diff --git a/src/DiffSummary.hs b/src/DiffSummary.hs
index 3187f6734..dee7d6086 100644
--- a/src/DiffSummary.hs
+++ b/src/DiffSummary.hs
@@ -155,7 +155,7 @@ determiner (LeafInfo "else block" _ _) = "an"
 determiner (LeafInfo "ensure block" _ _) = "an"
 determiner (LeafInfo "when block" _ _) = "a"
 determiner (LeafInfo "anonymous function" _ _) = "an"
-determiner (BranchInfo bs _ _) = determiner (last bs)
+determiner (BranchInfo bs _ _) = maybe "" determiner (snd <$> unsnoc bs)
 determiner _ = "the"
 
 toLeafInfos :: DiffInfo -> [JSONSummary Doc SourceSpan]
diff --git a/src/Prologue.hs b/src/Prologue.hs
index a59ad3cac..61a7687e5 100644
--- a/src/Prologue.hs
+++ b/src/Prologue.hs
@@ -5,11 +5,10 @@ module Prologue
 , (***)
 , hylo, cata, para, ana
 , module Data.Hashable
-, last
 ) where
 
 import Protolude as X
-import Data.List (lookup, last)
+import Data.List (lookup)
 
 import Control.Comonad.Trans.Cofree as X
 import Control.Monad.Trans.Free as X
diff --git a/src/Source.hs b/src/Source.hs
index 2fdd4fc4c..30d6aafe9 100644
--- a/src/Source.hs
+++ b/src/Source.hs
@@ -103,7 +103,7 @@ sourceSpanToRange source SourceSpan{..} = Range start end
 rangeToSourceSpan :: Source Char -> Range -> SourceSpan
 rangeToSourceSpan source range@Range{} = SourceSpan startPos endPos
   where startPos = maybe (SourcePos 1 1) (toStartPos 1) (head lineRanges)
-        endPos = toEndPos (length lineRanges) (last lineRanges)
+        endPos = toEndPos (length lineRanges) (fromMaybe (rangeAt 0) (snd <$> unsnoc lineRanges))
         lineRanges = actualLineRanges range source
         toStartPos line range = SourcePos line (start range)
         toEndPos line range = SourcePos line (end range)