scopedunifhint.lean:28:7-28:14: error: application type mismatch
  mul ?m x
argument
  x
has type
  Nat : Type
but is expected to have type
  ?m.α : Type ?u
scopedunifhint.lean:29:7-29:24: error: application type mismatch
  mul ?m (x, x)
argument
  (x, x)
has type
  Nat × Nat : Type
but is expected to have type
  ?m.α : Type ?u
scopedunifhint.lean:33:7-33:10: error: application type mismatch
  ?m*x
argument
  x
has type
  Nat : Type
but is expected to have type
  ?m.α : Type ?u
x*x : Nat.Magma.α
x*x : Nat.Magma.α
scopedunifhint.lean:39:7-39:24: error: application type mismatch
  ?m*(x, x)
argument
  (x, x)
has type
  Nat × Nat : Type
but is expected to have type
  ?m.α : Type ?u
(x, x)*(x, x) : (Prod.Magma Nat.Magma Nat.Magma).α
scopedunifhint.lean:56:7-56:22: error: application type mismatch
  ?m*(x, x)
argument
  (x, x)
has type
  Nat × Nat : Type
but is expected to have type
  ?m.α : Type ?u