We now include the prelude in so many places, this simplifies how we can
present how `cargo-test-support` works.
Yes, this included some `use` clean ups but its already painful enough
walking through every test file, I didn't want to do it twice.
While this is noisy and hides other deprecations, I figured deprecations would
make it easier for people to discover what tasks remain and allow us to
divide and conquer this work rather than doing a heroic PR.
In theory, this will be short lived and we'll go back to seeing
deprecations in our tests.
When a unit does not have Metadata, the computation of fingerprints
depends on reusing the same fingerprint file to detect if the
output needs to be rebuilt. The previous change that put each unit's
fingerprint into a separate directory was wrong, and broke change
detection in this case (for example, executables on MSVC).
Instead, use a different approach to deal with compiler output caching
by using the same naming convention as the fingerprint file itself.
Generalized `clippy_is_available` and renamed as `command_is_available`.
No checks in `ignores_failure_to_format_source`, it's not supposed to
use `rustfmt` even if it's available
This commit enables pipelined compilation by default in Cargo now that
the requisite support has been stablized in rust-lang/rust#62766. This
involved minor updates in a number of locations here and there, but
nothing of meat has changed from the original implementation (just
tweaks to how rustc is called).
