Overloading by a local proc affected by code in other blocks

[bluenote10]

An issue I discovered while testing this PR. Apparently, the issue is unrelated to the PR, and I couldn't find an existing issue for that. The problem is that overloading by a local proc does work in this example:

import tables
from hashes import THash

block:
  proc hash(x: int): THash {.inline.} =
    echo "overloaded hash"
    result = x

  var t = initTable[int, int]()
  t[0] = 0 # will call the overloaded hash

But if I add another (supposedly unrelated) code block, I can no longer use the overloaded function:

import tables
from hashes import THash

block:
  var t = initTable[int,int]()
  t[0] = 42 # comment this line and it works again!

block:
  proc hash(x: int): THash {.inline.} =
    echo "overloaded hash"
    result = x

  var t = initTable[int, int]()
  t[0] = 0 # now, this no longer calls the overloaded hash!

[dom96]

This looks very subtle so I will make it High Priority, feel free to change that @Araq.

[Araq]

This is not supported properly. Instead we cache the instantiation of 'Table[int, int]' to reduce code sizes. Not sure how to solve this.

[metagn]

Currently the overload doesn't load at all unless it's top level. Issue can be closed?