diff --git a/gen/intellij/haskell/parser/HaskellParser.java b/gen/intellij/haskell/parser/HaskellParser.java
index f9bea9ad..2a84789d 100644
--- a/gen/intellij/haskell/parser/HaskellParser.java
+++ b/gen/intellij/haskell/parser/HaskellParser.java
@@ -632,7 +632,7 @@ public class HaskellParser implements PsiParser, LightPsiParser {
   }
 
   /* ********************************************************** */
-  // (atype | TILDE | UNDERSCORE)+
+  // (atype | TILDE | UNDERSCORE | VERTICAL_BAR)+
   static boolean btype(PsiBuilder b, int l) {
     if (!recursion_guard_(b, l, "btype")) return false;
     boolean r;
@@ -647,13 +647,14 @@ public class HaskellParser implements PsiParser, LightPsiParser {
     return r;
   }
 
-  // atype | TILDE | UNDERSCORE
+  // atype | TILDE | UNDERSCORE | VERTICAL_BAR
   private static boolean btype_0(PsiBuilder b, int l) {
     if (!recursion_guard_(b, l, "btype_0")) return false;
     boolean r;
     r = atype(b, l + 1);
     if (!r) r = consumeToken(b, HS_TILDE);
     if (!r) r = consumeToken(b, HS_UNDERSCORE);
+    if (!r) r = consumeToken(b, HS_VERTICAL_BAR);
     return r;
   }
 
diff --git a/src/main/scala/intellij/haskell/haskell.bnf b/src/main/scala/intellij/haskell/haskell.bnf
index 5d0d30d3..29a8ec61 100644
--- a/src/main/scala/intellij/haskell/haskell.bnf
+++ b/src/main/scala/intellij/haskell/haskell.bnf
@@ -186,7 +186,7 @@ ttype2                      ::= ("forall" | FORALL)? onl ttype (onl DOUBLE_RIGHT
 
 ttype                       ::= "!"? (btype (oonls RIGHT_ARROW oonls ttype)* | list_type q_name* | LEFT_PAREN RIGHT_ARROW RIGHT_PAREN)
 
-private btype               ::= (atype | TILDE | UNDERSCORE)+     // generalization because left recursive is not supported and UNDERSCORE because of partial type signatures
+private btype               ::= (atype | TILDE | UNDERSCORE | VERTICAL_BAR)+     // generalization because left recursive is not supported and UNDERSCORE because of partial type signatures
 
 simpletype                  ::= ttype | (q_name | LEFT_PAREN RIGHT_PAREN)+ |
                                   q_name* oonls LEFT_PAREN q_name RIGHT_PAREN oonls q_name* |