Make β-λ more generic (Argument can now be any type T instead of `Setn L)

SubjectReduction/Specification.agda

@@ -383,8 +383,8 @@ data _⊢_⦂_ : ∀ {n} → Context n → Term n → Term n → Set where
       --------------
     → Γ ⊢ ` x ⦂ t
 
-  ⊢-λ : ∀ {n} {Γ : Context n} {e : Term (suc n)} {t₁ l : Term n} {t₂ : Term (suc n)}
-    → Γ ⊢ t₁ ⦂ `Setn l
+  ⊢-λ : ∀ {n} {Γ : Context n} {e : Term (suc n)} {t₁ T₁ : Term n} {t₂ : Term (suc n)}
+    → Γ ⊢ t₁ ⦂ T₁
     → Γ , t₁ ⊢ e ⦂ t₂
       -----------------------
     → Γ ⊢ `λ e ⦂ ∀[x⦂ t₁ ] t₂
@@ -447,6 +447,7 @@ data _⊢_⦂_ : ∀ {n} → Context n → Term n → Term n → Set where
       ------------------------------
     → Γ ⊢ `subst t e₁ e₂ ⦂ t [ u₂ ]
 
+
 -- Extension
   ⊢-Setn : ∀ {n} {Γ : Context n} {l}
     → Γ ⊢ `Setn l ⦂ (`Setn (`lsuc l))
@@ -471,4 +472,3 @@ data _⊢_⦂_ : ∀ {n} → Context n → Term n → Term n → Set where
 
 cong₃ : ∀ {A B C D : Set} (f : A → B → C → D) {x y u v a b} → x ≡ y → u ≡ v → a ≡ b → f x u a ≡ f y v b
 cong₃ f refl refl refl = refl
-