Issue:
Explosion.Hit:Connect uses (Instance, number) instead of (BasePart, number) (Take note of how BasePart.Touched uses (BasePart).) Explosion.Hit will only fire for BaseParts so using Instance in the type checking is a bit confusing and also hides BasePart specific functions from the type checker.
See: Explosion | Roblox Creator Documentation
Expected Behavior:
Change the Instance type checking to BasePart. This will allow the type checker to know that BasePart functions exist on the Instance being passed so developers don’t get warnings for this.
Repro:
local Expl:Explosion = Instance.new'Explosion'
Expl.Hit:Connect(function(Part: BasePart, Distance:number): ()
print('Hit part: ' .. Part:GetFullName())
end)
Pictures:
