diff options
| -rw-r--r-- | toplevel/metasyntax.ml | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/toplevel/metasyntax.ml b/toplevel/metasyntax.ml index d0893107a..d41ce2803 100644 --- a/toplevel/metasyntax.ml +++ b/toplevel/metasyntax.ml @@ -529,6 +529,8 @@ let rec merge_entry_types etyps' = function let set_entry_type etyps (x,typ) = let typ = try match List.assoc x etyps, typ with + | _, (_,BorderProd (true,_)) -> + error "The level of the leftmost non-terminal cannot be changed" | ETConstr (n,()), (_,BorderProd (left,_)) -> ETConstr (n,BorderProd (left,None)) | ETConstr (n,()), (_,InternalProd) -> ETConstr (n,InternalProd) |