Try to provide literal int types when possible (fixes #6966)

[ricardoboss]

This PR fixes #6966.

I added a return type provider for the round function, which will now try to return a literal float, which can then be used for further analysis.
The second change involves modifying the CastAnalyzer to also return a literal int when possible. I also tried to simplify the code a bit.

[orklah]

Thanks!

You have to enable the return type provider in FunctionReturnTypeProvider first

[orklah]

I made an error in my explanation. round only returns floats:

https://3v4l.org/ETvDv

That shouldn't be an issue however, what you have to do to fix #6966 is check if you have a TLiteralInt or a TLiteralFloat in the num_arg. If it is, you should return a TLiteralFloat with the rounded value of what was in num_arg.

[ricardoboss]

I need to implement the CastAnalyzer too. So this is should really be a draft PR.

[ricardoboss]

I'm struggling to get the actual values with which the round method was called. As you can see, I'm trying to get them with $call_args[1]->value, which gives a PhpParser\Node\Expr. How do I get the actual value?

[orklah]

try a $statements_analyzer->node_data->getType(...) on that. It may be a complex expression but Psalm should already have inferred it

[weirdan]

E.g.

psalm/src/Psalm/Internal/Provider/ReturnTypeProvider/ArrayFillReturnTypeProvider.php

Lines 27 to 30 in 25614ec

	$first_arg_type = isset($call_args[0]) ? $statements_source->node_data->getType($call_args[0]->value) : null;
	$second_arg_type = isset($call_args[1]) ? $statements_source->node_data->getType($call_args[1]->value) : null;
	$third_arg_type = isset($call_args[2]) ? $statements_source->node_data->getType($call_args[2]->value) : null;

[orklah]

@ricardoboss is this ready for review?

[ricardoboss]

Yes! Sorry I didn't notify you...

[orklah]

No worries, we'll check that :)

[ricardoboss]

@orklah can you take a look again?

[orklah]

See comment above. Can you add some tests too?

[orklah]

@ricardoboss do you need some help to design the tests?

Could you also rebase to solve the conflicts?

[ricardoboss]

Will do a rebase! I haven't had time to write tests yet. Haven't forgot it either.

[orklah]

Sorry for not coming back to this earlier, I don't get notifications for commits so I didn't see this change. I'll take a look. Don't hesitate to ping me or leave a comment when you change things

[orklah]

Seems fine. Can you rebase and fix the Code Style error please?

[ricardoboss]

Can you write a test for this? I would like to see how you test this behavior.

I will do a rebase when I get time to do so

[orklah]

For the cast one, you can add a test in ValueTest.php in providerValidCodeParse with the code: $a = (int)'5'; and in the assertions you can check $a=== => '5'

For the round one, you can add a test in FunctionCallTest.php in providerValidCodeParse with the code $a = round(5.111, 2); and in the assertions you can check $a=== => 'float(5.11)'

[orklah]

Thanks!

[kkmuffme]

The missing cast analyzer things are added in this PR now #8366 and this PR is cherry-picked to 4.x