Custom exceptions violate unittest

[Paul Backus]

On Sunday, 30 November 2025 at 14:00:12 UTC, Brother Bill wrote:
> In book "Programming in D", on page 217.
> My concern is why the assertThrown!UnequalLengths unit test 
> does not catch the custom Exception of UnequalLengths.

I just tried building and running your example program with both 
DMD 2.110.0 and LDC 1.40.1, and it worked correctly both times.