Static inheritance seems broken

[13k]

Given the file static.lua:

local class = require("middleclass")

local C = class("C")

function C.static:foo()
  return "<static> C.static:foo"
end

function C:initialize()
  self.value = self.class:foo()
end

function C:foo()
  return "<instance> C:foo"
end

local c = C()

print(("[%s] C.static.foo"):format(C.static.foo))
print(("[%s] C.foo"):format(C.foo))
print(("[%s] c.foo"):format(c.foo))
print(("C:foo() = %q"):format(C:foo()))
print(("c:foo() = %q"):format(c:foo()))
print(("c.value = %q"):format(c.value))

local D = class("D", C)

local d = D()

print("---")
print(("[%s] D.static.foo"):format(D.static.foo))
print(("[%s] D.foo"):format(D.foo))
print(("[%s] d.foo"):format(d.foo))
print(("D:foo() = %q"):format(D:foo()))
print(("d:foo() = %q"):format(d:foo()))
print(("d.value = %q"):format(d.value))

And its output:

> lua static.lua 
[function: 0x40cf4998] C.static.foo
[function: 0x40cf4998] C.foo
[function: 0x40cfcf90] c.foo
C:foo() = "<static> C.static:foo"
c:foo() = "<instance> C:foo"
c.value = "<static> C.static:foo"
---
[function: 0x40cfcf90] D.static.foo
[function: 0x40cfcf90] D.foo
[function: 0x40cfcf90] d.foo
D:foo() = "<instance> C:foo"
d:foo() = "<instance> C:foo"
d.value = "<instance> C:foo"

You can see D's static functions addresses all point to C's instance functions and initialization of D's instances calls them, resulting in a wrong d.value (it should be the same as c.value: "<static> C.static:foo").