`panic!` does not print any identifying information for threads that are
unnamed. However, in many cases, the thread ID can be determined.
This changes the panic message from something like this:
thread '<unnamed>' panicked at src/main.rs:3:5:
explicit panic
To something like this:
thread '<unnamed>' (0xff9bf) panicked at src/main.rs:3:5:
explicit panic
Stack overflow messages are updated as well.
This change applies to both named and unnamed threads. The ID printed is
the OS integer thread ID rather than the Rust thread ID, which should
also be what debuggers print.
```
error[E0610]: `{integer}` is a primitive type and therefore doesn't have fields
--> $DIR/attempted-access-non-fatal.rs:7:15
|
LL | let _ = 2.l;
| ^
|
help: if intended to be a floating point literal, consider adding a `0` after the period and a `f64` suffix
|
LL - let _ = 2.l;
LL + let _ = 2.0f64;
|
```
```
error[E0432]: unresolved import `some_novel_crate`
--> file.rs:1:5
|
1 | use some_novel_crate::Type;
| ^^^^^^^^^^^^^^^^ use of unresolved module or unlinked crate `some_novel_crate`
```
On resolve errors where there might be a missing crate, mention `cargo add foo`:
```
error[E0433]: failed to resolve: use of unresolved module or unlinked crate `nope`
--> $DIR/conflicting-impl-with-err.rs:4:11
|
LL | impl From<nope::Thing> for Error {
| ^^^^ use of unresolved module or unlinked crate `nope`
|
= help: if you wanted to use a crate named `nope`, use `cargo add nope` to add it to your `Cargo.toml`
```
When both `std::` and `core::` items are available, only suggest the
`std::` ones. We ensure that in `no_std` crates we suggest `core::`
items.
Ensure that the list of items suggested to be imported are always in the
order of local crate items, `std`/`core` items and finally foreign crate
items.
Tweak wording of import suggestion: if there are multiple items but they
are all of the same kind, we use the kind name and not the generic "items".
Fix#83564.
Do not provide a structured suggestion when the arguments don't match.
```
error[E0599]: no method named `test_mut` found for struct `Vec<{integer}>` in the current scope
--> $DIR/auto-ref-slice-plus-ref.rs:7:7
|
LL | a.test_mut();
| ^^^^^^^^
|
= help: items from traits can only be used if the trait is implemented and in scope
note: `MyIter` defines an item `test_mut`, perhaps you need to implement it
--> $DIR/auto-ref-slice-plus-ref.rs:14:1
|
LL | trait MyIter {
| ^^^^^^^^^^^^
help: there is a method `get_mut` with a similar name, but with different arguments
--> $SRC_DIR/core/src/slice/mod.rs:LL:COL
```
Consider methods beyond inherent ones when suggesting typos.
```
error[E0599]: no method named `owned` found for reference `&dyn Foo` in the current scope
--> $DIR/object-pointer-types.rs:11:7
|
LL | fn owned(self: Box<Self>);
| --------- the method might not be found because of this arbitrary self type
...
LL | x.owned();
| ^^^^^ help: there is a method with a similar name: `to_owned`
```
Fix#101013.
add more niches to rawvec
Previously RawVec only had a single niche in its `NonNull` pointer. With this change it now has `isize::MAX` niches since half the value-space of the capacity field is never needed, we can't have a capacity larger than isize::MAX.
Stabilize `type_name_of_val`
Make the following API stable:
```rust
// in core::any
pub fn type_name_of_val<T: ?Sized>(_val: &T) -> &'static str
```
This is a convenience method to get the type name of a value, as opposed to `type_name` that takes a type as a generic.
Const stability is not added because this relies on `type_name` which is also not const. That has a blocking issue https://github.com/rust-lang/rust/issues/97156.
Wording was also changed to direct most of the details to `type_name` so we don't have as much duplicated documentation.
Fixes tracking issue #66359.
There were two main concerns in the tracking issue:
1. Naming: `type_name_of` and `type_name_of_val` seem like the only mentioned options. Differences in opinion here come from `std::mem::{size_of, align_of, size_of_val, align_of_val}`. This PR leaves the name as `type_name_of_val`, but I can change if desired since it is pretty verbose.
2. What this displays for `&dyn`: I don't think that having `type_name_of_val` function resolve those is worth the headache it would be, see https://github.com/rust-lang/rust/issues/66359#issuecomment-1718480774 for some workarounds. I also amended the docs wording to leave it open-ended, in case we have means to change that behavior in the future.
``@rustbot`` label -T-libs +T-libs-api +needs-fcp
r? libs-api
`tokenstream::Spacing` appears on all `TokenTree::Token` instances,
both punct and non-punct. Its current usage:
- `Joint` means "can join with the next token *and* that token is a
punct".
- `Alone` means "cannot join with the next token *or* can join with the
next token but that token is not a punct".
The fact that `Alone` is used for two different cases is awkward.
This commit augments `tokenstream::Spacing` with a new variant
`JointHidden`, resulting in:
- `Joint` means "can join with the next token *and* that token is a
punct".
- `JointHidden` means "can join with the next token *and* that token is a
not a punct".
- `Alone` means "cannot join with the next token".
This *drastically* improves the output of `print_tts`. For example,
this:
```
stringify!(let a: Vec<u32> = vec![];)
```
currently produces this string:
```
let a : Vec < u32 > = vec! [] ;
```
With this PR, it now produces this string:
```
let a: Vec<u32> = vec![] ;
```
(The space after the `]` is because `TokenTree::Delimited` currently
doesn't have spacing information. The subsequent commit fixes this.)
The new `print_tts` doesn't replicate original code perfectly. E.g.
multiple space characters will be condensed into a single space
character. But it's much improved.
`print_tts` still produces the old, uglier output for code produced by
proc macros. Because we have to translate the generated code from
`proc_macro::Spacing` to the more expressive `token::Spacing`, which
results in too much `proc_macro::Along` usage and no
`proc_macro::JointHidden` usage. So `space_between` still exists and
is used by `print_tts` in conjunction with the `Spacing` field.
This change will also help with the removal of `Token::Interpolated`.
Currently interpolated tokens are pretty-printed nicely via AST pretty
printing. `Token::Interpolated` removal will mean they get printed with
`print_tts`. Without this change, that would result in much uglier
output for code produced by decl macro expansions. With this change, AST
pretty printing and `print_tts` produce similar results.
The commit also tweaks the comments on `proc_macro::Spacing`. In
particular, it refers to "compound tokens" rather than "multi-char
operators" because lifetimes aren't operators.
Make the following API stable:
// in core::any
pub fn type_name_of_val<T: ?Sized>(_val: &T) -> &'static str
Const stability is not added because this relies on `type_name` which is also
not const. That has a blocking issue.
Fixes#66359
Eliminate ZST allocations in `Box` and `Vec`
This PR fixes 2 issues with `Box` and `RawVec` related to ZST allocations. Specifically, the `Allocator` trait requires that:
- If you allocate a zero-sized layout then you must later deallocate it, otherwise the allocator may leak memory.
- You cannot pass a ZST pointer to the allocator that you haven't previously allocated.
These restrictions exist because an allocator implementation is allowed to allocate non-zero amounts of memory for a zero-sized allocation. For example, `malloc` in libc does this.
Currently, ZSTs are handled differently in `Box` and `Vec`:
- `Vec` never allocates when `T` is a ZST or if the vector capacity is 0.
- `Box` just blindly passes everything on to the allocator, including ZSTs.
This causes problems due to the free conversions between `Box<[T]>` and `Vec<T>`, specifically that ZST allocations could get leaked or a dangling pointer could be passed to `deallocate`.
This PR fixes this by changing `Box` to not allocate for zero-sized values and slices. It also fixes a bug in `RawVec::shrink` where shrinking to a size of zero did not actually free the backing memory.
