PhpdocToParamTypeFixer - fix for breaking PHP syntax for type having reserved name

[kubawerlos]

Twin PR to #4963

I wonder if it would be useful to have some class e.g. SyntaxChecker with (static?) method isValid, which will handle cache internally and all needed will be to call it like this:

if (!SyntaxChecker::isValid(sprintf('<?php function f(%s $x) {}', $returnType))) {
    continue;
}

Currently, this will have 2 uses (here and PhpdocToReturnTypeFixer, maybe also AbstractPsrAutoloadingFixer, not mandatory), but I imagine quite soon we will have PhpdocToPropertyTypeFixer.

[julienfalque]

[...] but I imagine quite soon we will have PhpdocToPropertyTypeFixer.

Indeed, #4592 introduces a parent abstract class where we could move this logic but a dedicated class sounds better :)

[kubawerlos]

@julienfalque the idea with SyntaxValidator failed as to validate the code in PHP 5.6 Tokens class fails and only working solution, which is using eval is... you know evil ;)

Let's try with placing the check in AbstractPhpdocToTypeDeclarationFixer.

[SpacePossum]

I liked the validator more (composition over inheritance), can you explain the issue on 5.6 a bit more?

[kubawerlos]

Tokens::fromCode runs token_get_all under the hood, with TOKEN_PARSE flag if it exists, but it does not in PHP 5.6. Without the flag everything is valid -> https://3v4l.org/CfW8M

And that call was actually the validation done in SyntaxValidator class.

Also as composition over inheritance is usually what I want to do in this case I'm not so sure - adding class SyntaxValidator would be like stating: "Look, here is the class to use in fixers" and I don't want to do that - I cannot see any other case when we would like to do this.

[SpacePossum]

Thank you @kubawerlos.