resolve: Make "empty import canaries" invisible from other crates
Empty imports `use prefix::{};` are desugared into `use prefix::{self as _};` to make sure the prefix is checked for privacy/stability/etc.
This caused issues in cross-crate scenarios because gensyms are lost in crate metadata (the `_` is a gensym).
Fixes https://github.com/rust-lang/rust/issues/55811
Allow #[must_use] on traits
Addresses https://github.com/rust-lang/rust/issues/55506, but we'll probably want to add it to some library traits like `Iterator` before the issue is considered fixed. Fixes https://github.com/rust-lang/rust/issues/51560.
`#[must_use]` is already permitted on traits, with no effect, so this seems like a bug fix, but I might be overlooking something. This currently warns for `impl Trait` or `dyn Trait` when the `Trait` is `#[must_use]` (although I don't think the latter is currently possible, so it's simply future-proofed).
Fix stability hole with `static _`
The `underscore_const_names` only gated const items with `_` as the name.
`static _: () = ();` works on beta without feature gates right now, this PR fixes that.
Rollup of 25 pull requests
Successful merges:
- #55562 (Add powerpc- and powerpc64-unknown-linux-musl targets)
- #55564 (test/linkage-visibility: Ignore on musl targets)
- #55827 (A few tweaks to iterations/collecting)
- #55834 (Forward the ABI of the non-zero sized fields of an union if they have the same ABI)
- #55857 (remove unused dependency)
- #55862 (in which the E0618 "expected function" diagnostic gets a makeover)
- #55867 (do not panic just because cargo failed)
- #55894 (miri enum discriminant handling: Fix treatment of pointers, better error when it is undef)
- #55916 (Make miri value visitor useful for mutation)
- #55919 (core/tests/num: Simplify `test_int_from_str_overflow()` test code)
- #55923 (reword #[test] attribute error on fn items)
- #55949 (ty: return impl Iterator from Predicate::walk_tys)
- #55952 (Update to Clang 7 on CI.)
- #55953 (#53488 Refactoring UpvarId)
- #55962 (rustdoc: properly calculate spans for intra-doc link resolution errors)
- #55963 (Stress test for MPSC)
- #55968 (Clean up some non-mod-rs stuff.)
- #55970 (Miri backtrace improvements)
- #56007 (CTFE: dynamically make sure we do not call non-const-fn)
- #56011 (Replace data.clone() by Arc::clone(&data) in mutex doc.)
- #56012 (avoid shared ref in UnsafeCell::get)
- #56016 (Add VecDeque::resize_with)
- #56027 (docs: Add missing backtick in object_safety.rs docs)
- #56043 (remove "approx env bounds" if we already know from trait)
- #56059 (Increase `Duration` approximate equal threshold to 1us)
Increase `Duration` approximate equal threshold to 1us
Previously this threshold when testing was 100ns, but the Windows
documentation states:
> which is a high resolution (<1us) time stamp
which presumably means that we could have up to 1us resolution, which
means that 100ns doesn't capture "equivalent" time intervals due to
various bits of rounding here and there.
It's hoped that this..
Closes#56034
remove "approx env bounds" if we already know from trait
Alternative to https://github.com/rust-lang/rust/pull/55988 that fixes#55756 -- smaller fix that I cannot see having (correctness) repercussions beyond the test at hand, and hence better for backporting. (Famous last words, I know.)
r? @eddyb
CTFE: dynamically make sure we do not call non-const-fn
I'd love to have a test case for this, but I don't know how.
I am also really surprised by this test case that changed behavior: Why did it even start execution if it already determined that it shouldn't?!?
r? @oli-obk
Miri backtrace improvements
Nicer pretty-printing of the `RUST_CTFE_BACKTRACE`-backtraces:
```
0: backtrace::backtrace::libunwind::trace::hc410fcb66fe85b11
at /home/r/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.9/src/backtrace/libunwind.rs:53
backtrace::backtrace::trace::h2106294a22648407
at /home/r/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.9/src/backtrace/mod.rs:42
1: backtrace::capture::Backtrace::new_unresolved::h5d8d98b993d092ba
at /home/r/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.9/src/capture.rs:88
2: <rustc::mir::interpret::error::EvalError<'tcx> as core::convert::From<rustc::mir::interpret::error::EvalErrorKind<'tcx, u64>>>::from::h6355269b2a661412
at librustc/mir/interpret/error.rs:236
3: <T as core::convert::Into<U>>::into::h70fcb917509539bd
at /home/r/src/rust/rustc.2/src/libcore/convert.rs:455
4: <rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, miri::Evaluator<'tcx>> as miri::fn_call::EvalContextExt<'tcx, 'mir>>::emulate_foreign_item::h9cde0e3ce7455a4a
at src/fn_call.rs:292
5: <rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, miri::Evaluator<'tcx>> as miri::fn_call::EvalContextExt<'tcx, 'mir>>::find_fn::h83f89524b9d1a49a
at src/fn_call.rs:74
6: <miri::Evaluator<'tcx> as rustc_mir::interpret::machine::Machine<'a, 'mir, 'tcx>>::find_fn::hf9980473c4775f0c
at src/lib.rs:345
rustc_mir::interpret::terminator::<impl rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, M>>::eval_fn_call::h401dec4a687f96e9
at /home/r/src/rust/rustc.2/src/librustc_mir/interpret/terminator.rs:285
```
Indentation is now consistent with `RUST_BACKTRACE`, and the frame number is not repeated when there are multiple symbols for a frame.
Also preserve the `ty::Instance` for the internal backtrace (showing which frames in the user code where on the interpreter stack when the error happened), used by miri to avoid printing spans for libstd internals:
```
error[E0080]: constant evaluation error: the evaluated program panicked
--> /home/r/src/rust/rustc.2/src/libstd/panicking.rs:525:9
|
525 | __rust_start_panic(obj as usize)
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked
|
= note: inside call to `std::panicking::rust_panic` at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:496:5
= note: inside call to `std::panicking::rust_panic_with_hook` at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:390:5
= note: inside call to `std::panicking::continue_panic_fmt` at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:345:5
note: inside call to `std::rt::begin_panic_fmt` at <::std::macros::panic macros>:8:1
--> tests/compile-fail/panic.rs:4:5
|
4 | assert_eq!(5, 6);
| ^^^^^^^^^^^^^^^^^
= note: inside call to `main` at /home/r/src/rust/rustc.2/src/libstd/rt.rs:74:34
= note: inside call to closure at /home/r/src/rust/rustc.2/src/libstd/rt.rs:59:75
= note: inside call to closure at /home/r/src/rust/rustc.2/src/libstd/sys_common/backtrace.rs:136:5
= note: inside call to `std::sys_common::backtrace::__rust_begin_short_backtrace::<[closure@DefId(1/1:1913 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]::{{closure}}[0]) 0:&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>` at /home/r/src/rust/rustc.2/src/libstd/rt.rs:59:13
= note: inside call to closure at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:310:40
= note: inside call to `std::panicking::try::do_call::<[closure@DefId(1/1:1912 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>` at /home/r/src/rust/rustc.2/src/libstd/panicking.rs:306:5
= note: inside call to `std::panicking::try::<i32, [closure@DefId(1/1:1912 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe]>` at /home/r/src/rust/rustc.2/src/libstd/panic.rs:398:9
= note: inside call to `std::panic::catch_unwind::<[closure@DefId(1/1:1912 ~ std[78f0]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>` at /home/r/src/rust/rustc.2/src/libstd/rt.rs:58:25
= note: inside call to `std::rt::lang_start_internal` at /home/r/src/rust/rustc.2/src/libstd/rt.rs:74:5
= note: inside call to `std::rt::lang_start::<()>`
```
Also notice that we show filenames and line numbers here now.
r? @oli-obk
Clean up some non-mod-rs stuff.
This includes the following:
- Remove unused `non_modrs_mods` from `ParseSess` which as only used for feature gate diagnostics.
- Remove the vestiges of the feature gate tests in `test/ui`, they were only partially removed during stabilization.
- Fix the run-pass test, it was accidentally removed during stabilization.
- Add a ui test to verify error behavior for missing inline-nested mods.
- Add some tests for `#[path]` for inline-nested mods (both mod and non-mod-rs).
- Enable the diagnostic tests on windows, they should be fixed by #49478.
cc @cramertj
reword #[test] attribute error on fn items
fix of [#55787](https://github.com/rust-lang/rust/issues/55787)
Reworded error message from "#[test] attribute is only allowed on fn items" to "#[test] attribute is only allowed on non associated functions"
in which the E0618 "expected function" diagnostic gets a makeover
A woman of wisdom once told me, "Better late than never." (Can't reopen the previously-closed pull request from six months ago [due to GitHub limitations](https://github.com/rust-lang/rust/pull/51098#issuecomment-437647157).)
Now the main span focuses on the erroneous not-a-function callee, while showing the entire call expression is relegated to a secondary span. In the case where the erroneous callee is itself a call, we
point out the definition, and, if the call expression spans multiple lines, tentatively suggest a semicolon (because we suspect that the "outer" call is actually supposed to be a tuple).
The new `bug!` assertion is, in fact, safe (`confirm_builtin_call` is only called by `check_call`, which is only called with a first arg of kind `ExprKind::Call` in `check_expr_kind`).
Resolves#51055.
r? @estebank
