Fix param-out generics via stubs

[staabm]

triggered by discussion in ee737e6#commitcomment-138984141

[staabm]

@rvanvelzen may I ask you for your opinion on these conditional types involved, as I think you are the expert :)?

---

I am wondering why we resolve @param differently compared to @param-out

phpstan-src/src/Reflection/ResolvedFunctionVariant.php

Lines 75 to 83 in 39dc97b

	$paramType = TypeUtils::resolveLateResolvableTypes(
	TemplateTypeHelper::resolveTemplateTypes(
	$this->resolveConditionalTypesForParameter($param->getType()),
	$this->resolvedTemplateTypeMap,
	$this->callSiteVarianceMap,
	TemplateTypeVariance::createContravariant(),
	),
	false,
	);

vs.

phpstan-src/src/Reflection/ResolvedFunctionVariant.php

Lines 85 to 93 in 39dc97b

	$paramOutType = $param->getOutType();
	if ($paramOutType !== null) {
	$paramOutType = TemplateTypeHelper::resolveTemplateTypes(
	$paramOutType,
	$this->resolvedTemplateTypeMap,
	$this->callSiteVarianceMap,
	TemplateTypeVariance::createCovariant(),
	);
	}

harmonizing this does not yet make a difference though, as the conditional types involved are not ConditionalTypeForParameter for param-out. so I am wondering whether phpdoc-parser needs adjustments to produce ConditionalTypeForParameter instead of ConditionalType for param-out...?

[rvanvelzen]

The reason the added tests fail is because anonymous functions don't support phpdocs, so the parameter type is never set correctly.

Why sort etc. didn't work before is because coming from the signature map they're defined as PassedByReference::readsArgument() instead of PassedByReference::createsNewVariable(), so the out-type is never used.

As for the conditional parameters: it probably hasn't been a use-case for now. I didn't implement param-out types 😉