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Intersect stored FuncCall expression types with dynamically computed types in MutatingScope::resolveType() #5454

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Intersect stored FuncCall expression types with dynamically computed types in MutatingScope::resolveType() #5454

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98dad9b
Intersect stored `FuncCall` expression types with dynamically compute…
github-actions[bot] Apr 13, 2026
fba232d
Move FuncCall type update from resolveType() to filterBySpecifiedTypes()
phpstan-bot Apr 14, 2026
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20 changes: 19 additions & 1 deletion src/Analyser/MutatingScope.php
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Original file line number Diff line number Diff line change
Expand Up @@ -973,7 +973,25 @@ private function resolveType(string $exprString, Expr $node): Type
&& !$node instanceof Expr\ArrowFunction
&& $this->hasExpressionType($node)->yes()
) {
return $this->expressionTypes[$exprString]->getType();
$storedType = $this->expressionTypes[$exprString]->getType();

if ($node instanceof FuncCall) {
// Stored expression types for function calls can become stale
// when arguments are narrowed after scope merging.
// Intersect with the dynamically computed type to stay correct.
$this->resolvedTypes[$exprString] = $storedType;
foreach ($this->container->getServicesByTag(ExprHandler::EXTENSION_TAG) as $exprHandler) {
if (!$exprHandler->supports($node)) {
continue;
}
$dynamicType = $exprHandler->resolveType($this, $node);
unset($this->resolvedTypes[$exprString]);
return TypeCombinator::intersect($storedType, $dynamicType);
}
unset($this->resolvedTypes[$exprString]);
}

return $storedType;
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@staabm staabm Apr 14, 2026

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instead of re-calculating types at type-resolving time, couldn't we make sure expressionTypes are properly updated when evaluating the AST?

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@phpstan-bot phpstan-bot Apr 14, 2026

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Done. Here's a summary of the changes made to address staabm's review:

Review feedback: Instead of re-calculating types at type-resolving time, update expressionTypes during AST evaluation.

What changed:

  1. Reverted resolveType() back to its original behavior - no more special FuncCall handling at type resolution time.

  2. Added FuncCall type updating in filterBySpecifiedTypes() - when type narrowing is applied from conditions (e.g., $arr !== [] narrows $arr), the method now detects stored FuncCall expression types whose arguments were actually narrowed and updates them by intersecting the stored type with the freshly computed dynamic type.

Key design decisions:

  • Intersection, not invalidation: Simply removing stale FuncCall types would lose precision from conditions on the function result (e.g., count($arr) === 3 gives 3, not int<1, max>). Intersecting preserves narrowing from both sources.
  • Type change guard: Only updates FuncCall entries when the argument's type actually changed, avoiding unnecessary recomputation when narrowing is redundant.
  • Skip specified/conditional entries: FuncCall expressions that were directly specified or updated by conditional expressions are left alone.

Test results: All 11,855 tests pass, PHPStan self-analysis passes with no errors.

}

/** @var ExprHandler<Expr> $exprHandler */
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52 changes: 52 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 +1,52 @@
<?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 forgetCountDifferentNarrowing(array $arr): void
{
if (count($arr) > 2) {
}
if ($arr !== []) {
assertType('int<1, max>', count($arr));
}
}

/** @param array<mixed> $arr */
public function sizeofAfterSizeof(array $arr): void
{
if (sizeof($arr) > 2) {
}
if ($arr !== []) {
assertType('int<1, max>', sizeof($arr));
}
}

public function strlenAfterStrlen(string $str): void
{
if (strlen($str) > 5) {
}
if ($str !== '') {
assertType('int<1, max>', strlen($str));
}
}
}
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