Merge pull request #5188 from unisonweb/lsp/unused-binding-detection

Unused binding detection cleanup

lib/unison-prelude/src/Unison/Debug.hs

@@ -147,7 +147,7 @@ debugPatternCoverageConstraintSolver = PatternCoverageConstraintSolver `Set.memb
 debug :: (Show a) => DebugFlag -> String -> a -> a
 debug flag msg a =
   if shouldDebug flag
-    then (pTrace (msg <> ":\n" <> into @String (pShow a)) a)
+    then (trace (msg <> ":\n" <> into @String (pShow a)) a)
     else a
 
 -- | Use for selective debug logging in monadic contexts.

unison-cli/src/Unison/LSP/FileAnalysis/UnusedBindings.hs

@@ -15,26 +15,37 @@ import Unison.Parser.Ann (Ann)
 import Unison.Prelude
 import Unison.Symbol (Symbol (..))
 import Unison.Term (Term)
+import Unison.Util.Monoid qualified as Monoid
 import Unison.Util.Range qualified as Range
 import Unison.Var qualified as Var
 
 analyseTerm :: Lsp.Uri -> Ann -> Term Symbol Ann -> [Diagnostic]
 analyseTerm fileUri topLevelTermAnn tm =
   let (unusedVars, _) = ABT.cata alg tm
-   in Map.toList unusedVars & mapMaybe \(v, _ann) -> do
-        name <- getRelevantVarName v
-        -- Unfortunately we don't capture the annotation of the actual binding when parsing :'(, for now the least
-        -- annoying thing to do is just highlight the top of the binding.
-        urange <- Cv.annToURange topLevelTermAnn <&> (\(Range.Range start@(Pos.Pos line _col) _end) -> Range.Range start (Pos.Pos line 9999))
-        let lspRange = Cv.uToLspRange urange
-        pure $ Diagnostic.mkDiagnostic fileUri lspRange Diagnostic.DiagnosticSeverity_Warning ("Unused binding " <> tShow name <> " inside this term.\nUse the binding, or prefix it with an _ to dismiss this warning.") []
+      -- Unfortunately we don't capture the annotation of the actual binding when parsing :'(, for now the least
+      -- annoying thing to do is just highlight the top of the binding.
+      mayRange =
+        Cv.annToURange topLevelTermAnn
+          <&> (\(Range.Range start@(Pos.Pos line _col) _end) -> Range.Range start (Pos.Pos line 9999))
+          <&> Cv.uToLspRange
+      vars =
+        Map.toList unusedVars & mapMaybe \(v, _ann) -> do
+          getRelevantVarName v
+   in case mayRange of
+        Nothing -> []
+        Just lspRange ->
+          let bindings = Text.intercalate ", " (tShow <$> vars)
+           in Monoid.whenM (not $ null vars) [Diagnostic.mkDiagnostic fileUri lspRange Diagnostic.DiagnosticSeverity_Warning ("Unused binding(s) " <> bindings <> " inside this term.\nUse the binding(s), or prefix them with an _ to dismiss this warning.") []]
   where
     getRelevantVarName :: Symbol -> Maybe Text
     getRelevantVarName = \case
+      -- Sometimes 'do' gets a binding of '()', which we don't care about
+      Symbol _ (Var.User "()") -> Nothing
+      Symbol _ (Var.User "") -> Nothing
       -- We only care about user bindings which don't start with an underscore
       Symbol _ (Var.User n) -> do
         guard (not (Text.isPrefixOf "_" n))
-        pure n
+        Just n
       _ -> Nothing
     alg :: (Foldable f, Ord v) => Ann -> ABT f v (Map v Ann, Set v) -> (Map v Ann, Set v)
     alg ann abt = case abt of