diff --git a/courses/tspl/2019/Assignment4.lagda.md b/courses/tspl/2019/Assignment4.lagda.md
index 89c3dd10..dd4179df 100644
--- a/courses/tspl/2019/Assignment4.lagda.md
+++ b/courses/tspl/2019/Assignment4.lagda.md
@@ -982,15 +982,15 @@ Remember to indent all code by two spaces.
 ```
   ext∋ : ∀ {Γ B x y}
     → x ≢ y
-    → ¬ ( ∃[ A ] Γ ∋ x ⦂ A )
-      -----------------------------
-    → ¬ ( ∃[ A ] Γ , y ⦂ B ∋ x ⦂ A )
+    → ¬ (∃[ A ]( Γ ∋ x ⦂ A ))
+      ------------------------------
+    → ¬ (∃[ A ]( Γ , y ⦂ B ∋ x ⦂ A ))
   ext∋ x≢y _  ⟨ A , Z ⟩       =  x≢y refl
   ext∋ _   ¬∃ ⟨ A , S _ ⊢x ⟩  =  ¬∃ ⟨ A , ⊢x ⟩
 
   lookup : ∀ (Γ : Context) (x : Id)
-      -----------------------
-    → Dec (∃[ A ](Γ ∋ x ⦂ A))
+           ------------------------
+         → Dec (∃[ A ](Γ ∋ x ⦂ A))
   lookup ∅ x                        =  no  (λ ())
   lookup (Γ , y ⦂ B) x with x ≟ y
   ... | yes refl                    =  yes ⟨ B , Z ⟩
@@ -1006,7 +1006,7 @@ Remember to indent all code by two spaces.
     → Γ ⊢ L ↑ A ⇒ B
     → ¬ Γ ⊢ M ↓ A
       ----------------------------
-    → ¬ ( ∃[ B′ ] Γ ⊢ L · M ↑ B′ )
+    → ¬ (∃[ B′ ]( Γ ⊢ L · M ↑ B′ ))
   ¬arg ⊢L ¬⊢M ⟨ B′ , ⊢L′ · ⊢M′ ⟩ rewrite dom≡ (uniq-↑ ⊢L ⊢L′) = ¬⊢M ⊢M′
 
   ¬switch : ∀ {Γ M A B}
@@ -1022,12 +1022,12 @@ Remember to indent all code by two spaces.
 
 ```
   synthesize : ∀ (Γ : Context) (M : Term⁺)
-      -----------------------
-    → Dec (∃[ A ](Γ ⊢ M ↑ A))
+               -----------------------
+             → Dec (∃[ A ]( Γ ⊢ M ↑ A ))
 
   inherit : ∀ (Γ : Context) (M : Term⁻) (A : Type)
-      ---------------
-    → Dec (Γ ⊢ M ↓ A)
+            ---------------
+          → Dec (Γ ⊢ M ↓ A)
 
   synthesize Γ (` x) with lookup Γ x
   ... | no  ¬∃              =  no  (λ{ ⟨ A , ⊢` ∋x ⟩ → ¬∃ ⟨ A , ∋x ⟩ })
diff --git a/stack.yaml b/stack.yaml
index 0a7399d6..45c8f85a 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,7 +1,7 @@
 resolver: lts-17.2
 
-# Use GHC 8.10.3
-compiler: ghc-8.10.3
+# Use GHC 8.10.5
+compiler: ghc-8.10.5
 compiler-check: match-exact
 
 # Allow never versions of packages