[Issue 14232] redundant attribute 'const'

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=14232

--- Comment #17 from Kenji Hara <k.hara.pg at gmail.com> ---
(In reply to Martin Nowak from comment #4)
> (In reply to Ketmar Dark from comment #3)
> > should any bug be deprecated first — just in case somebody wrote invalid
> > code relying on that bug?
> 
> Usually yes, but within reason, depending on how complicated it is to fix
> the code compared to how complicated the deprecation is.

An application of deprecation process will be legitimate only when the
deprecated behavior was valid and designed feature in old versions.

Accepting redundant attributes had not been documented in language spec, it has
been just accidentally accepted. Therefore, consistently disabling them all is
a bugfix. Even though it will break some user code suddenly, deprecation
process should not be applied.

And from a realistic reason, It's difficult. In old dmd version, some of
redundancies were properly disallowed, and remaining were (unintentionally)
accepted. To deprecate invalid accepted case, we should emulate old
unintentional compiler behavior. It's too costly, and I don't want to do it.

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