(It is not *exactly* the text from the RFC, but the only thing it adds
is a call to a no-op function that is just an attempt to make it clear
where the potential for impl specialization comes from.)
One just checks that we are feature-gating the UGEH attribute (as
usual for attributes associated with unstable features).
The other is adapted from the RFC 1238 text, except that it has been
extended somewhat to actually *illustrate* the scenario that we are
trying to prevent, namely observing the state of data, from safe code,
after the destructor for that data has been executed.
Illustrates cases that worked before and must continue to work, and a
case that shows how to use the `unsafe_destructor_blind_to_params`
attribute (aka "the UGEH attribute") to work around
cannot-assume-parametricity.
I needed it in `RawVec`, `Vec`, and `TypedArena` for `rustc` to
bootstrap; but of course that alone was not sufficient for `make
check`.
Later I added `unsafe_destructor_blind_to_params` to collections, in
particular `LinkedList` and `RawTable` (the backing representation for
`HashMap` and `HashSet`), to get the regression tests exercising
cyclic structure from PR #27185 building.
----
Note that the feature is `dropck_parametricity` (which is not the same
as the attribute's name). We will almost certainly vary our strategy
here in the future, so it makes some sense to have a not-as-ugly name
for the feature gate. (The attribute name was deliberately selected to
be ugly looking.)
The reason this was not failing is fascinating. The variable $(rustc)
is empty, so the make recipe was expanded as " -o foo foo.rs". make
interpreted this as an instruction to run the command "o foo foo.rs"
and ignore any failure that occurred, because it uses a leading '-' on
a command to signal that behavior.
By RFC1214:
> Before calling a fn, we check that its argument and return types are WF.
The previous code only checked the trait-ref, which was not enough
in several cases.
As this is a soundness fix, it is a [breaking-change]. Some new annotations are needed, which I think are because of #18653 and the imperfection of `projection_must_outlive` (that can probably be worked around by moving the wf obligation later).
Fixes#28609
r? @nikomatsakis
The reason this was not failing is fascinating. The variable $(rustc)
is empty, so the make recipe was expanded as " -o foo foo.rs". make
interpreted this as an instruction to run the command "o foo foo.rs"
and ignore any failure that occurred, because it uses a leading '-' on
a command to signal that behavior.
By RFC1214:
Before calling a fn, we check that its argument and return types are WF. This check takes place after all higher-ranked lifetimes have been instantiated. Checking the argument types ensures that the implied bounds due to argument types are correct. Checking the return type ensures that the resulting type of the call is WF.
The previous code only checked the trait-ref, which was not enough
in several cases.
As this is a soundness fix, it is a [breaking-change].
Fixes#28609
This PR closes out #28716 and #28735 by making two changes to the compiler:
1. The `--emit` flag to the compiler now supports the ability to specify the output file name of a partuclar emit type. For example `--emit dep-info=bar.d,asm=foo.s,link` is now accepted.
2. The dep-info emission now emits a dummy target for all input file names to protect against deleted files.
The behavior here isn't really ideal, but we can't really do much better
given the current state of constant evaluation.
The changes to ExprUseVisitor are to avoid a compile error; apparently
that bit of code is extremely sensitive to changes in other areas of the
compiler.
Fixes#28670, and probably a bunch of duplicates.
This commit swaps the order of linking local native libraries and upstream
native libraries on the linker command line. Detail of bugs this can cause can
be found in #28595, and this change also invalidates the test case that was
added for #12446 which is now considered a bug because the downstream dependency
would need to declare that it depends on the native library somehow.
Closes#28595
The behavior here isn't really ideal, but we can't really do much better
given the current state of constant evaluation.
Fixes#28670, and probably a bunch of duplicates.
Currently the compiler supports the ability to emit multiple output types as
part of one compilation (e.g. asm, LLVM IR, bytecode, link, dep-info, etc). It
does not, however, support the ability to customize the output filename for each
of these output types. The `-o` flag is ignored if multiple emit types are
specified (and the compiler emits a warning about this).
Normally this doesn't matter too much, but in the case of `dep-info` it can lead
to a number of problems (e.g. see #28716). By allowing customization of the
output filename for each emit type we're able to solve the problems in that
issue.
This commit adds support for the `--emit` option to the compiler to look like:
rustc foo.rs --emit dep-info=.deps/foo.d,link
This indicates that the `dep-info` output type will be placed at `.deps/foo.d`
and the `link` output type will otherwise be determined via the `--out-dir` and
`-o` flags.
Closes#28716
Travis CI has new infrastructure using the Google Compute Engine which has both
faster CPUs and more memory, and we've been encouraged to switch as it should
help our build times! The only downside currently, however, is that IPv6 is
disabled, causing a number of standard library tests to fail.
Consequently this commit tweaks our travis config in a few ways:
* ccache is disabled as it's not working on GCE just yet
* Docker is used to run tests inside which reportedly will get IPv6 working
* A system LLVM installation is used instead of building LLVM itself. This is
primarily done to reduce build times, but we want automation for this sort of
behavior anyway and we can extend this in the future with building from source
as well if needed.
* gcc-specific logic is removed as the docker image for Ubuntu gives us a
recent-enough gcc by default.
I just removed the num_cpus dependency (because we don't want that in there), using 4 threads instead.
I should add that Veedrac asked me to submit this here in his name.
