It'll only group them together if they happen from the same line of code, so it's not too too bad.

Happy to think about ways of making this better. From past experience just using the message is terrible, as messages are too unique so you end up with the opposite problem.

Going to close this, as I think the best way is just to use a custom error type.

In case someone else gets to here because grouping is too broad, the key ingredient for correct grouping is to set ProjectPackages in your configuration to a suitable value (e.g. []string{"github.com/yourco/yourproj/**"}) as the grouping goes by the top most line that's in-project, but if it finds nothing in-project it will just use the top line which is likely something like

runtime/panic.go:489 gopanic

(or maybe it just skips the top file:line and uses the error class exclusively?)

making everything sharing an error class group together.