[Issue 20258] alias this produces an infinite range when used with ranges

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20258

Andrej Mitrovic <andrej.mitrovich at gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|alias this produces an      |alias this produces an
                   |infinite range when used    |infinite range when used
                   |with hashmaps               |with ranges

--- Comment #2 from Andrej Mitrovic <andrej.mitrovich at gmail.com> ---
Simpler example:

-----
import std.stdio;
import std.range;

struct Set
{
    auto walk () { return [].only; }
    alias walk this;
}

void main()
{
    Set set;
    writeln(set);
}
-----

It has to do with ranges, not specifically hashmaps as previously thought.

I think somewhere in the formatter it's probably trying to invoke walk()
multiple times, implicitly through that 'alias this'.

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