implements ExprHandler
+{
+
+	public function __construct(private InitializerExprTypeResolver $initializerExprTypeResolver)
+	{
+	}
+
+	public function supports(Expr $expr): bool
+	{
+		return $expr instanceof Expr\BinaryOp\Mul;
+	}
+
+	public function analyseExpr(Stmt $stmt, Expr $expr, GeneratorScope $scope, ExpressionContext $context, ?callable $alternativeNodeCallback): Generator
+	{
+		$leftResult = yield new ExprAnalysisRequest($stmt, $expr->left, $scope, $context, $alternativeNodeCallback);
+		$rightResult = yield new ExprAnalysisRequest($stmt, $expr->right, $leftResult->scope, $context, $alternativeNodeCallback);
+
+		return new ExprAnalysisResult(
+			$this->initializerExprTypeResolver->getMulTypeFromTypes($expr->left, $expr->right, $leftResult->type, $rightResult->type),
+			$this->initializerExprTypeResolver->getMulTypeFromTypes($expr->left, $expr->right, $leftResult->nativeType, $rightResult->nativeType),
+			$rightResult->scope,
+			hasYield: $leftResult->hasYield || $rightResult->hasYield,
+			isAlwaysTerminating: $leftResult->isAlwaysTerminating || $rightResult->isAlwaysTerminating,
+			throwPoints: array_merge($leftResult->throwPoints, $rightResult->throwPoints),
+			impurePoints: array_merge($leftResult->impurePoints, $rightResult->impurePoints),
+			specifiedTruthyTypes: new SpecifiedTypes(),
+			specifiedFalseyTypes: new SpecifiedTypes(),
+			specifiedNullTypes: new SpecifiedTypes(),
+		);
+	}
+
+}
diff --git a/src/Reflection/InitializerExprTypeResolver.php b/src/Reflection/InitializerExprTypeResolver.php
index e9175d7cff..8fc4c159cf 100644
--- a/src/Reflection/InitializerExprTypeResolver.php
+++ b/src/Reflection/InitializerExprTypeResolver.php
@@ -1574,6 +1574,11 @@ public function getMulType(Expr $left, Expr $right, callable $getTypeCallback):
 		$leftType = $getTypeCallback($left);
 		$rightType = $getTypeCallback($right);
 
+		return $this->getMulTypeFromTypes($left, $right, $leftType, $rightType);
+	}
+
+	public function getMulTypeFromTypes(Expr $left, Expr $right, Type $leftType, Type $rightType): Type
+	{
 		$leftTypes = $leftType->getConstantScalarTypes();
 		$rightTypes = $rightType->getConstantScalarTypes();
 		$leftTypesCount = count($leftTypes);
diff --git a/tests/PHPStan/Analyser/Generator/data/gnsr.php b/tests/PHPStan/Analyser/Generator/data/gnsr.php
index 723a07fc69..70b4828302 100644
--- a/tests/PHPStan/Analyser/Generator/data/gnsr.php
+++ b/tests/PHPStan/Analyser/Generator/data/gnsr.php
@@ -52,6 +52,21 @@ public function doMinus($a, $b, int $c, int $d): void
 		assertNativeType('int', $c - $d);
 	}
 
+	/**
+	 * @param int $a
+	 * @param int $b
+	 * @return void
+	 */
+	public function doMul($a, $b, int $c, int $d): void
+	{
+		assertType('int', $a * $b);
+		assertNativeType('(float|int)', $a * $b);
+		assertType('1', 1 * 1);
+		assertNativeType('1', 1 * 1);
+		assertType('int', $c * $d);
+		assertNativeType('int', $c * $d);
+	}
+
 }
 
 function (): void {