Can't call an internal function from constructor

[banteg]

Version Information

• vyper Version (output of vyper --version): 0.2.8
• OS: osx
• Python Version (output of python --version): 3.8.2
• Environment (output of pip freeze):

What's your issue about?

@internal
def initialize():
    ...

@external
def __init__():
    self.initialize()

Compiling contracts...
  Vyper version: 0.2.8
Unhandled exception in 'contracts/Vault.vy':
FunctionDeclarationException: Function not declared yet (reminder: functions cannot call functions later in code than themselves): initialize

How can it be fixed?

Allow calling internal functions from constructor.

[fubuloubu]

Solution is to inline the internal method into the deployment constructor. This is useful for being able to deploy proxies

[charles-cooper]

I believe this is a dup of #1631