A common source of churn when we're running experiments is that a module
that would otherwise be valid ends up generating a warning merely because
the experiment is active. That means we end up needing to shuffle the
test files around if the feature ultimately graduates to stable.
To reduce that churn in simple cases, we'll make an exception to disregard
the "Experiment is active" warning for any experiment that a module has
intentionally opted into, because those warnings are always expected and
not a cause for concern.
It's still possible to test those warnings explicitly using the
testdata/warning-files directory, if needed.
This is part of a general effort to move all of Terraform's non-library
package surface under internal in order to reinforce that these are for
internal use within Terraform only.
If you were previously importing packages under this prefix into an
external codebase, you could pin to an earlier release tag as an interim
solution until you've make a plan to achieve the same functionality some
other way.
Martin Atkins