https://issues.dlang.org/show_bug.cgi?id=16997

Ketmar Dark <ketmar@ketmar.no-ip.org> changed:

           What    |Removed                     |Added
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                 CC|                            |ketmar@ketmar.no-ip.org

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https://issues.dlang.org/show_bug.cgi?id=16997

--- Comment #1 from ponce <aliloko@gmail.com> ---
Created attachment 1626
  --> https://issues.dlang.org/attachment.cgi?id=1626&action=edit
Patch in ketmar DMD fork ("aliced") to make unary +/- on small integers a
warning

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https://issues.dlang.org/show_bug.cgi?id=16997

Ketmar Dark <ketmar@ketmar.no-ip.org> changed:

           What    |Removed                     |Added
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   Attachment #1626|0                           |1
        is obsolete|                            |

--- Comment #2 from Ketmar Dark <ketmar@ketmar.no-ip.org> ---
Created attachment 1627
  --> https://issues.dlang.org/attachment.cgi?id=1627&action=edit
warning on unary minus/plus

fixed patch, made against vanilla. it will show warning for unary -/+ for
(u)byte and (u)short, but one can silence that with `-(expr)`. it prolly needs
better message with explanation of what it is, and what to do, and why -- but i
leave that for that one who will make a PR out of the patch.

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https://issues.dlang.org/show_bug.cgi?id=16997

--- Comment #3 from Ketmar Dark <ketmar@ketmar.no-ip.org> ---
as for the question: promotion rules are what they are currently to allow this:

byte n;
n = -n;

if unary minus will promote `n`, you will need to add `cast` there. and negate never ever drop bits from integer (even byte.min is essentially unchanged, so no info is lost), so it is -- relatively -- safe to not promote here.

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https://issues.dlang.org/show_bug.cgi?id=16997

--- Comment #4 from Ketmar Dark <ketmar@ketmar.no-ip.org> ---
p.s.: i'm not that smart, tbh, i understood the rationale behind the design after alot of hard thinking.

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https://issues.dlang.org/show_bug.cgi?id=16997

Walter Bright <bugzilla@digitalmars.com> changed:

           What    |Removed                     |Added
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                 CC|                            |bugzilla@digitalmars.com
           See Also|                            |https://issues.dlang.org/sh
                   |                            |ow_bug.cgi?id=17637

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https://issues.dlang.org/show_bug.cgi?id=16997

Walter Bright <bugzilla@digitalmars.com> changed:

           What    |Removed                     |Added
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            Summary|Real-life evidence for      |Integral promotion rules
                   |integer promotion of unary  |not being followed for
                   |minus creating bugs when    |negation expressions
                   |porting C code              |

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https://issues.dlang.org/show_bug.cgi?id=16997

--- Comment #5 from Walter Bright <bugzilla@digitalmars.com> ---
https://github.com/dlang/dmd/pull/7013

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https://issues.dlang.org/show_bug.cgi?id=16997

--- Comment #6 from Walter Bright <bugzilla@digitalmars.com> ---
*** Issue 17637 has been marked as a duplicate of this issue. ***

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https://issues.dlang.org/show_bug.cgi?id=16997

--- Comment #7 from Walter Bright <bugzilla@digitalmars.com> ---
Unary + and unary ~ are also broken in the same way.

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