This is a common mistake made more common be suggestions of existing diagnostic
that tell users not to use a 'copy' dependency.
Report a diagnostic error rather than crashing the compiler. Fix the diagnostic
output to make sense relative to the source location.
Fixes rdar://154136015 ([nonescapable] compiler assertion with @_lifetime(x: inout x))
(cherry picked from commit 080b68292d)
Find all the usages of `--enable-experimental-feature` or
`--enable-upcoming-feature` in the tests and replace some of the
`REQUIRES: asserts` to use `REQUIRES: swift-feature-Foo` instead, which
should correctly apply to depending on the asserts/noasserts mode of the
toolchain for each feature.
Remove some comments that talked about enabling asserts since they don't
apply anymore (but I might had miss some).
All this was done with an automated script, so some formatting weirdness
might happen, but I hope I fixed most of those.
There might be some tests that were `REQUIRES: asserts` that might run
in `noasserts` toolchains now. This will normally be because their
feature went from experimental to upcoming/base and the tests were not
updated.
