D-Programming-Language/dmd — pull request #4182 by 9rnsr (2014-11-29 07:09:21+00:00)
Title: [Refactoring] Fix incorrect wording 'arg' 'argument' for Parameter objects

From the @WalterBright 's comment: https://github.com/D-Programming-Language/dmd/pull/4165#issuecomment-64509292

An exception is the around of TypeTuple. It stores types and expressions
merely using Parameter. So the wording 'arg' is not incorrect at least.