Adds more details about how a significant drop in a match scrutinee can
cause a deadlock and include link to documentation. Emits messages
indicating temporaries with significant drops in arms of matches and
message about possible deadlocks/unexpected behavior.
changelog: Add more details to significant drop lint to explicitly show
how temporaries in match scrutinees can cause deadlocks/unexpected
behavior.
When trying to set the current suggestion, if the type of the expression
is not a reference and it is not trivially pure clone copy, we should still
trigger and emit a lint message. Since this fix may require cloning an
expensive-to-clone type, do not attempt to offer a suggested fix.
This change means that matches generated from TryDesugar and AwaitDesugar
would normally trigger a lint, but they are out of scope for this lint,
so we will explicitly ignore matches with sources of TryDesugar or
AwaitDesugar.
changelog: Update for [`significant_drop_in_scrutinee`] to correctly
emit lint messages for cases where the type is not a reference and
not trivially pure clone copy.
