[OT] The Usual Arithmetic Confusions

[Nick Treleaven]

On Friday, 18 February 2022 at 04:32:56 UTC, Walter Bright wrote:
>     ptrdiff_t len = array.length;

The problem is remembering to do that, particularly in cases 
where the unsigned value is an inferred function result, or for 
an index involving $.

We need an error, not an implicit conversion. I expect you to say 
that will force users to cast, which can introduce bugs if the 
source type changes. The solution to that is to encourage using 
e.g. std.conv.signed:
https://dlang.org/library/std/conv/signed.html