Add tests checking that a number of feature gates are gating their features
Namely:
* `quote`
* `link_args`
* `link_llvm_intrinsics`
* `thread_local`
* `unsafe_destructor`
Also updates test for `plugin_registrar` to make it clear that
it is only testing the `plugin_registrar` feature gate.
Cc #22820. (Latter is not fixed, since there are still a bunch more feature-gates that need tests. But I wanted to stop here and move on to something else.)
This may not be quite ready to go out, I fixed some docs but suspect I missed a bunch.
I also wound up fixing a bunch of redundant `[]` suffixes, but on closer inspection I don't believe that can land until after a snapshot.
Namely:
* `quote`
* `link_args`
* `link_llvm_intrinsics`
* `thread_local`
* `unsafe_destructor`
Also updates test for `plugin_registrar` to make it clear that
it is only testing the `plugin_registrar` feature gate.
Cc #22820.
Motivated by the test output not lining up when it could, I normalized all of the issue-* tests.
While doing it, I found some lexer tests that could be unignored and fixed an int -> isize.
rustc will ICE if you specify an outfile path that is bare without a
directory. As a workaround, before this -o ./foo will work
It wasn't clear to me where I could put a test that actually invokes rustc from a shell, although I think I can add doctests to that machinery in librustc_driver that will arrange for this to be called with arguments that would trigger the ICE
Motivated by the test output not lining up when it could, I normalized all of the issue-* tests.
While doing it, I found some lexer tests that could be unignored and fixed an int -> isize.
This is a hack, but I don't think we can do much better as long as `derive` is running at the syntax expansion phase.
If the `custom_derive` feature gate is enabled, this works with user-defined traits and syntax extensions. Without the gate, you can't use e.g. `#[derive_Clone]` directly, so this does not change the stable language.
To make this effective, we now check gated attributes both before and after macro expansion. This uncovered a number of tests that were missing feature gates.
This PR also cleans up the deriving code somewhat, and forbids some previously-meaningless attribute syntax. For this reason it's technically a
[breaking-change]
r? @sfackler
This is a hack, but I don't think we can do much better as long as `derive` is
running at the syntax expansion phase.
If the custom_derive feature gate is enabled, this works with user-defined
traits and syntax extensions. Without the gate, you can't use e.g. #[derive_Clone]
directly, so this does not change the stable language.
This commit also cleans up the deriving code somewhat, and forbids some
previously-meaningless attribute syntax. For this reason it's technically a
[breaking-change]
since there are separate checks that apply to Copy (and Send uses the
generic defaulted trait rules). Also prohibit `Sized` from being
manually implemented for now.
This concretely improves type inference of some cases (see included
test). I assume the compiler struggles to reason about multiple layers
of generic type parameters (even with associated-type equalities) but
*can* understand pure associated types, since they are always directly
computable from the input types.
Thanks to @shepmaster for noticing the issue with `Cloned` (I took that example as a test case).
Unstable items used in a macro expansion will now always trigger
stability warnings, *unless* the unstable items are directly inside a
macro marked with `#[allow_internal_unstable]`. IOW, the compiler warns
unless the span of the unstable item is a subspan of the definition of a
macro marked with that attribute.
E.g.
#[allow_internal_unstable]
macro_rules! foo {
($e: expr) => {{
$e;
unstable(); // no warning
only_called_by_foo!();
}}
}
macro_rules! only_called_by_foo {
() => { unstable() } // warning
}
foo!(unstable()) // warning
The unstable inside `foo` is fine, due to the attribute. But the
`unstable` inside `only_called_by_foo` is not, since that macro doesn't
have the attribute, and the `unstable` passed into `foo` is also not
fine since it isn't contained in the macro itself (that is, even though
it is only used directly in the macro).
In the process this makes the stability tracking much more precise,
e.g. previously `println!("{}", unstable())` got no warning, but now it
does. As such, this is a bug fix that may cause [breaking-change]s.
The attribute is definitely feature gated, since it explicitly allows
side-stepping the feature gating system.
---
This updates `thread_local!` macro to use the attribute, since it uses
unstable features internally (initialising a struct with unstable
fields).
With this PR in-place constants are handled correctly with respect to debug location assignment.
The PR also adds an (unrelated) test case for debug locations in `extern \"C\"` functions.
Fixes#22432
This commit is an implementation of [RFC 563][rfc] which adds a new
`cfg(debug_assertions)` directive which is specially recognized and calculated
by the compiler. The flag is turned off at any optimization level greater than 1
and may also be explicitly controlled through the `-C debug-assertions`
flag.
[rfc]: https://github.com/rust-lang/rfcs/pull/563
The `debug_assert!` and `debug_assert_eq!` macros now respect this instead of
the `ndebug` variable and `ndebug` no longer holds any meaning to the standard
library.
Code which was previously relying on `not(ndebug)` to gate expensive code should
be updated to rely on `debug_assertions` instead.
Closes#22492
[breaking-change]
Unstable items used in a macro expansion will now always trigger
stability warnings, *unless* the unstable items are directly inside a
macro marked with `#[allow_internal_unstable]`. IOW, the compiler warns
unless the span of the unstable item is a subspan of the definition of a
macro marked with that attribute.
E.g.
#[allow_internal_unstable]
macro_rules! foo {
($e: expr) => {{
$e;
unstable(); // no warning
only_called_by_foo!();
}}
}
macro_rules! only_called_by_foo {
() => { unstable() } // warning
}
foo!(unstable()) // warning
The unstable inside `foo` is fine, due to the attribute. But the
`unstable` inside `only_called_by_foo` is not, since that macro doesn't
have the attribute, and the `unstable` passed into `foo` is also not
fine since it isn't contained in the macro itself (that is, even though
it is only used directly in the macro).
In the process this makes the stability tracking much more precise,
e.g. previously `println!(\"{}\", unstable())` got no warning, but now it
does. As such, this is a bug fix that may cause [breaking-change]s.
The attribute is definitely feature gated, since it explicitly allows
side-stepping the feature gating system.
---
This updates `thread_local!` macro to use the attribute, since it uses
unstable features internally (initialising a struct with unstable
fields).
This commit is an implementation of [RFC 563][rfc] which adds a new
`cfg(debug_assertions)` directive which is specially recognized and calculated
by the compiler. The flag is turned off at any optimization level greater than 1
and may also be explicitly controlled through the `-C debug-assertions`
flag.
[rfc]: https://github.com/rust-lang/rfcs/pull/563
The `debug_assert!` and `debug_assert_eq!` macros now respect this instead of
the `ndebug` variable and `ndebug` no longer holds any meaning to the standard
library.
Code which was previously relying on `not(ndebug)` to gate expensive code should
be updated to rely on `debug_assertions` instead.
Closes#22492
[breaking-change]
