updated Stack snapshot; handled pattern matching failure issues introduced in GHC 8.6

src/Convert/Traverse.hs

@@ -130,11 +130,14 @@ traverseModuleItemsM mapper (Part extern kw lifetime name ports items) = do
                 isGenModuleItem (GenModuleItem _) = True
                 isGenModuleItem _ = False
         breakGenerate other = [other]
-
 traverseModuleItemsM mapper (PackageItem packageItem) = do
     let item = MIPackageItem packageItem
-    Part False Module Nothing "DNE" [] [item'] <-
+    converted <-
         traverseModuleItemsM mapper (Part False Module Nothing "DNE" [] [item])
+    let item' = case converted of
+            Part False Module Nothing "DNE" [] [newItem] -> newItem
+            _ -> error $ "redirected PackageItem traverse failed: "
+                    ++ show converted
     return $ case item' of
         MIPackageItem packageItem' -> PackageItem packageItem'
         other -> error $ "encountered bad package module item: " ++ show other
@@ -605,8 +608,12 @@ traverseLHSsM' strat mapper item =
             lhs' <- mapper lhs
             return $ NInputGate kw x lhs' exprs
         traverseModuleItemLHSsM (AssertionItem (mx, a)) = do
-            Assertion a' <- traverseNestedStmtsM (traverseStmtLHSsM mapper) (Assertion a)
-            return $ AssertionItem (mx, a')
+            converted <-
+                traverseNestedStmtsM (traverseStmtLHSsM mapper) (Assertion a)
+            return $ case converted of
+                Assertion a' -> AssertionItem (mx, a')
+                _ -> error $ "redirected AssertionItem traverse failed: "
+                        ++ show converted
         traverseModuleItemLHSsM other = return other
 
 traverseLHSs' :: TFStrategy -> Mapper LHS -> Mapper ModuleItem
@@ -795,8 +802,12 @@ collectAsgnsM = collectAsgnsM' IncludeTFs
 
 traverseNestedModuleItemsM :: Monad m => MapperM m ModuleItem -> MapperM m ModuleItem
 traverseNestedModuleItemsM mapper item = do
-    Part False Module Nothing "DNE" [] items' <-
+    converted <-
         traverseModuleItemsM mapper (Part False Module Nothing "DNE" [] [item])
+    let items' = case converted of
+            Part False Module Nothing "DNE" [] newItems -> newItems
+            _ -> error $ "redirected NestedModuleItems traverse failed: "
+                    ++ show converted
     return $ case items' of
         [item'] -> item'
         _ -> Generate $ map GenModuleItem items'

src/Language/SystemVerilog/Parser/Lex.x

@@ -463,9 +463,13 @@ takeThrough goal = do
 -- pop one character from the input stream
 takeChar :: Alex Char
 takeChar = do
-    (pos, _, _, ch : str) <- alexGetInput
+    (pos, _, _, str) <- alexGetInput
+    (ch, chs) <-
+        if null str
+            then lexicalError "unexpected end of input"
+            else return (head str, tail str)
     let newPos = alexMove pos ch
-    alexSetInput (newPos, ch, [], str)
+    alexSetInput (newPos, ch, [], chs)
     return ch
 
 -- drop spaces in the input until a non-space is reached or EOF
@@ -497,7 +501,8 @@ dropWhitespace = do
     where
         dropChar :: Alex ()
         dropChar = do
-            (pos, _, _, ch : rest) <- alexGetInput
+            (pos, _, _, chs) <- alexGetInput
+            let ch : rest = chs
             alexSetInput (alexMove pos ch, ch, [], rest)
 
 -- removes and returns a quoted string such as <foo.bar> or "foo.bar"
@@ -558,8 +563,11 @@ takeMacroDefinition = do
 takeMacroArguments :: Alex [String]
 takeMacroArguments = do
     dropSpaces
-    '(' <- takeChar
-    argLoop
+    leadCh <- takeChar
+    if leadCh == '('
+        then argLoop
+        else lexicalError $ "expected begining of macro arguments, but found "
+                ++ show leadCh
     where
         argLoop :: Alex [String]
         argLoop = do

stack.yaml

@@ -1,4 +1,4 @@
-resolver: lts-12.5
+resolver: lts-13.17
 
 packages:
 - .