Do not let conditional expressions unset variables with proven Yes certainty in filterBySpecifiedTypes

src/Analyser/MutatingScope.php

@@ -3263,6 +3263,12 @@ public function filterBySpecifiedTypes(SpecifiedTypes $specifiedTypes): self
 		foreach ($conditions as $conditionalExprString => $expressions) {
 			$certainty = TrinaryLogic::lazyExtremeIdentity($expressions, static fn (ConditionalExpressionHolder $holder) => $holder->getTypeHolder()->getCertainty());
 			if ($certainty->no()) {
+				if (
+					array_key_exists($conditionalExprString, $scope->expressionTypes)
+					&& $scope->expressionTypes[$conditionalExprString]->getCertainty()->yes()
+				) {
+					continue;
+				}
 				unset($scope->expressionTypes[$conditionalExprString]);
 			} else {
 				if (array_key_exists($conditionalExprString, $scope->expressionTypes)) {

tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php

@@ -1531,4 +1531,13 @@ public function testBug6688(): void
 		]);
 	}
 
+	public function testBug14353(): void
+	{
+		$this->cliArgumentsVariablesRegistered = true;
+		$this->polluteScopeWithLoopInitialAssignments = true;
+		$this->checkMaybeUndefinedVariables = true;
+		$this->polluteScopeWithAlwaysIterableForeach = true;
+		$this->analyse([__DIR__ . '/data/bug-14353.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Variables/data/bug-14353.php

@@ -0,0 +1,68 @@
+<?php
+
+namespace Bug14353;
+
+/** @return array<int> */
+function get(): array
+{
+	return [1];
+}
+
+class Test
+{
+	public function test(): void
+	{
+		$reports = [];
+
+		foreach (get() as $report) {
+			$reports[$report] = $report;
+		}
+
+		if (isset($this->data)) {
+			foreach ($reports as $report_id => $report) {
+				$report_ids[$report_id] = 1;
+			}
+		} else {
+			foreach ($reports as $report_id => $report) {
+				$report_ids[$report_id] = 1;
+			}
+		}
+
+		if (isset($report_ids)) {
+			var_dump($report_ids);
+
+			foreach ($reports as $report) {}
+
+			var_dump($report_ids);
+		}
+	}
+
+	public function testWithIfBranch(): void
+	{
+		$reports = [];
+
+		foreach (get() as $report) {
+			$reports[$report] = $report;
+		}
+
+		if (isset($this->data)) {
+			foreach ($reports as $report_id => $report) {
+				$report_ids[$report_id] = 1;
+			}
+		} else {
+			foreach ($reports as $report_id => $report) {
+				$report_ids[$report_id] = 1;
+			}
+		}
+
+		if (isset($report_ids)) {
+			var_dump($report_ids);
+
+			if ($reports === []) {
+				echo 'empty';
+			}
+
+			var_dump($report_ids);
+		}
+	}
+}