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Fix phpstan/phpstan#12790: false positive “Match expression does not handle remaining value: int<...>” for match (count(...)) { ...} #5228

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Merged
ondrejmirtes merged 2 commits into from
Mar 16, 2026
+38 −4
Merged

Fix phpstan/phpstan#12790: false positive “Match expression does not handle remaining value: int<...>” for match (count(...)) { ...} #5228

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a8996a7
Fix match expression not recognizing exhaustive count() arms
ondrejmirtes Mar 16, 2026
9d8387b
Use $leftExpr instead of $unwrappedLeftExpr for func type narrowing i…
phpstan-bot Mar 16, 2026
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12 changes: 8 additions & 4 deletions src/Analyser/TypeSpecifier.php
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Original file line number Diff line number Diff line change
Expand Up @@ -2568,7 +2568,7 @@ private function resolveNormalizedIdentical(Expr\BinaryOp\Identical $expr, Scope
$argType = $scope->getType($unwrappedLeftExpr->getArgs()[0]->value);
$isZero = (new ConstantIntegerType(0))->isSuperTypeOf($rightType);
if ($isZero->yes()) {
$funcTypes = $this->create($unwrappedLeftExpr, $rightType, $context, $scope)->setRootExpr($expr);
$funcTypes = $this->create($leftExpr, $rightType, $context, $scope)->setRootExpr($expr);

if ($context->truthy() && !$argType->isArray()->yes()) {
$newArgType = new UnionType([
Expand All @@ -2586,11 +2586,15 @@ private function resolveNormalizedIdentical(Expr\BinaryOp\Identical $expr, Scope

$specifiedTypes = $this->specifyTypesForCountFuncCall($unwrappedLeftExpr, $argType, $rightType, $context, $scope, $expr);
if ($specifiedTypes !== null) {
if ($leftExpr !== $unwrappedLeftExpr) {
$funcTypes = $this->create($leftExpr, $rightType, $context, $scope)->setRootExpr($expr);
return $specifiedTypes->unionWith($funcTypes);
}
return $specifiedTypes;
}

if ($context->truthy() && $argType->isArray()->yes()) {
$funcTypes = $this->create($unwrappedLeftExpr, $rightType, $context, $scope)->setRootExpr($expr);
$funcTypes = $this->create($leftExpr, $rightType, $context, $scope)->setRootExpr($expr);
if (IntegerRangeType::fromInterval(1, null)->isSuperTypeOf($rightType)->yes()) {
return $funcTypes->unionWith(
$this->create($unwrappedLeftExpr->getArgs()[0]->value, new NonEmptyArrayType(), $context, $scope)->setRootExpr($expr),
Expand All @@ -2616,7 +2620,7 @@ private function resolveNormalizedIdentical(Expr\BinaryOp\Identical $expr, Scope

$isZero = (new ConstantIntegerType(0))->isSuperTypeOf($rightType);
if ($isZero->yes()) {
$funcTypes = $this->create($unwrappedLeftExpr, $rightType, $context, $scope)->setRootExpr($expr);
$funcTypes = $this->create($leftExpr, $rightType, $context, $scope)->setRootExpr($expr);
return $funcTypes->unionWith(
$this->create($unwrappedLeftExpr->getArgs()[0]->value, new ConstantStringType(''), $context, $scope)->setRootExpr($expr),
);
Expand All @@ -2625,7 +2629,7 @@ private function resolveNormalizedIdentical(Expr\BinaryOp\Identical $expr, Scope
if ($context->truthy() && IntegerRangeType::fromInterval(1, null)->isSuperTypeOf($rightType)->yes()) {
$argType = $scope->getType($unwrappedLeftExpr->getArgs()[0]->value);
if ($argType->isString()->yes()) {
$funcTypes = $this->create($unwrappedLeftExpr, $rightType, $context, $scope)->setRootExpr($expr);
$funcTypes = $this->create($leftExpr, $rightType, $context, $scope)->setRootExpr($expr);

$accessory = new AccessoryNonEmptyStringType();
if (IntegerRangeType::fromInterval(2, null)->isSuperTypeOf($rightType)->yes()) {
Expand Down
6 changes: 6 additions & 0 deletions tests/PHPStan/Rules/Comparison/MatchExpressionRuleTest.php
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Expand Up @@ -453,6 +453,12 @@ public function testBug13029(): void
$this->analyse([__DIR__ . '/data/bug-13029.php'], []);
}

#[RequiresPhp('>= 8.0')]
public function testBug12790(): void
{
$this->analyse([__DIR__ . '/data/bug-12790.php'], []);
}

#[RequiresPhp('>= 8.0')]
public function testBug11310(): void
{
Expand Down
24 changes: 24 additions & 0 deletions tests/PHPStan/Rules/Comparison/data/bug-12790.php
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Original file line number Diff line number Diff line change
@@ -0,0 +1,24 @@
<?php // lint >= 8.0

declare(strict_types = 1);

namespace Bug12790;

$r = [];
$r[] = 'a';
if (rand(0, 1)) {
$r[] = 'b';
}

echo match (count($r)) {
1 => 'one',
2 => 'two',
};

/** @param 'a'|'ab' $s */
function matchStrlen(string $s): string {
return match (strlen($s)) {
1 => 'one',
2 => 'two',
};
}
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