Remove hack for top-level or-patterns in match checking
Follow-up to #66612.
Or-patterns are now truly first-class in match checking. As a side-effect, redundant subpatterns are linted as such, making the `unreachable_patterns` lint a bit more general.
cc #54883
r? @varkor
syntax: Unify macro and attribute arguments in AST
The unified form (`ast::MacArgs`) represents parsed arguments instead of an unstructured token stream that was previously used for attributes.
It also tracks some spans and delimiter kinds better for fn-like macros and macro definitions.
I've been talking about implementing this with @nnethercote in https://github.com/rust-lang/rust/pull/65750#issuecomment-546517322.
The parsed representation is closer to `MetaItem` and requires less token juggling during conversions, so it potentially may be faster.
r? @Centril
Add `enclosing scope` parameter to `rustc_on_unimplemented`
Adds a new parameter to `#[rustc_on_unimplemented]`, `enclosing scope`, which highlights the function or closure scope with a message.
The wip part refers to adding this annotation to `Try` trait to improve ergonomics (which I don't know how to do since I change both std and librustc)
Closes#61709.
Show the sign for signed ops on `exact_div`
r? @RalfJung Cc https://github.com/rust-lang/miri/pull/961/files#r341842128
I'm fairly unhappy with the duplication and the general effort required for this.
Maybe it would be better to add a `display` impl for `ImmTy`?
Layout::pad_to_align is infallible
As per [this comment](https://github.com/rust-lang/rust/issues/55724#issuecomment-441421651) (cc @glandium).
> Per https://github.com/rust-lang/rust/blob/eb981a1/src/libcore/alloc.rs#L63-L65, `layout.size()` is always <= `usize::MAX - (layout.align() - 1)`.
>
> Which means:
>
> * The maximum value `layout.size()` can have is already aligned for `layout.align()` (`layout.align()` being a power of two, `usize::MAX - (layout.align() - 1)` is a multiple of `layout.align()`)
> * Incidentally, any value smaller than that maximum value will align at most to that maximum value.
>
> IOW, `pad_to_align` can not return `Err(LayoutErr)`, except for the layout not respecting its invariants, but we shouldn't care about that.
This PR makes `pad_to_align` return `Layout` directly, representing the fact that it cannot fail.
We want the lifetimes of the patterns contained in the matrix and the
candidate `PatStack` to be the same so that they can be mixed together.
A lot of this would not be necessary if `SmallVec` was covariant in its
type argument (see https://github.com/servo/rust-smallvec/issues/146).
The exact same logic was used in check_arms and check_match to build the
matrix of relevant patterns. It would actually probably have been a bug
if it was not the case, since exhaustiveness checking should be the same
as checking reachability of an additional `_ => ...` match branch.
