[Issue 17835] std.algorithm.findSplit: Documentation example does not compile

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=17835

--- Comment #2 from Jon Degenhardt <jrdemail2000-dlang at yahoo.com> ---
(In reply to Duncan Paterson from comment #1)
> Created attachment 1659 [details]
> test case without described behaviour
> 
> I tried to reproduce your issue but couldn't using DMD64 v2.076.0 on mac OS.
> I've attached my test code to ensure I'm testing the same thing you are.

Here's the full test case I used:

--------------------------------
import std.stdio;
import std.algorithm : findSplit;

void main(string[] args)
{
    if (args.length <= 1)
        writeln("Provide an arg with an 'X' in it.");
    else if (const split = args[1].findSplit("X"))
        writefln("Before: '%s'; After: '%s'", split[0], split[2]);
    else
        writefln("No X in '%s'", args[1]);
}
----------------------------------

The 'else if' line generates the compile error. It's the combination of
declaring 'split' const and 'if' invoking the 'bool opCast(T : bool)()'
operator, which is not declared const. Declaring 'split' as auto works fine.
Declaring 'split' const, but not invoking the opCast operator is also fine.

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