-transition=intpromote deprecation message confusing

[dlangBugzillaToGithub]

Timothee Cour (@timotheecour) reported this on 2018-01-26T21:40:49Z

Transferred from https://issues.dlang.org/show_bug.cgi?id=18307

CC List

• Zach the Mystic

Description

see https://github.com/msgpack/msgpack-d/pull/99/files/728edb1d58c8e027adf5740e3fbcf425639710c4#r164228277 for context.

dmd.2_078_1/.dub/packages/msgpack-d-1.0.0-beta.6/msgpack-d/src/msgpack/unpacker.d(199,30): Deprecation: integral promotion not done for -header, use '-transition=intpromote' switch or -cast(int)(header)

* should that be -int(header) instead of -cast(int)(header) ?
* could dmd also report the type of `header` since it already knows about it?

[dlangBugzillaToGithub]

reachzach commented on 2018-04-15T02:48:20Z

I tested it and this works:

// change this:
// value = -(cast(T)-header);

// to this:
value = cast(T)cast(byte)header;

header is a ubyte. When changed to a byte, in this context, it becomes negative. The compiler then creates a corresponding negative int.

[dlangBugzillaToGithub]

reachzach commented on 2018-04-15T02:50:14Z

...or whatever negative Integral type it requires. (I did only test it with `int`, but I think it should work regardless.