1 files changed, 1 insertions, 1 deletions
diff --git a/parser.lua b/parser.lua
index 2ae4aee..4016e9b 100644
--- a/parser.lua
+++ b/parser.lua
@@ -96,7 +96,7 @@ make_parser = function(peg, make_tree)
       file = input
     }
     local tree = peg:match(input, nil, userdata)
-    if not tree then
+    if not tree or type(tree) == 'number' then
       error("File " .. tostring(filename) .. " failed to parse:\n" .. tostring(input))
     end
     return tree