With us moving the required de-duplication up a level, it made this
check redundant. By removing this check, we're more likely to have an
item in the `incls` which forces a smart usage and reduces the chance of
an `[ARGS]` or `[OPTIONS]`, so a couple of tests changed.
Gave up trying to decipher the existing logic for safe ways to
de-duplicate manually and switched to an `IndexSet` to enforce only one
of each argument exists.
Fixes#3556
For some errors, we use the unroll logic to get the list of required
arguments. The usage then does the same, but without a matcher. This
was causing the lists to not match.
As a side effect, this fixed an ordering issue where we were putting the
present arg after the not-present arg. I assume its because we ended up
reporting the items twice but the first time is correctly ordered and
gets precedence.
This was split out of #3020
This is prep for moving the derive tests. Besides organizing the test
folder for each API, this should reduce link time at the cost of
re-compiling more when a test changes.
