Deprecate alias this for classes v2

[RazvanN7]

No description provided.

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Testing this PR locally

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dub run digger -- build "master + dmd#14812"

[RazvanN7]

cc @Geod24

[RazvanN7]

cc @WalterBright

[benjones]

Wow, the only buildkite failures are phobos!

[thewilsonator]

Changelog entry

[pbackus]

Should this include interfaces too?

[RazvanN7]

I had no idea you could use alias this in interfaces. Yes, definitely, interfaces should be included too.

[RazvanN7]

@thewilsonator added changelog entry
@pbackus included interfaces

[RazvanN7]

The GDC tester fails with:

src/dmd/dtoh.d:294:12: error: declaration expected, not 'foreach'
  294 |     static foreach(member; __traits(allMembers, Context))
      |            ^
src/dmd/dtoh.d:294:28: error: declaration expected, not '__traits'
  294 |     static foreach(member; __traits(allMembers, Context))
      |                            ^
src/dmd/dtoh.d:3037:1: error: unrecognized declaration
 3037 | }
      | ^

when trying to build the compiler. @ibuclaw does gdc not recognize static foreach?

Later edit: It seems that gdc-10 does recognize static foreach, maybe the tester uses an older version?

[adamdruppe]

gdc added static foreach i think in version 10. Version 9 and below do not have it.

You can make a helper function concat the strings and return them in one go for a use like this to be compatible with more ocmpailers.

[RazvanN7]

gdc added static foreach i think in version 10. Version 9 and below do not have it.

Yeah, I just consulted the changelog: https://gcc.gnu.org/gcc-10/changes.html (ctrl-f "static foreach").

Is anything preventing us from upgrading the tester to gdc10?

[ibuclaw]

gdc added static foreach i think in version 10. Version 9 and below do not have it.

Yeah, I just consulted the changelog: https://gcc.gnu.org/gcc-10/changes.html (ctrl-f "static foreach").

Is anything preventing us from upgrading the tester to gdc10?

Yes, me. Don't break gdc's bootstrap, else I'll revert.

[RazvanN7]

Spec PR: dlang/dlang.org#3498

[ibuclaw]

There's more deprecated messages when running the testsuite:

testsuite/libphobos.hash/test_hash.d:293: warning: alias this for classes/interfaces is deprecated
testsuite/libphobos.hash/test_hash.d:300: warning: alias this for classes/interfaces is deprecated 

These excess warnings breaks the testsuite.