Fix phpstan/phpstan#11619: Parameter #2 $callback of function uasort expects callable(Foo, Foo): int, 'strnatcasecmp' given.

[phpstan-bot]

Summary

PHPStan incorrectly reported an error when passing a string-comparison function like strnatcasecmp to uasort() for arrays of Stringable objects. For example, uasort($options, 'strnatcasecmp') where $options is Foo[] and Foo implements Stringable would produce: "Parameter #2 $callback of function uasort expects callable(Foo, Foo): int, 'strnatcasecmp' given."

This is a false positive because PHP's internal functions like strnatcasecmp perform implicit type coercion from Stringable to string.

Changes

• src/Type/CallableType.php: Propagated the $strictTypes parameter from accepts() through isSuperTypeOfInternal() to CallableTypeHelper::isParametersAcceptorSuperTypeOf()
• src/Type/CallableTypeHelper.php: Added optional $strictTypes parameter (default true) and used it in the callable parameter acceptance check instead of the hardcoded true
• tests/PHPStan/Rules/Functions/data/bug-11619.php: New regression test with Stringable class and uasort/usort with strnatcasecmp
• tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php: Added testBug11619 test method

Root cause

CallableType::accepts() received a $strictTypes parameter but ignored it, always passing treatMixedAsAny=true to its internal method without forwarding $strictTypes. The CallableTypeHelper::isParametersAcceptorSuperTypeOf() hardcoded strictTypes=true when calling $theirParameter->getType()->accepts(), which caused StringType::accepts() to reject Stringable objects without checking for __toString().

The fix propagates the scope's $strictTypes value through the chain. In non-strict mode (no declare(strict_types=1)), StringType::accepts() now checks for __toString() and accepts Stringable objects. In strict mode, the existing behavior is preserved, which correctly handles cases like bug-12317 where a user-defined closure with explicit string parameter types should still be flagged.

Test

Added tests/PHPStan/Rules/Functions/data/bug-11619.php with a Stringable class Foo and calls to uasort($options, 'strnatcasecmp') and usort($options, 'strnatcasecmp'). The test expects no errors.

Fixes phpstan/phpstan#11619