[Issue 14227] Incorrect passed a delegate as argument with null value.

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=14227

--- Comment #1 from Alexey Poryadin <alexey.poryadin at gmail.com> ---
Starting program: /work/research/test 
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Breakpoint 1, test.Class.set() (this=0x7ffff7ed8ff0, callback=..., b=1, a=1) at
/work/research/test.d:7
7            writefln("(callback !is null) %s", (callback !is null));
(gdb) print callback
$1 = {ctxptr = 0x0, funcptr = 0x3ff0000000000000}
(gdb)
-------
This is debug output that I took.

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