Type Narrowing caused by Type\instance_of

[bendavies]

Hi,

Given a variable that the type is already known:

$foo = Type\instance_of(BarInterface::class)->assert($foo);
$foo = Type\instance_of(FooInterface::class)->assert($foo);

Then type of $foo will become FooInterface, but I would expect BarInterface&FooInterface

What do you think?

Thanks

[herndlm]

assert makes it throw in case the type does not match I presume?

Most likely the extension cannot handle the assert yet, since phpstan itself handles that just fine. See e.g. https://phpstan.org/r/13ea6cd2-061b-47ac-925e-ee1f50c86c0e. Without assert support it would kind of translate to the second block and therefore loose type information in the scope.

[bendavies]

Using a class and an Interface was a bad example on my part.

Using 2 interfaces is the real use case.

I've edited the OP