Spelling in comments

compiler/hsSyn/HsPat.hs

@@ -137,7 +137,7 @@ data Pat id
 
   | ConPatOut {
         pat_con     :: Located ConLike,
-        pat_arg_tys :: [Type],          -- The univeral arg types, 1-1 with the universal
+        pat_arg_tys :: [Type],          -- The universal arg types, 1-1 with the universal
                                         -- tyvars of the constructor/pattern synonym
                                         --   Use (conLikeResTy pat_con pat_arg_tys) to get
                                         --   the type of the pattern

compiler/typecheck/TcHsType.hs

@@ -1242,7 +1242,7 @@ This is bad because throwing away the kind checked type throws away
 its splices.  But too bad for now.  [July 03]
 
 Historical note:
-    We no longer specify that these type variables must be univerally
+    We no longer specify that these type variables must be universally
     quantified (lots of email on the subject).  If you want to put that
     back in, you need to
         a) Do a checkSigTyVars after thing_inside

compiler/typecheck/TcSMonad.hs

@@ -763,7 +763,7 @@ The idea is that
   have (a -fs-> a) in S, which contradicts (WF2).
 
 * The extended substitution satisfies (WF1) and (WF2)
-  - (K1) plus (L1) guarantee that the extended substiution satisfies (WF1).
+  - (K1) plus (L1) guarantee that the extended substitution satisfies (WF1).
   - (T3) guarantees (WF2).
 
 * (K2) is about inertness.  Intuitively, any infinite chain T^0(f,t),