2.10.0.M4 build problem

Paul Phillips | 15 Jun 2012 23:36

Re: 2.10.0.M4 build problem

On Fri, Jun 15, 2012 at 2:07 PM, Jason Zaugg <jzaugg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:

AFAICT, you were relying on a bug. I'm not sure exactly when this
changed.

commit 01f6ed8e22d02811fe62b9183d9f84bdda5ede4b

Date: 6 weeks ago

Fix for one of the oldest open soundness bugs.

Closes SI-963, since it was one of my random 30 it won the prize.

The trick after adding the stability check (which has been sitting

there commented out for 3+ years) was that implicit search depended

on the wrongness, because memberWildcardType would create scopes

with members of the form

?{ val name: tp }

And since a def shouldn't match that, fixing it broke everything

until I flipped it around: memberWildcardType should be seeking

?{ def name: tp }

It could also search for a mutable value: the relevant quality

is that it not be stable so it doesn't have a tighter type than

the members it hopes to match.