-preview=in might break code

[Andrei Alexandrescu]

On 10/2/20 10:08 AM, Steven Schveighoffer wrote:
> Is there a way to prevent this?
> 
> import std.stdio;
> struct S(size_t elems)
> {
>      int[elems] data;
> }
> 
> void foo(T)(in T constdata, ref T normaldata)
> {
>      normaldata.data[0] = 1;
>      writeln(constdata.data[0]);
> }
> void main()
> {
>      S!1 smallval;
>      foo(smallval, smallval);
>      S!100 largeval;
>      foo(largeval, largeval);
> }
> 
> 
> Compile without -preview=in, it prints:
> 
> 0
> 0
> 
> Compile with -preview=in, it prints:
> 
> 0
> 1

Finally, my "told you so" moment has come! :o)

https://forum.dlang.org/post/rhmst4$1vmc$1@digitalmars.com