import exception2;
void main() {
        int a;

        try {
		// string error type instead of namespaced D type
		// can still attach information though
                throw Exception2!"foo bar"(a);
        } catch(Exception2!"foo bar") { // caught by string
               // printing it here would show the value of `a`
        }
}

Read more at the link:
http://dpldocs.info/this-week-in-d/Blog.Posted_2022_08_01.html

On Monday, 1 August 2022 at 23:04:57 UTC, Adam D Ruppe wrote:

import exception2;
void main() {
        int a;

        try {
		// string error type instead of namespaced D type
		// can still attach information though
                throw Exception2!"foo bar"(a);
        } catch(Exception2!"foo bar") { // caught by string
               // printing it here would show the value of `a`
        }
}

It won't play well with autocomplete :(.