diff --git a/builtin/common/strict.lua b/builtin/common/strict.lua
index 05ceadf7..23ba3d72 100644
--- a/builtin/common/strict.lua
+++ b/builtin/common/strict.lua
@@ -5,6 +5,9 @@ local WARN_INIT = false
 
 
 function core.global_exists(name)
+	if type(name) ~= "string" then
+		error("core.global_exists: " .. tostring(name) .. " is not a string")
+	end
 	return rawget(_G, name) ~= nil
 end