swap = fun '(x, y) => (y, x)
     : A * B -> B * A
fun '(x, y) => (y, x)
     : A * B -> B * A
forall '(x, y), swap (x, y) = (y, x)
     : Prop
proj_informative = fun '(exist _ x _) => x : A
     : {x : A | P x} -> A
foo = fun '(Bar n b tt p) => if b then n + p else n - p
     : Foo -> nat
baz = 
fun '(Bar n1 _ tt p1) => fun '(Bar _ _ tt _) => n1 + p1
     : Foo -> Foo -> nat
λ '(x, y), (y, x)
     : A * B → B * A
∀ '(x, y), swap (x, y) = (y, x)
     : Prop
swap = 
fun (A B : Type) (pat : A * B) => let '(x, y) := pat in (y, x)
     : forall A B : Type, A * B -> B * A

Arguments A, B are implicit and maximally inserted
Argument scopes are [type_scope type_scope _]
forall (A B : Type) (pat : A * B), let '(x, y) := pat in swap (x, y) = (y, x)
     : Prop
exists pat : A * A, let '(x, y) := pat in swap (x, y) = (y, x)
     : Prop
both_z = 
fun pat : nat * nat =>
let '(n, p) as pat0 := pat return (F pat0) in (Z n, Z p) : F (n, p)
     : forall pat : nat * nat, F pat