From 7c587ab5dac77ae67df52475d472dc832c9762c4 Mon Sep 17 00:00:00 2001
From: Martin Herndl <martin@herndl.org>
Date: Fri, 18 Oct 2024 22:04:10 +0200
Subject: [PATCH] Only use last for condition to filter scope

---
 src/Analyser/NodeScopeResolver.php            | 21 ++++++++++++-------
 .../PHPStan/Analyser/nsrt/for-loop-i-type.php |  8 +++++++
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/src/Analyser/NodeScopeResolver.php b/src/Analyser/NodeScopeResolver.php
index 969d0be6b4..054ec1a2f9 100644
--- a/src/Analyser/NodeScopeResolver.php
+++ b/src/Analyser/NodeScopeResolver.php
@@ -1314,13 +1314,18 @@ private function processStmtNode(
 
 			$bodyScope = $initScope;
 			$isIterableAtLeastOnce = TrinaryLogic::createYes();
+			$lastCondExpr = $stmt->cond[count($stmt->cond) - 1] ?? null;
 			foreach ($stmt->cond as $condExpr) {
 				$condResult = $this->processExprNode($stmt, $condExpr, $bodyScope, static function (): void {
 				}, ExpressionContext::createDeep());
 				$initScope = $condResult->getScope();
 				$condResultScope = $condResult->getScope();
-				$condTruthiness = ($this->treatPhpDocTypesAsCertain ? $condResultScope->getType($condExpr) : $condResultScope->getNativeType($condExpr))->toBoolean();
-				$isIterableAtLeastOnce = $isIterableAtLeastOnce->and($condTruthiness->isTrue());
+
+				if ($condExpr === $lastCondExpr) {
+					$condTruthiness = ($this->treatPhpDocTypesAsCertain ? $condResultScope->getType($condExpr) : $condResultScope->getNativeType($condExpr))->toBoolean();
+					$isIterableAtLeastOnce = $isIterableAtLeastOnce->and($condTruthiness->isTrue());
+				}
+
 				$hasYield = $hasYield || $condResult->hasYield();
 				$throwPoints = array_merge($throwPoints, $condResult->getThrowPoints());
 				$impurePoints = array_merge($impurePoints, $condResult->getImpurePoints());
@@ -1332,8 +1337,8 @@ private function processStmtNode(
 				do {
 					$prevScope = $bodyScope;
 					$bodyScope = $bodyScope->mergeWith($initScope);
-					foreach ($stmt->cond as $condExpr) {
-						$bodyScope = $this->processExprNode($stmt, $condExpr, $bodyScope, static function (): void {
+					if ($lastCondExpr !== null) {
+						$bodyScope = $this->processExprNode($stmt, $lastCondExpr, $bodyScope, static function (): void {
 						}, ExpressionContext::createDeep())->getTruthyScope();
 					}
 					$bodyScopeResult = $this->processStmtNodes($stmt, $stmt->stmts, $bodyScope, static function (): void {
@@ -1363,8 +1368,8 @@ private function processStmtNode(
 			}
 
 			$bodyScope = $bodyScope->mergeWith($initScope);
-			foreach ($stmt->cond as $condExpr) {
-				$bodyScope = $this->processExprNode($stmt, $condExpr, $bodyScope, $nodeCallback, ExpressionContext::createDeep())->getTruthyScope();
+			if ($lastCondExpr !== null) {
+				$bodyScope = $this->processExprNode($stmt, $lastCondExpr, $bodyScope, $nodeCallback, ExpressionContext::createDeep())->getTruthyScope();
 			}
 
 			$finalScopeResult = $this->processStmtNodes($stmt, $stmt->stmts, $bodyScope, $nodeCallback, $context)->filterOutLoopExitPoints();
@@ -1378,8 +1383,8 @@ private function processStmtNode(
 				$loopScope = $this->processExprNode($stmt, $loopExpr, $loopScope, $nodeCallback, ExpressionContext::createTopLevel())->getScope();
 			}
 			$finalScope = $finalScope->generalizeWith($loopScope);
-			foreach ($stmt->cond as $condExpr) {
-				$finalScope = $finalScope->filterByFalseyValue($condExpr);
+			if ($lastCondExpr !== null) {
+				$finalScope = $finalScope->filterByFalseyValue($lastCondExpr);
 			}
 
 			foreach ($finalScopeResult->getExitPointsByType(Break_::class) as $breakExitPoint) {
diff --git a/tests/PHPStan/Analyser/nsrt/for-loop-i-type.php b/tests/PHPStan/Analyser/nsrt/for-loop-i-type.php
index 011d15d6c7..1317b3695c 100644
--- a/tests/PHPStan/Analyser/nsrt/for-loop-i-type.php
+++ b/tests/PHPStan/Analyser/nsrt/for-loop-i-type.php
@@ -94,4 +94,12 @@ public static function groupCapacities(array $startTimes): array
 
 		return $capacities;
 	}
+
+	public function lastConditionResult(): void
+	{
+		for ($i = 0, $j = 5; $i < 10, $j > 0; $i++, $j--) {
+			assertType('int<0, max>', $i); // int<0,4> would be more precise, see https://github.com/phpstan/phpstan/issues/11872
+			assertType('int<1, 5>', $j);
+		}
+	}
 }