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Intersect cached count()/strlen() expression types with current argument type constraints #5702

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Intersect cached count()/strlen() expression types with current argument type constraints #5702

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21aa9b0
Intersect cached `count()`/`strlen()` expression types with current a…
staabm May 18, 2026
6b424f6
Refine dependent expression types at storage time instead of retrieva…
phpstan-bot May 19, 2026
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22 changes: 21 additions & 1 deletion src/Analyser/MutatingScope.php
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Original file line number Diff line number Diff line change
Expand Up @@ -972,7 +972,27 @@ private function resolveType(string $exprString, Expr $node): Type
&& !$node instanceof Expr\ArrowFunction
&& $this->hasExpressionType($node)->yes()
) {
return $this->expressionTypes[$exprString]->getType();
$type = $this->expressionTypes[$exprString]->getType();

if (
$node instanceof FuncCall
&& $node->name instanceof Name
&& !$node->isFirstClassCallable()
&& count($node->getArgs()) >= 1
) {
$funcName = $node->name->toLowerString();
if (in_array($funcName, ['count', 'sizeof'], true)) {
$argType = $this->getType($node->getArgs()[0]->value);
$type = TypeCombinator::intersect($type, $argType->getArraySize());
} elseif (
in_array($funcName, ['strlen', 'mb_strlen'], true)
&& $this->getType($node->getArgs()[0]->value)->isNonEmptyString()->yes()
) {
$type = TypeCombinator::intersect($type, IntegerRangeType::fromInterval(1, null));
}
}
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@staabm staabm May 19, 2026

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why do we need to patch the types after the fact, instead of remembering the proper types in the first place?

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@phpstan-bot phpstan-bot May 19, 2026

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Pushed. Here's a summary of what changed:

The reviewer's concern: Why patch cached types on retrieval instead of storing the correct types from the start?

The fix: Moved the refinement logic from resolveType() (retrieval time) to specifyExpressionType() (storage time). When a variable's type is narrowed via specifyExpressionType, the new refineDependentFuncCallTypes method scans expressionTypes for count()/sizeof()/strlen()/mb_strlen() FuncCall entries whose first argument matches the narrowed variable, and intersects their cached types with the constraint derived from the new variable type. This ensures cached expression types are always correct when retrieved, rather than being patched after the fact.

The resolveType() method is back to simply returning the cached type directly.

  • make phpstan — no errors
  • make tests — all 12,105 tests pass
  • Verified test fails without any fix, passes with the storage-time fix


return $type;
}

/** @var ExprHandler<Expr> $exprHandler */
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84 changes: 84 additions & 0 deletions tests/PHPStan/Analyser/nsrt/bug-13750.php
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Original file line number Diff line number Diff line change
@@ -0,0 +1,84 @@
<?php

namespace Bug13750;

use function PHPStan\Testing\assertType;

class HelloWorld
{
/** @param array<mixed> $arr */
public function forgetCount(array $arr): void
{
if (count($arr) > 2) {
assertType('non-empty-array<mixed>', $arr);
assertType('int<3, max>', count($arr));
}
assertType('array<mixed>', $arr);
assertType('int<0, max>', count($arr));
if (count($arr, COUNT_RECURSIVE) > 2) {
assertType('non-empty-array<mixed>', $arr);
assertType('int<1, max>', count($arr));
}
}

/** @param array<mixed> $arr */
public function sizeofAfterCount(array $arr): void
{
if (sizeof($arr) > 2) {
assertType('int<3, max>', sizeof($arr));
}
assertType('int<0, max>', sizeof($arr));
if (sizeof($arr, COUNT_RECURSIVE) > 2) {
assertType('non-empty-array<mixed>', $arr);
assertType('int<1, max>', sizeof($arr));
}
}

/** @param array<mixed> $arr */
public function countAfterNonEmptyNarrowing(array $arr): void
{
if (count($arr) > 2) {
assertType('int<3, max>', count($arr));
}
assertType('int<0, max>', count($arr));
if ($arr !== []) {
assertType('non-empty-array<mixed>', $arr);
assertType('int<1, max>', count($arr));
}
}

/** @param array<mixed> $arr */
public function nestedCountPreservation(array $arr): void
{
if (count($arr) > 2) {
assertType('int<3, max>', count($arr));
if (count($arr, COUNT_RECURSIVE) > 10) {
assertType('int<3, max>', count($arr));
}
}
}

public function strlenAfterNonEmptyNarrowing(string $str): void
{
if (strlen($str) > 5) {
assertType('int<6, max>', strlen($str));
}
assertType('int<0, max>', strlen($str));
if ($str !== '') {
assertType('non-empty-string', $str);
assertType('int<1, max>', strlen($str));
}
}

public function mbStrlenAfterNonEmptyNarrowing(string $str): void
{
if (mb_strlen($str) > 5) {
assertType('int<6, max>', mb_strlen($str));
}
assertType('int<0, max>', mb_strlen($str));
if ($str !== '') {
assertType('non-empty-string', $str);
assertType('int<1, max>', mb_strlen($str));
}
}
}
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