diff --git a/script/parser/luadoc.lua b/script/parser/luadoc.lua
index 1a777be19..6d9bad0d6 100644
--- a/script/parser/luadoc.lua
+++ b/script/parser/luadoc.lua
@@ -417,6 +417,9 @@ local function parseTuple(parent)
             }
             index          = index + 1
             field.extends  = parseType(field)
+            if not field.extends then
+                break
+            end
             field.optional = field.extends.optional
             field.start    = field.extends.start
             field.finish   = field.extends.finish