status of mtl

[Henning Thielemann]

On Thu, 30 Sep 2021, Ben Franksen wrote:

> The burden lies with those who want to use the new features: they need 
> to convince other library maintainers to release compatibility updates 
> with raised upper bounds on their mtl dependency, issuing PRs and 
> lobbying for new releases. This is exactly as it should be.

If I do not relax the version bounds of my Build-Depends on mtl then my 
library gets outdated and other people who want to use new mtl features 
are blocked by my library.

Actually, if a new major mtl version is released, then Stackage notifies 
all transitively dependent packages and if authors do not update their 
dependent libraries then the affected packages are kicked off from the 
Stack package set.