diff --git a/src/Language/PureScript/AST/Declarations.hs b/src/Language/PureScript/AST/Declarations.hs
index 9c820071dc..2725f5da67 100644
--- a/src/Language/PureScript/AST/Declarations.hs
+++ b/src/Language/PureScript/AST/Declarations.hs
@@ -124,7 +124,7 @@ data SimpleErrorMessage
   | DuplicateValueDeclaration Ident
   | ArgListLengthsDiffer Ident
   | OverlappingArgNames (Maybe Ident)
-  | MissingClassMember Ident
+  | MissingClassMember (NEL.NonEmpty (Ident, Type))
   | ExtraneousClassMember Ident (Qualified (ProperName 'ClassName))
   | ExpectedType Type Kind
   -- | constructor name, expected argument count, actual argument count
diff --git a/src/Language/PureScript/Errors.hs b/src/Language/PureScript/Errors.hs
index 135f98aa2f..2eb422d1d5 100644
--- a/src/Language/PureScript/Errors.hs
+++ b/src/Language/PureScript/Errors.hs
@@ -753,8 +753,12 @@ prettyPrintSingleError (PPEOptions codeColor full level showDocs relPath) e = fl
       line $ "Argument list lengths differ in declaration " <> markCode (showIdent ident)
     renderSimpleErrorMessage (OverlappingArgNames ident) =
       line $ "Overlapping names in function/binder" <> foldMap ((" in declaration " <>) . showIdent) ident
-    renderSimpleErrorMessage (MissingClassMember ident) =
-      line $ "Type class member " <> markCode (showIdent ident) <> " has not been implemented."
+    renderSimpleErrorMessage (MissingClassMember identsAndTypes) =
+      paras $ [ line "The following type class members have not been implemented:"
+              , Box.vcat Box.left
+                [ markCodeBox $ Box.text (T.unpack (showIdent ident)) Box.<> " :: " Box.<> typeAsBox ty
+                | (ident, ty) <- NEL.toList identsAndTypes ]
+              ]
     renderSimpleErrorMessage (ExtraneousClassMember ident className) =
       line $ "" <> markCode (showIdent ident) <> " is not a member of type class " <> markCode (showQualified runProperName className)
     renderSimpleErrorMessage (ExpectedType ty kind) =
diff --git a/src/Language/PureScript/Sugar/TypeClasses.hs b/src/Language/PureScript/Sugar/TypeClasses.hs
index a6c80750b7..0645bcde7d 100644
--- a/src/Language/PureScript/Sugar/TypeClasses.hs
+++ b/src/Language/PureScript/Sugar/TypeClasses.hs
@@ -14,9 +14,11 @@ import           Control.Arrow (first, second)
 import           Control.Monad.Error.Class (MonadError(..))
 import           Control.Monad.State
 import           Control.Monad.Supply.Class
-import           Data.List ((\\), find, sortBy)
+import           Data.List (find, sortBy)
 import qualified Data.Map as M
 import           Data.Maybe (catMaybes, mapMaybe, isJust, fromMaybe)
+import qualified Data.List.NonEmpty as NEL
+import qualified Data.Set as S
 import           Data.Text (Text)
 import qualified Language.PureScript.Constants as C
 import           Language.PureScript.Crash
@@ -285,12 +287,14 @@ typeInstanceDictionaryDeclaration sa@(ss, _) name mn deps className tys decls =
     maybe (throwError . errorMessage' ss . UnknownName $ fmap TyClassName className) return $
       M.lookup (qualify mn className) m
 
-  case map fst typeClassMembers \\ mapMaybe declIdent decls of
-    member : _ -> throwError . errorMessage' ss $ MissingClassMember member
-    [] -> do
-      -- Replace the type arguments with the appropriate types in the member types
-      let memberTypes = map (second (replaceAllTypeVars (zip (map fst typeClassArguments) tys))) typeClassMembers
+  -- Replace the type arguments with the appropriate types in the member types
+  let memberTypes = map (second (replaceAllTypeVars (zip (map fst typeClassArguments) tys))) typeClassMembers
+
+  let declaredMembers = S.fromList $ mapMaybe declIdent decls
 
+  case filter (\(ident, _) -> not $ S.member ident declaredMembers) memberTypes of
+    hd : tl -> throwError . errorMessage' ss $ MissingClassMember (hd NEL.:| tl)
+    [] -> do
       -- Create values for the type instance members
       members <- zip (map typeClassMemberName decls) <$> traverse (memberToValue memberTypes) decls
 
diff --git a/tests/purs/failing/MissingClassMember.purs b/tests/purs/failing/MissingClassMember.purs
index 488fccfc99..42a06a927f 100644
--- a/tests/purs/failing/MissingClassMember.purs
+++ b/tests/purs/failing/MissingClassMember.purs
@@ -1,11 +1,10 @@
 -- @shouldFailWith MissingClassMember
 module Main where
 
-import Prelude
-
 class A a where
   a :: a -> String
   b :: a -> Number
+  c :: forall f. a -> f a
 
 instance aString :: A String where
   a s = s