Fix #13303

Author: ondrejmirtes

src/Analyser/MutatingScope.php

@@ -3799,7 +3799,7 @@ public function filterBySpecifiedTypes(SpecifiedTypes $specifiedTypes): self
 			$scope->getNamespace(),
 			$scope->expressionTypes,
 			$scope->nativeExpressionTypes,
-			array_merge($specifiedTypes->getNewConditionalExpressionHolders(), $scope->conditionalExpressions),
+			$this->mergeConditionalExpressions($specifiedTypes->getNewConditionalExpressionHolders(), $scope->conditionalExpressions),
 			$scope->inClosureBindScopeClasses,
 			$scope->anonymousFunctionReflection,
 			$scope->inFirstLevelStatement,
@@ -3988,6 +3988,25 @@ private function intersectConditionalExpressions(array $otherConditionalExpressi
 		return $newConditionalExpressions;
 	}
 
+	/**
+	 * @param array<string, ConditionalExpressionHolder[]> $newConditionalExpressions
+	 * @param array<string, ConditionalExpressionHolder[]> $existingConditionalExpressions
+	 * @return array<string, ConditionalExpressionHolder[]>
+	 */
+	private function mergeConditionalExpressions(array $newConditionalExpressions, array $existingConditionalExpressions): array
+	{
+		$result = $existingConditionalExpressions;
+		foreach ($newConditionalExpressions as $exprString => $holders) {
+			if (!array_key_exists($exprString, $result)) {
+				$result[$exprString] = $holders;
+			} else {
+				$result[$exprString] = array_merge($result[$exprString], $holders);
+			}
+		}
+
+		return $result;
+	}
+
 	/**
 	 * @param array<string, ConditionalExpressionHolder[]> $conditionalExpressions
 	 * @param array<string, ExpressionTypeHolder> $ourExpressionTypes

src/Analyser/NodeScopeResolver.php

@@ -4363,6 +4363,13 @@ function (MutatingScope $scope) use ($stmt, $expr, $nodeCallback, $context, $sto
 				$matchScope = $matchScope->filterByFalseyValue($filteringExpr);
 			}
 
+			if (!$hasDefaultCond && !$hasAlwaysTrueCond && $condType->isBoolean()->yes() && $condType->isConstantScalarValue()->yes()) {
+				if ($this->isScopeConditionallyImpossible($matchScope)) {
+					$hasAlwaysTrueCond = true;
+					$matchScope = $matchScope->addTypeToExpression($expr->cond, new NeverType());
+				}
+			}
+
 			if (!$hasDefaultCond && !$hasAlwaysTrueCond) {
 				$remainingType = $matchScope->getType($expr->cond);
 				if (!$remainingType instanceof NeverType) {
@@ -7579,6 +7586,57 @@ private function getFilteringExprForMatchArm(Expr\Match_ $expr, array $condition
 		);
 	}
 
+	/**
+	 * Checks if a scope's conditional expressions form a contradiction,
+	 * meaning no combination of variable values is possible.
+	 * Used for match(true) exhaustiveness detection.
+	 */
+	private function isScopeConditionallyImpossible(MutatingScope $scope): bool
+	{
+		$boolVars = [];
+		foreach ($scope->getDefinedVariables() as $varName) {
+			$varType = $scope->getVariableType($varName);
+			if ($varType->isBoolean()->yes() && !$varType->isConstantScalarValue()->yes()) {
+				$boolVars[] = $varName;
+			}
+		}
+
+		if ($boolVars === []) {
+			return false;
+		}
+
+		// Check if any boolean variable's both truth values lead to contradictions
+		foreach ($boolVars as $varName) {
+			$varExpr = new Variable($varName);
+			$truthyScope = $scope->filterByTruthyValue($varExpr);
+			$falseyScope = $scope->filterByFalseyValue($varExpr);
+
+			$truthyContradiction = $this->scopeHasNeverVariable($truthyScope, $boolVars);
+			$falseyContradiction = $this->scopeHasNeverVariable($falseyScope, $boolVars);
+
+			if ($truthyContradiction && $falseyContradiction) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	 * @param string[] $varNames
+	 */
+	private function scopeHasNeverVariable(MutatingScope $scope, array $varNames): bool
+	{
+		foreach ($varNames as $varName) {
+			$type = $scope->getVariableType($varName);
+			if ($type instanceof NeverType) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
 	private function inferForLoopExpressions(For_ $stmt, Expr $lastCondExpr, MutatingScope $bodyScope): MutatingScope
 	{
 		// infer $items[$i] type from for ($i = 0; $i < count($items); $i++) {...}

src/Analyser/SpecifiedTypes.php

@@ -188,6 +188,16 @@ public function unionWith(SpecifiedTypes $other): self
 			$result = $result->setAlwaysOverwriteTypes();
 		}
 
+		$conditionalExpressionHolders = $this->newConditionalExpressionHolders;
+		foreach ($other->newConditionalExpressionHolders as $exprString => $holders) {
+			if (!array_key_exists($exprString, $conditionalExpressionHolders)) {
+				$conditionalExpressionHolders[$exprString] = $holders;
+			} else {
+				$conditionalExpressionHolders[$exprString] = array_merge($conditionalExpressionHolders[$exprString], $holders);
+			}
+		}
+		$result->newConditionalExpressionHolders = $conditionalExpressionHolders;
+
 		return $result->setRootExpr($rootExpr);
 	}
 

src/Analyser/TypeSpecifier.php

@@ -645,14 +645,24 @@ public function specifyTypesInCondition(
 			$rightTypes = $this->specifyTypesInCondition($rightScope, $expr->right, $context)->setRootExpr($expr);
 			$types = $context->true() ? $leftTypes->unionWith($rightTypes) : $leftTypes->normalize($scope)->intersectWith($rightTypes->normalize($rightScope));
 			if ($context->false()) {
+				$leftTypesForHolders = $leftTypes;
+				$rightTypesForHolders = $rightTypes;
+				if ($context->truthy()) {
+					if ($leftTypesForHolders->getSureTypes() === [] && $leftTypesForHolders->getSureNotTypes() === []) {
+						$leftTypesForHolders = $this->specifyTypesInCondition($scope, $expr->left, TypeSpecifierContext::createFalsey())->setRootExpr($expr);
+					}
+					if ($rightTypesForHolders->getSureTypes() === [] && $rightTypesForHolders->getSureNotTypes() === []) {
+						$rightTypesForHolders = $this->specifyTypesInCondition($rightScope, $expr->right, TypeSpecifierContext::createFalsey())->setRootExpr($expr);
+					}
+				}
 				return (new SpecifiedTypes(
 					$types->getSureTypes(),
 					$types->getSureNotTypes(),
 				))->setNewConditionalExpressionHolders(array_merge(
-					$this->processBooleanNotSureConditionalTypes($scope, $leftTypes, $rightTypes),
-					$this->processBooleanNotSureConditionalTypes($scope, $rightTypes, $leftTypes),
-					$this->processBooleanSureConditionalTypes($scope, $leftTypes, $rightTypes),
-					$this->processBooleanSureConditionalTypes($scope, $rightTypes, $leftTypes),
+					$this->processBooleanNotSureConditionalTypes($scope, $leftTypesForHolders, $rightTypesForHolders),
+					$this->processBooleanNotSureConditionalTypes($scope, $rightTypesForHolders, $leftTypesForHolders),
+					$this->processBooleanSureConditionalTypes($scope, $leftTypesForHolders, $rightTypesForHolders),
+					$this->processBooleanSureConditionalTypes($scope, $rightTypesForHolders, $leftTypesForHolders),
 				))->setRootExpr($expr);
 			}
 

tests/PHPStan/Rules/Classes/ImpossibleInstanceOfRuleTest.php

@@ -494,6 +494,11 @@ public function testBug3632(): void
 
 		$tipText = 'Because the type is coming from a PHPDoc, you can turn off this check by setting <fg=cyan>treatPhpDocTypesAsCertain: false</> in your <fg=cyan>%configurationFile%</>.';
 		$this->analyse([__DIR__ . '/data/bug-3632.php'], [
+			[
+				'Instanceof between null and Bug3632\NiceClass will always evaluate to false.',
+				32,
+				$tipText,
+			],
 			[
 				'Instanceof between Bug3632\NiceClass and Bug3632\NiceClass will always evaluate to true.',
 				36,

tests/PHPStan/Rules/Comparison/MatchExpressionRuleTest.php

@@ -405,4 +405,15 @@ public function testBug13048(): void
 		$this->analyse([__DIR__ . '/data/bug-13048.php'], []);
 	}
 
+	#[RequiresPhp('>= 8.0')]
+	public function testBug13303(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-13303.php'], [
+			[
+				'Match expression does not handle remaining value: true',
+				34,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Comparison/data/bug-13303.php

@@ -0,0 +1,39 @@
+<?php // lint >= 8.0
+
+namespace Bug13303;
+
+function a(bool $b, bool $c): int {
+	return match(true) {
+		$b && $c => 1,
+		!$b && !$c => 2,
+		!$b && $c => 3,
+		$b && !$c => 4,
+	};
+}
+
+function b(bool $b, bool $c): int {
+	return match(true) {
+		$b && $c,
+		!$b && !$c => 1,
+		!$b && $c,
+		$b && !$c => 2,
+	};
+}
+
+function c(bool $b, bool $c): int {
+	return match(true) {
+		$b === true && $c === true => 1,
+		$b === false && $c === false => 2,
+		$b === false && $c === true => 3,
+		$b === true && $c === false => 4,
+	};
+}
+
+function d(bool $b, bool $c): int {
+	// Not exhaustive - should still report error
+	return match(true) {
+		$b && $c => 1,
+		!$b && !$c => 2,
+		!$b && $c => 3,
+	};
+}