ES: bugfix in TrivialCaseElimination

Author: Anabra

grin/src/Transformations/ExtendedSyntax/Optimising/TrivialCaseElimination.hs

@@ -9,6 +9,6 @@ trivialCaseElimination :: Exp -> Exp
 trivialCaseElimination = ana builder where
   builder :: Exp -> ExpF Exp
   builder = \case
-    ECase scrut [Alt DefaultPat _altName body] -> SBlockF body
-    ECase scrut [Alt cpat       _altName body] -> SBlockF $ EBind (SReturn (Var scrut)) (cPatToAsPat scrut cpat) body
+    ECase scrut [Alt DefaultPat altName body] -> SBlockF $ EBind (SReturn (Var scrut)) (VarPat altName)           body
+    ECase scrut [Alt cpat       altName body] -> SBlockF $ EBind (SReturn (Var scrut)) (cPatToAsPat altName cpat) body
     exp -> project exp