diff --git a/lib/src/catalan/DiffCat.gf b/lib/src/catalan/DiffCat.gf
index 4eae5f6b6..fb38421e0 100644
--- a/lib/src/catalan/DiffCat.gf
+++ b/lib/src/catalan/DiffCat.gf
@@ -50,9 +50,9 @@ oper
       _ => prepCase c ++ artDef g Sg (CPrep P_de)
       } ;
 
-    conjunctCase : NPForm -> NPForm = \c -> case c of {
-      Ton Nom | Aton Nom => Ton Nom ;
-      _ => Ton Acc 
+    conjunctCase : Case -> Case = \c -> case c of {
+      Nom => Nom ;
+      _ => Acc 
       } ;
 
     auxVerb : VType -> (VF => Str) = \_ -> haver_V.s ;
diff --git a/lib/src/french/DiffFre.gf b/lib/src/french/DiffFre.gf
index 2deee816b..ec915c8c3 100644
--- a/lib/src/french/DiffFre.gf
+++ b/lib/src/french/DiffFre.gf
@@ -47,10 +47,7 @@ instance DiffFre of DiffRomance = open CommonRomance, PhonoFre, Prelude in {
       _ => prepCase c ++ artDef g Sg (CPrep P_de)
       } ;
 
-    conjunctCase : NPForm -> NPForm = \c -> case c of {
-      Aton k => Ton k ;
-      _ => c
-      } ;
+    conjunctCase : Case -> Case = \c -> c ;
 
     auxVerb : VType -> (VF => Str) = \vtyp -> case vtyp of {
       VHabere => avoir_V.s ;
diff --git a/lib/src/italian/DiffIta.gf b/lib/src/italian/DiffIta.gf
index 2006ce126..1f41a24af 100644
--- a/lib/src/italian/DiffIta.gf
+++ b/lib/src/italian/DiffIta.gf
@@ -62,9 +62,9 @@ instance DiffIta of DiffRomance = open CommonRomance, PhonoIta, BeschIta, Prelud
       _ => prepCase c ++ artDef g Sg (CPrep P_di)
       } ;
 
-    conjunctCase : NPForm -> NPForm = \c -> case c of {
-      Ton Nom | Aton Nom => Ton Nom ;
-      _ => Ton Acc 
+    conjunctCase : Case -> Case = \c -> case c of {
+      Nom => Nom ;
+      _ => Acc 
       } ;
 
     auxVerb : VType -> (VF => Str) = \vtyp -> case vtyp of {
diff --git a/lib/src/romance/ConjunctionRomance.gf b/lib/src/romance/ConjunctionRomance.gf
index 86bfda615..59861ada2 100644
--- a/lib/src/romance/ConjunctionRomance.gf
+++ b/lib/src/romance/ConjunctionRomance.gf
@@ -32,11 +32,11 @@ incomplete concrete ConjunctionRomance of Conjunction =
     ConsAdv = consrSS comma ;
     BaseNP x y = {
       s1 = \\c => (x.s ! c).ton ; 
-      s2 = \\c => (y.s ! c).ton ; ----e (conjunctCase c) ; 
+      s2 = \\c => (y.s ! conjunctCase c).ton ; ----e (conjunctCase c) ; 
       a = conjAgr x.a y.a
       } ;
     ConsNP x xs = {
-      s1 = \\c => (x.s ! c).ton ++ comma ++ xs.s1 ! c ; ----e (conjunctCase c) ; 
+      s1 = \\c => (x.s ! c).ton ++ comma ++ xs.s1 ! conjunctCase c ; ----e (conjunctCase c) ; 
       s2 = \\c => xs.s2 ! c ; ----e (conjunctCase c) ; 
       a = conjAgr x.a xs.a
       } ;
diff --git a/lib/src/romance/DiffRomance.gf b/lib/src/romance/DiffRomance.gf
index 424acfc16..be53051d3 100644
--- a/lib/src/romance/DiffRomance.gf
+++ b/lib/src/romance/DiffRomance.gf
@@ -34,7 +34,7 @@ interface DiffRomance = open CommonRomance, Prelude in {
 -- Whether a preposition is repeated in conjunction
 -- (Fre "la somme de 3 et de 4", Ita "la somma di 3 e 4").
 
-  oper conjunctCase : NPForm -> NPForm ;
+  oper conjunctCase : Case -> Case ;
 
 -- How infinitives and clitics are placed relative to each other
 -- (Fre "la voir", Ita "vederla"). The $Bool$ is used for indicating
diff --git a/lib/src/spanish/DiffSpa.gf b/lib/src/spanish/DiffSpa.gf
index dc0a2f352..624bea852 100644
--- a/lib/src/spanish/DiffSpa.gf
+++ b/lib/src/spanish/DiffSpa.gf
@@ -47,9 +47,9 @@ instance DiffSpa of DiffRomance = open CommonRomance, PhonoSpa, BeschSpa, Prelud
       } ;
 -}
 
-    conjunctCase : NPForm -> NPForm = \c -> case c of {
-      Ton Nom | Aton Nom => Ton Nom ;
-      _ => Ton Acc 
+    conjunctCase : Case -> Case = \c -> case c of {
+      Nom => Nom ;
+      _ => Acc 
       } ;
 
     auxVerb : VType -> (VF => Str) = \_ -> haber_V.s ;