RemoveRedundantTypeCast should not remove required downcast

[protocol7]

Adds a failing test case for where RemoveRedundantTypeCast should not remove a downcast that is necessary for chained calls to get matching types.

[timtebeek]

Thanks for the runnable example!

[github-actions[bot]]

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[timtebeek]

Summary

I successfully fixed the dontRemoveNecessaryDowncast test in RemoveRedundantTypeCastTest. The issue was that the recipe was incorrectly removing a type cast in a generic method call chain:

Optional.of((Bar) getBarImpl()).orElse(getBar())

The cast (Bar) is necessary here because:

1. Without the cast, Optional.of(getBarImpl()) returns Optional<BarImpl>
2. With the cast, Optional.of((Bar) getBarImpl()) returns Optional<Bar>
3. The orElse(getBar()) method requires Optional<Bar> since getBar() returns Bar

The fix adds a special case check in the RemoveRedundantTypeCast recipe that preserves type casts when:

1. The cast is inside a method invocation
2. The cast is widening a type (e.g., from BarImpl to Bar)
3. The method returns a parameterized (generic) type

This ensures that casts that affect generic type inference are preserved, preventing type compatibility issues in method chains.

[protocol7]

Nice work!