Skip ClosureToArrowFunctionRector when closure has @var docblock

[QDenka]

Summary

Fixes rectorphp/rector#9637

Arrow functions do not support inline @var annotations for type narrowing. When a closure contains a @var docblock (e.g. /** @var Builder<Team> $query */), converting it to an arrow function breaks PHPStan type narrowing since there is no way to apply @var type annotations within arrow functions.

Problem

Previously, the rule only skipped conversion when the @var type was more specific than the native type (via type comparison). However, this comparison could fail with generics (e.g. Builder<Team> vs Builder), causing unintended conversions.

Example from the issue:

// Before (correct - PHPStan recognizes the type narrowing)
function (Builder $query) {
    /** @var Builder<Team> $query */
    return $query->inFullNameOrder();
}

// After (broken - @var has no effect in arrow functions)
/** @var Builder<Team> $query */
fn(Builder $query) => $query->inFullNameOrder()

Solution

Skip ClosureToArrowFunctionRector whenever a @var tag is present on the return statement, regardless of type comparison. This is the safe approach because:

1. If the user placed a @var docblock, they did so intentionally
2. Arrow functions cannot support @var annotations for type narrowing
3. Type comparison with generics is unreliable

Changes

• Simplified shouldSkipMoreSpecificTypeWithVarDoc() to skip on any @var presence
• Removed unused NodeTypeResolver and MixedType dependencies
• Added test fixture for generic type @var docblock scenario
• Updated with_equal_var_doc_type fixture to be a skip test (equal types should also be preserved)

[TomasVotruba]

Thanks for detailed analysis. I agree this reduction to arrow function would remove important metadata and context, that is clearly intended to keep.