New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Why EitherT is not covariant for the input types as Either from scala #2538

Closed
REASY opened this Issue Sep 27, 2018 · 3 comments

Comments

Projects
None yet
2 participants
@REASY
Copy link

REASY commented Sep 27, 2018

No description provided.

@ceedubs

This comment has been minimized.

Copy link
Member

ceedubs commented Sep 29, 2018

This has been discussed in #2310 and #556. I'm going to leave this issue open, because the fact that it keeps coming up is a sign that we really need to document this. I'll try to put something together.

ceedubs added a commit to ceedubs/typelevel.github.com that referenced this issue Sep 30, 2018

Add a blog post aboutn variance and monad transformers
Every once in a while [people](typelevel/cats#556) [ask](typelevel/cats#2310) [about](typelevel/cats#2538) this.

I thought that it would be nice to provide a more detailed answer in a
single place so we can link to it from the Cats FAQ.

Note: I had to add the `-Ypartial-unification` flag for one of the code
samples to compile. It's quite possible that I should be doing this a
different way than I did.

ceedubs added a commit to ceedubs/typelevel.github.com that referenced this issue Sep 30, 2018

Add a blog post about variance and monad transformers
Every once in a while [people](typelevel/cats#556) [ask](typelevel/cats#2310) [about](typelevel/cats#2538) this.

I thought that it would be nice to provide a more detailed answer in a
single place so we can link to it from the Cats FAQ.

Note: I had to add the `-Ypartial-unification` flag for one of the code
samples to compile. It's quite possible that I should be doing this a
different way than I did.
@ceedubs

This comment has been minimized.

Copy link
Member

ceedubs commented Sep 30, 2018

I've submitted typelevel/typelevel.github.com#233 and if it gets merged we can point to the blog post in the Cats FAQ.

ceedubs added a commit to ceedubs/cats that referenced this issue Oct 1, 2018

@ceedubs ceedubs closed this in #2549 Oct 1, 2018

@REASY

This comment has been minimized.

Copy link

REASY commented Oct 2, 2018

Thanks, @ceedubs !

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment