diff --git a/nattlua/hash_type.lua b/nattlua/hash_type.lua
new file mode 100644
index 000000000..b8acd020d
--- /dev/null
+++ b/nattlua/hash_type.lua
@@ -0,0 +1,186 @@
+local table_sort = table.sort
+local table_concat = table.concat
+local hash_type
+local sort = function(a--[[#: string]], b--[[#: string]])
+	return a < b
+end
+
+local function hash_tuple(self)
+	if self.suppress_hash then return "current_tuple" end
+
+	self.suppress_hash = true
+	local strings--[[#: List<|string|>]] = {}
+
+	for i, v in ipairs(self:GetData()) do
+		strings[i] = hash_type(v)
+	end
+
+	if self.Remainder then table.insert(strings, hash_type(self.Remainder)) end
+
+	local s = "("
+
+	if #strings == 1 and strings[1] then
+		s = s .. strings[1] .. ","
+	else
+		s = s .. table.concat(strings, ", ")
+	end
+
+	s = s .. ")"
+
+	if self.Repeat then s = s .. "*" .. tostring(self.Repeat) end
+
+	self.suppress_hash = false
+	return s
+end
+
+local function hash_union(self)
+	if self.suppress_hash then return "current_union" end
+
+	local s = {}
+	self.suppress_hash = true
+
+	for i, v in ipairs(self.Data) do
+		s[i] = hash_type(v)
+	end
+
+	if not s[1] then
+		self.suppress_hash = false
+		return "|"
+	end
+
+	self.suppress_hash = false
+
+	if #s == 1 then return (s[1]--[[# as string]]) .. "|" end
+
+	table_sort(s, sort)
+	return table_concat(s, " | ")
+end
+
+local function hash_table(self)
+	if self:GetContract() and self:GetContract().Name then
+		return "TABLE-NAME-" .. self:GetContract().Name:GetData()
+	end
+
+	if self.Name then return "TABLE-NAME-" .. self.Name:GetData() end
+
+	if self:IsUnique() then return tostring(self:GetUniqueID()) end
+
+	if self.suppress_hash then return "current_table" end
+
+	self.suppress_hash = true
+	local s = {}
+	local contract = self:GetContract()
+
+	if contract and contract.Type == "table" and contract ~= self then
+		for i, keyval in ipairs(contract:GetData()) do
+			local key = self:GetData()[i] and hash_type(self:GetData()[i].key) or "nil"
+			local val = self:GetData()[i] and hash_type(self:GetData()[i].val) or "nil" -- TOOD: ?? 
+			local tkey, tval = hash_type(keyval.key), hash_type(keyval.val)
+
+			if key == tkey then
+				s[i] = "[" .. key .. "]"
+			else
+				s[i] = "[" .. key .. " as " .. tkey .. "]"
+			end
+
+			if val == tval then
+				s[i] = s[i] .. " = " .. val
+			else
+				s[i] = s[i] .. " = " .. val .. " as " .. tval
+			end
+		end
+	else
+		for i, keyval in ipairs(self:GetData()) do
+			local key = hash_type(keyval.key)
+			local val = hash_type(keyval.val)
+			s[i] = "[" .. key .. "]" .. " = " .. val
+		end
+	end
+
+	self.suppress_hash = false
+	table_sort(s, sort)
+
+	if #self:GetData() <= 1 then return "{" .. table.concat(s, ",") .. " }" end
+
+	return "{" .. table.concat(s, ",") .. "}"
+end
+
+local function hash_string(self)
+	if self.Data then return "STRING-" .. self.Data end
+
+	return "string"
+end
+
+local function hash_number(self)
+	if self:IsNan() then return "nan" end
+
+	if self.Data then
+		if self.Max then
+			if self.Max ~= false and self.Data then
+				return tostring(self.Data) .. "-" .. tostring(self.Max)
+			end
+		end
+
+		return tostring(self.Data)
+	end
+
+	return "number"
+end
+
+local function hash_function(self)
+	return "function=" .. hash_type(self:GetInputSignature()) .. ">" .. hash_type(self:GetOutputSignature())
+end
+
+local function hash_any(self)
+	return "any"
+end
+
+local function hash_symbol(self)
+	if self:IsTrue() then
+		return "true"
+	elseif self:IsFalse() then
+		return "false"
+	elseif self:IsNil() then
+		return "nil"
+	end
+
+	return tostring(self:GetData())
+end
+
+function hash_type(obj)
+	if type(obj) ~= "table" or obj.Type == nil then
+		print(obj)
+		error(debug.traceback("wtf"))
+	end
+
+	if obj.Type == "union" then
+		return hash_union(obj)
+	elseif obj.Type == "tuple" then
+		return hash_tuple(obj)
+	elseif obj.Type == "table" then
+		return hash_table(obj)
+	elseif obj.Type == "string" then
+		return hash_string(obj)
+	elseif obj.Type == "number" then
+		return hash_number(obj)
+	elseif obj.Type == "any" then
+		return "any" -- this is wrong?
+	elseif obj.Type == "symbol" then
+		return tostring(obj)
+	elseif obj.Type == "function" then
+		return hash_function(obj)
+	end
+
+	error("NYI type " .. obj.Type)
+end
+
+return function(obj)
+	local res = hash_type(obj)
+
+	if type(res) ~= "string" then
+		print(obj)
+		error("INVALID RETURN TYPE: " .. type(res))
+	end
+
+	return res
+end
diff --git a/nattlua/types/table.lua b/nattlua/types/table.lua
index 08e196be0..a4c1bfebb 100644
--- a/nattlua/types/table.lua
+++ b/nattlua/types/table.lua
@@ -75,35 +75,37 @@ function META:GetSelf2()
 end
 
 function META.Equal(a--[[#: TBaseType]], b--[[#: TBaseType]])
-	if a.Type ~= b.Type then return false end
+	if a.Type ~= b.Type then return false, "type mismatch" end
 
-	if a:IsUnique() then return a:GetUniqueID() == b:GetUniqueID() end
+	if a:IsUnique() then return a:GetUniqueID() == b:GetUniqueID(), "uid eq/neq" end
 
 	if a:GetContract() and a:GetContract().Name then
 		if not b:GetContract() or not b:GetContract().Name then
 			a.suppress = false
-			return false
+			return false,
+			"a has contract .Name but b does not have contract or contract .Name"
 		end
 
 		-- never called
 		a.suppress = false
-		return a:GetContract().Name:GetData() == b:GetContract().Name:GetData()
+		return a:GetContract().Name:GetData() == b:GetContract().Name:GetData(),
+		".Name mismatch"
 	end
 
 	if a.Name then
 		a.suppress = false
 
-		if not b.Name then return false end
+		if not b.Name then return false, "a has .Name but b does not have .Name" end
 
 		return a.Name:GetData() == b.Name:GetData()
 	end
 
-	if a.suppress then return true end
+	if a.suppress then return true, "suppress" end
 
 	local adata = a:GetData()
 	local bdata = b:GetData()
 
-	if #adata ~= #bdata then return false end
+	if #adata ~= #bdata then return false, "#.Data mismatch" end
 
 	for i = 1, #adata do
 		local akv = adata[i]
@@ -120,11 +122,33 @@ function META.Equal(a--[[#: TBaseType]], b--[[#: TBaseType]])
 
 		if not ok then
 			a.suppress = false
-			return false
+			return false, "value mismatch "
 		end
 	end
 
-	return true
+	return true, "all is ok"
+end
+
+local old = META.Equal
+local hash_type = require("nattlua.hash_type")--[[# as any]]
+
+function META.Equal(a--[[#: TBaseType]], b--[[#: TBaseType]])
+	local b1, reason = old(a, b)
+	local b2 = hash_type(a) == hash_type(b)
+
+	if b1 ~= b2 then
+		print("================")
+		print("tables should " .. (b1 and "be equal" or "NOT be equal") .. " :")
+		print(reason)
+		print("\t", hash_type(a), " != ", hash_type(b))
+		print("A:")
+		print("\t", a, a:GetContract(), a:GetName(), a:GetUniqueID(), #a.Data, a.suppress)
+		print("B:")
+		print("\t", b, b:GetContract(), b:GetName(), b:GetUniqueID(), #b.Data, b.suppress)
+		print("================")
+	end
+
+	return b1
 end
 
 local level = 0
diff --git a/nattlua/types/union.lua b/nattlua/types/union.lua
index f4d6f8f14..dd0bf2da0 100644
--- a/nattlua/types/union.lua
+++ b/nattlua/types/union.lua
@@ -45,9 +45,7 @@ function META.Equal(a--[[#: TUnion]], b--[[#: TBaseType]])
 		local a = a.Data[i]--[[# as TBaseType]]
 		local ok = false
 
-		if a.Type == "union" or a.Type == "table" then
-			a.suppress = true--[[# as boolean]]
-		end
+		if a.Type == "union" then a.suppress = true--[[# as boolean]] end
 
 		for i = 1, len do
 			local b = b.Data[i]--[[# as TBaseType]]
@@ -56,9 +54,7 @@ function META.Equal(a--[[#: TUnion]], b--[[#: TBaseType]])
 			if ok then break end
 		end
 
-		if a.Type == "union" or a.Type == "table" then
-			a.suppress = false--[[# as boolean]]
-		end
+		if a.Type == "union" then a.suppress = false--[[# as boolean]] end
 
 		if not ok then return false end
 	end