diff --git a/src/Lib/TopContext.newt b/src/Lib/TopContext.newt
index babc5f7..055136e 100644
--- a/src/Lib/TopContext.newt
+++ b/src/Lib/TopContext.newt
@@ -43,8 +43,7 @@ instance Show TopContext where
 emptyTop : ∀ io. {{Monad io}} {{HasIO io}} -> io TopContext
 emptyTop = do
   let mcctx = MC emptyMap Nil 0 CheckAll
-  errs <- newIORef $ the (List Error) Nil
-  pure $ MkTop emptyMap Nil emptyMap Nil emptyMap mcctx 0 errs emptyMap
+  pure $ MkTop emptyMap Nil emptyMap Nil emptyMap mcctx 0 Nil emptyMap
 
 
 setFlag : QName → FC → EFlag → M Unit
@@ -91,4 +90,4 @@ addHint qn = do
 addError : Error -> M Unit
 addError err = do
   top <- getTop
-  modifyIORef top.errors (_::_ err)
+  modifyTop [ errors $= _::_ err ]
diff --git a/src/Lib/Types.newt b/src/Lib/Types.newt
index 9e76a18..faa1061 100644
--- a/src/Lib/Types.newt
+++ b/src/Lib/Types.newt
@@ -433,7 +433,7 @@ record TopContext where
 
   -- Global values
   verbose : Int -- command line flag
-  errors : IORef (List Error)
+  errors : List Error
   ops : Operators
 
 -- we'll use this for typechecking, but need to keep a TopContext around too.
diff --git a/src/Main.newt b/src/Main.newt
index e54fdc8..cd32e52 100644
--- a/src/Main.newt
+++ b/src/Main.newt
@@ -165,19 +165,15 @@ processModule importFC base stk qn@(QN ns nm) = do
   top <- getTop
 
   let mod = MkModCtx csum top.defs top.metaCtx top.ops
-  errors <- liftIO {M} $ readIORef top.errors
-  if stk /= Nil && length' errors == 0
+  if stk /= Nil && length' top.errors == 0
     then dumpModule qn src mod
     else pure MkUnit
 
   let modules = updateMap modns mod top.modules
   modifyTop [modules := modules]
 
-  (Nil) <- liftIO {M} $ readIORef top.errors
-    | errors => do
-        -- we're now showing errors when they occur, so they're next to debug messages
-        -- traverse (putStrLn ∘ showError src) errors
-        exitFailure "Compile failed"
+  let (Nil) = top.errors
+    | errors => exitFailure "Compile failed"
   logMetas $ reverse $ listValues top.metaCtx.metas
   pure src
   where
@@ -199,7 +195,7 @@ showErrors : String -> String -> M Unit
 showErrors fn src = do
   top <- getTop
   -- TODO {M} needed to sort out scrutinee
-  (Nil) <- liftIO {M} $ readIORef top.errors
+  let (Nil) = top.errors
     | errors => do
         traverse (putStrLn ∘ showError src) errors
         exitFailure "Compile failed"