Workaround rust-lang/rust#49855 by forcing rustc_error in any mode, including NLL.

NOTE: I was careful to make each change in a manner that preserves the
existing diagnostic output (usually by ensuring that no lines were
added or removed). This means that the resulting source files are not
as nice to read as they were at the start. But we will have to review
these cases by hand anyway as follow-up work, so cleanup could
reasonably happen then (or not at all).

0 files changed, 0 insertions, 0 deletions