default case

src/Juvix/Compiler/Internal/Translation/FromConcrete.hs

@@ -569,19 +569,35 @@ deriveEq instanceName funParams (eqName, args) = do
       let loc = getLoc eqName
       band <- getBuiltin loc BuiltinBoolAnd
       btrue <- getBuiltin loc BuiltinBoolTrue
+      bfalse <- getBuiltin loc BuiltinBoolFalse
       bisEqual <- getBuiltin loc BuiltinIsEqual
       case nonEmpty (d ^. Internal.inductiveInfoConstructors) of
         Nothing -> return (Internal.toExpression btrue)
         Just cs -> do
           cl' <- mapM (lambdaClause band btrue bisEqual) cs
+          defaultCl' <-
+            if
+                | notNull (NonEmpty.tail cs) -> Just <$> defaultLambdaClause bfalse
+                | otherwise -> return Nothing
           return
             ( Internal.ExpressionLambda
                 Internal.Lambda
                   { _lambdaType = Nothing,
-                    _lambdaClauses = cl'
+                    _lambdaClauses = snocNonEmptyMaybe cl' defaultCl'
                   }
             )
       where
+        defaultLambdaClause :: Internal.Name -> Sem r Internal.LambdaClause
+        defaultLambdaClause btrue = do
+          let loc = getLoc eqName
+          p1 <- Internal.genWildcard loc Internal.Explicit
+          p2 <- Internal.genWildcard loc Internal.Explicit
+          return
+            Internal.LambdaClause
+              { _lambdaPatterns = p1 :| [p2],
+                _lambdaBody = Internal.toExpression btrue
+              }
+
         lambdaClause ::
           Internal.FunctionName ->
           Internal.FunctionName ->
@@ -620,7 +636,7 @@ deriveEq instanceName funParams (eqName, args) = do
               def <- getDefinedConstructor c
               let cargs :: [Internal.FunctionParameter] = Internal.constructorArgs (def ^. Internal.constructorInfoType)
               unless (all ((== Explicit) . (^. Internal.paramImplicit)) cargs) (error "TODO all args must be explicit")
-              return (length args)
+              return (length cargs)
 
 goFunctionDef ::
   forall r.