Filter out empty-typed binders in selector cases.

[matthijs/master-project/cλash.git] / cλash / CLasH / VHDL / Generate.hs

diff --git a/cλash/CLasH/VHDL/Generate.hs b/cλash/CLasH/VHDL/Generate.hs
index 31c9c8d7f11f192eb5f12b68030579cf50caf567..5386e7e61b698a0681830ffc9b4b14c2c9c1e67f 100644 (file)
--- a/cλash/CLasH/VHDL/Generate.hs
+++ b/cλash/CLasH/VHDL/Generate.hs
@@ -166,7 +166,8 @@ mkConcSm (bndr, expr@(CoreSyn.Case (CoreSyn.Var scrut) b ty [alt]))
                 | otherwise =
   case alt of
     (CoreSyn.DataAlt dc, bndrs, (CoreSyn.Var sel_bndr)) -> do
-      case List.elemIndex sel_bndr bndrs of
+      bndrs' <- Monad.filterM hasNonEmptyType bndrs
+      case List.elemIndex sel_bndr bndrs' of
         Just i -> do
           labels <- MonadState.lift tsType $ getFieldLabels (Id.idType scrut)
           let label = labels!!i
@@ -204,11 +205,19 @@ genExprArgs wrap dst func args = do
 
 -- | Turn the all lefts into VHDL Expressions.
 argsToVHDLExprs :: [Either CoreSyn.CoreExpr AST.Expr] -> TranslatorSession [AST.Expr]
-argsToVHDLExprs = mapM argToVHDLExpr
-
-argToVHDLExpr :: Either CoreSyn.CoreExpr AST.Expr -> TranslatorSession AST.Expr
-argToVHDLExpr (Left expr) = MonadState.lift tsType $ varToVHDLExpr (exprToVar expr)
-argToVHDLExpr (Right expr) = return expr
+argsToVHDLExprs = catMaybesM . (mapM argToVHDLExpr)
+
+argToVHDLExpr :: Either CoreSyn.CoreExpr AST.Expr -> TranslatorSession (Maybe AST.Expr)
+argToVHDLExpr (Left expr) = MonadState.lift tsType $ do
+  let errmsg = "Generate.argToVHDLExpr: Using non-representable type? Should not happen!"
+  ty_maybe <- vhdl_ty errmsg expr
+  case ty_maybe of
+    Just _ -> do
+      vhdl_expr <- varToVHDLExpr $ exprToVar expr
+      return $ Just vhdl_expr
+    Nothing -> return $ Nothing
+
+argToVHDLExpr (Right expr) = return $ Just expr
 
 -- A function to wrap a builder-like function that generates no component
 -- instantiations