bool -> (int, float) and (int, float) -> bool implicit cast removed

[ThakeeNathees]

Fix: #40249
Fix #26248

[dalexeev]

Note that the following code will no longer work:

func _item_selected(idx: int) -> void:
    get_tree().debug_collisions_hint = idx & 0b01
    get_tree().debug_navigation_hint = idx & 0b10

Explicit conversion will be required:

func _item_selected(idx: int) -> void:
    get_tree().debug_collisions_hint = bool(idx & 0b01)
    get_tree().debug_navigation_hint = bool(idx & 0b10)

[ThakeeNathees]

if we support implicit casting between boolean and numerical types than it also needs to support arithmetic operations too. the below line should be valid (it's not now).

dir.x = Input.is_key_pressed(KEY_A) - Input.is_key_pressed(KEY_D);

[aaronfranke]

@ThakeeNathees Is this still desired? If so, this needs to be rebased on the latest master branch.

[ThakeeNathees]

@aaronfranke done

[MewPurPur]

Sooo what's the status on this?

[Calinou]

Sooo what's the status on this?

This is a compatibility-breaking change, so I think it should be implemented as a GDScript warning instead. (I think this may already exists as "unsafe cast" or "unsafe assignment".)

We may want a specific warning for those particular bool-to-int/float cases (and vice versa) though. This one could be enabled by default in projects created after this PR is merged (using the approach described in godotengine/godot-proposals#4834).