Remove deprecated features

[frangio]

There are various deprecated functions that need to be removed in the next major version. These are annotated in the docs such as:

openzeppelin-contracts/contracts/access/AccessControl.sol

Line 203 in c1d9da4

* NOTE: This function is deprecated in favor of {_grantRole}.

We should search and remove all of these.

A list, not necessarily exhaustive:

• Deprecated contracts
  • GovernorProposalThreshold
  • ERC777
• Deprecated draft-*.sol files:
  • draft-IERC2612.sol
  • draft-ERC20Permit.sol
  • draft-IERC20Permit.sol
  • draft-ERC721Votes.sol
  • draft-EIP712.sol
• Deprecated functions
  • SafeMath.sol: function that need use memory for the error reason
  • EnumerableMap.sol: function that need use memory for the error reason
  • AccessControl.sol: _setupRole
  • BeaconProxy.sol: _setBeacon
• Deprecated state variables
  • GovernorCompatibilityBravo.ProposalDetails.proposer (not deprecated but not needed since we have Governor.ProposalCore.proposer)
  • GovernorVotesQuorumFraction._quorumNumerator

[akshaysrivastav]

While those functions are marked as deprecated, they are still used in other OZ contracts.
Like here: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/presets/ERC20PresetMinterPauser.sol#L39-L42

Wouldn't it be sensible to remove the usage of deprecated functions in a minor release first?

[Amxx]

Wouldn't it be sensible to remove the usage of deprecated functions in a minor release first?

We want to guarantee a smooth upgrade between minor releases. This means we don't want to do any breaking changes (such as removing a function) in a minor.

That is what majors are for: making breaking change and removing things we want to stop supporting.

Also note that removing the preset is part of the planned breaking changes for 5.0

[ernestognw]

Closed by #4258