fix reviewers' comments

src/Horus/CFGBuild.hs

@@ -20,7 +20,7 @@ module Horus.CFGBuild
 where
 
 import Control.Arrow (Arrow (second))
-import Control.Monad (unless, when)
+import Control.Monad (when)
 import Control.Monad.Except (MonadError (..))
 import Control.Monad.Free.Church (F, liftF)
 import Data.Coerce (coerce)
@@ -160,8 +160,9 @@ getSalientVertex :: Label -> CFGBuildL Vertex
 getSalientVertex l = do
   verts <- filter (not . isOptimising) <$> getVerts l
   -- This can be at most one, so len <> 1 implies there are no vertices
-  unless (length verts == 1) . throw $ "No vertex with label: " <> tShow l
-  pure $ head verts
+  case verts of
+    [vert] -> pure vert
+    _ -> throw $ "No vertex with label: " <> tShow l
 
 throw :: Text -> CFGBuildL a
 throw t = liftF' (Throw t)

src/Horus/CFGBuild/Runner.hs

@@ -56,9 +56,9 @@ verticesLabelledBy cfg l = [v | v <- cfg_vertices cfg, v_label v == l]
 interpret :: CFGBuildL a -> Impl a
 interpret = iterM exec . runCFGBuildL
  where
-  exec (AddVertex l isOptimizing cont) = do
+  exec (AddVertex l optimises cont) = do
     freshVal <- cfgVertexCounter <%= succ
-    let newVertex = Vertex (Text.pack (show freshVal)) l isOptimizing
+    let newVertex = Vertex (Text.pack (show freshVal)) l optimises
     vs <- gets cfg_vertices
     -- Currently, the design is such that it is convenient to be able to distinguish
     -- 'the unique vertex the entire codebase relies on' from vertices that exist

src/Horus/CairoSemantics.hs

@@ -26,7 +26,7 @@ import Data.Traversable (for)
 import Lens.Micro ((^.), _1)
 
 import Horus.CallStack as CS (CallEntry, CallStack)
-import Horus.Expr (Cast (..), Expr (ExistsFelt, (:+)), Ty (..), (.&&), (./=), (.<), (.<=), (.==), (.=>), (.||))
+import Horus.Expr (Cast (..), Expr ((:+)), Ty (..), (.&&), (./=), (.<), (.<=), (.==), (.=>), (.||))
 import Horus.Expr qualified as Expr
 import Horus.Expr qualified as TSMT
 import Horus.Expr.Util (gatherLogicalVariables, suffixLogicalVariables)
@@ -227,12 +227,8 @@ preparePost ap fp expr isOptim = do
     then do
       memVars <- getMemVars
       post <- storageRemoval expr
-      ($ memVars) <$> exMemoryRemoval (substitute "fp" fp (substitute "ap" ap (sansExists post)))
-    else prepare' ap fp $ sansExists expr
- where
-  sansExists e = case e of
-    ExistsFelt _ innerExpr -> innerExpr
-    _ -> e
+      ($ memVars) <$> exMemoryRemoval (substitute "fp" fp (substitute "ap" ap post))
+    else prepare' ap fp expr
 
 encodeApTracking :: Text -> ApTracking -> Expr TFelt
 encodeApTracking traceDescr ApTracking{..} =