Better error messages - from reddit

[H. S. Teoh]

On Mon, Mar 04, 2019 at 11:03:28PM +0000, Adam D. Ruppe via Digitalmars-d wrote:
> On Monday, 4 March 2019 at 15:47:12 UTC, H. S. Teoh wrote:
> > This is why I'm starting to think sig constraints are not the genius
> > idea they first appeared to be.
> 
> If the implementation actually told you which individual pieces failed
> (and perhaps even why), I don't think we'd be worried about this.
[....]
> Imagine what we'd say if the error message was not:
[...]
> but rather
> 
> 
> 
> ooooo.d(4): Error: template std.algorithm.sorting.sort cannot deduce
> function from argument types
>    !()(FilterResult!(unaryFun, int[])), candidates are:
> /home/me/d/dmd2/linux/bin32/../../src/phobos/std/algorithm/sorting.d(1847):
>    std.algorithm.sorting.sort([collapsed])(Range r)
>       if (
>         // passed
>         (ss == SwapStrategy.unstable &&
>         // passed
>         (hasSwappableElements!Range || hasAssignableElements!Range) ||
>          // short-circuited
>         ss != SwapStrategy.unstable &&
> asAssignableElements!Range)
>         // ******* FAILED ***********
>         && isRandomAccessRange!Range
>         // short-circuited, but would fail
>         && hasSlicing!Range && hasLength!Range
>       )
> 
> 
> That tells you everything you need to know.

Yes, this is indeed a big improvement over what we currently have.  It
may not be perfect, but it goes a long way from where we are right now.
Also, it should be relatively straightforward to implement, and doesn't
break any existing code, etc..

Where's the PR for this??? I want it NAO! :-D


T

-- 
A mathematician is a device for turning coffee into theorems. -- P. Erdos