From Coq Require Import Int63 PArray.

Open Scope array_scope.

Definition t : array nat := [| 1; 3; 2 | 4 |].
Definition t' : array nat := t.[1 <- 5].

Definition foo1 := (eq_refl : t'.[1] = 5).
Definition foo2 := (eq_refl 5 <: t'.[1] = 5).
Definition foo3 := (eq_refl 5 <<: t'.[1] = 5).
Definition x1 := Eval compute in t'.[1].
Definition foo4 := (eq_refl : x1 = 5).
Definition x2 := Eval cbn in t'.[1].
Definition foo5 := (eq_refl : x2 = 5).

Definition foo6 := (eq_refl : t.[1] = 3).
Definition foo7 := (eq_refl 3 <: t.[1] = 3).
Definition foo8 := (eq_refl 3 <<: t.[1] = 3).
Definition x3 := Eval compute in t.[1].
Definition foo9 := (eq_refl : x3 = 3).
Definition x4 := Eval cbn in t.[1].
Definition foo10 := (eq_refl : x4 = 3).