What would make more sense to me would be to drop the equals sign in the cases where we’re doing a kind of type-hint.
E.g. if we omitted the equals sign:
def foo(bar %Plug.Conn{}), do: "matched when input is a plug"
def foo(bar %Ecto.Changeset{}), do: "matched when input is a changeset"
def foo(bar %{status: "valid"}), do: "matched when input is a map with a status key with a value of valid"
# ... etc...
In all cases, bar gets the full input, it just happened to be filtered according to the type – conceptually something like a guard clause.
That would be more similar to how other languages do the type-hinting (e.g. Go and PHP, although PHP puts the type to the left of the variable).
There still is pattern matching going on there, but it’s not happening directly in the function, it’s happening immediately before when the kernel is choosing which function signature matches. This only comes up in cases where you need to get the full value of a variable, but you need to some pre-emptive filtering.
