Feature request

Description

Currently, type assertions like @phpstan-assert-if-true work perfectly for direct function calls. However, when a function is converted to a First-class callable (...), it becomes a Closure and loses its original assertion metadata. The same limitation applies to string callables.

It would be a great feature if PHPStan could propagate or retain these assertion definitions within the resulting Closure type so that type narrowing works even when the function is invoked dynamically.

Playground

https://phpstan.org/r/3b0c30b7-5eba-4fb2-89df-02ee7a8c8d2d

Expected Result

PHPStan should ideally be able to track the @phpstan-assert-if-true metadata on the created Closure (or callable), narrowing the type of $v to int<1, max> successfully without emitting errors.

Actual Result

The assertion context is not preserved, resulting in the following errors:

  23     Expected type int<1, max>, actual: mixed
         🪪  phpstan.type (non-ignorable)
  27     Expected type int<1, max>, actual: mixed
         🪪  phpstan.type (non-ignorable)

Did PHPStan help you today? Did it make you happy in any way?

No response