(The idea is that the StorageDead marks the point where the memory can
be deallocated, and the EndRegion is marking where borrows of that
memory can no longer legally exist.)
Fix mispositioned error indicators
Fixes#38384
Most of the Rust community uses 4 spaces for indentation,
but there are also tab users of Rust (including myself!).
This patch fixes a bug in error printing which mispositions
error indicators when near code with tabs.
The code attempted to fix the issue by replacing spaces
with tabs, but it sadly wasn't enough, as sometimes
you may not print spaces but _ or ^ instead.
This patch employs the reverse strategy: it replaces each
tab with a space, so that the number of _ and ^ and spaces
in error indicators below the code snippet line up
perfectly.
In a study [1] preceeding this patch, we could see that
this strategy is also chosen by gcc version 6.3.0.
Its not perfect, as the output is not beautiful, but its
the easiest to implement. If anyone wants to improve on
this, be my guest! This patch is meant as improvement of
the status quo, not as perfect end status. It fixes the
actual issue of mispositioning error indicators.
[1]: https://github.com/rust-lang/rust/issues/38384#issuecomment-326813710
rustc: Make `CrateStore` private to `TyCtxt`
This commit makes the `CrateStore` object private to the `ty/context.rs` module and also absent on the `Session` itself.
cc #44390
cc #44341 (initial commit pulled and rebased from here)
impl Hasher for {&mut Hasher, Box<Hasher>}
**Rationale:** The `Hash` trait has `fn hash<H: Hasher>(&self, state: &mut H)`, which can only accept a `Sized` hasher, even if the `Hasher` trait is object-safe. We cannot retroactively add the `?Sized` bound without breaking stability, thus implementing `Hasher` to a trait object reference is the next best solution.
**Warning:** These `impl` are insta-stable, and should need an FCP. I don't think a full RFC is necessary.
Autodetect the type of allocator crate used
Annotate the allocator crates (allocator_system, allocator_jemalloc) by the type of allocator they are. If one is requested as an exe allocator, detect its type by the flags.
This has the effect that using this (de jure wrong) configuration in the target spec works instead of producing a really unhelpful and arcane linker error:
"exe-allocation-crate": "alloc_system"
Fixes#43524.
There are two yet unsolved FIXME's, I'll be glad for some advice on what to do with them.
Add or_default to Entry APIs
As argued for in #44324, this PR adds a new `or_default` method to the various `Entry` APIs (currently just for `BTreeMap` and `HashMap`) when `V: Default`. This method is effectively a shorthand for `or_insert_with(Default::default)`.
Additional traits for std::mem::ManuallyDrop
The first commit adds `Clone` and `Copy` trait implementations for `ManuallyDrop`. Although `Drop` and `Copy` cannot be used together, this may be useful for generics.
The second commit adds implementations common traits. I do not think this is necessary, as they could be implemented in a wrapper type outside the standard library, but it would make `ManuallyDrop` more convenient to use.
Evaluate fixed-length array length expressions lazily.
This is in preparation for polymorphic array lengths (aka `[T; T::A]`) and const generics.
We need deferred const-evaluation to break cycles when array types show up in positions which require knowing the array type to typeck the array length, e.g. the array type is in a `where` clause.
The final step - actually passing bounds in scope to array length expressions from the parent - is not done because it still produces cycles when *normalizing* `ParamEnv`s, and @nikomatsakis' in-progress lazy normalization work is needed to deal with that uniformly.
However, the changes here are still useful to unlock work on const generics, which @EpicatSupercell manifested interest in, and I might be mentoring them for that, but we need this baseline first.
r? @nikomatsakis cc @oli-obk
rustbuild: Fix a distribution bug with rustdoc
Apparently `File::create` was called when there was an existing hard link or the
like, causing an existing file to get accidentally truncated!
Closes#44487
Fix regression in promotion of rvalues referencing a static
This commit makes librustc_passes::consts::CheckCrateVisitor properly
mark expressions as promotable if they reference a static, as it's
perfectly fine for one static to reference another. It fixes a
regression that prevented a temporary rvalue from referencing a static
if it was itself declared within a static.
Prior to commit https://github.com/rust-lang/rust/commit/b8c05fe90bc,
`region::ScopeTree` would only register a 'terminating scope' for function
bodies. Thus, while rvalues in a static that referenced a static would be marked
unpromotable, the lack of enclosing scope would cause
mem_categorization::MemCategorizationContext::cat_rvalue_node
to compute a 'temporary scope' of `ReStatic`. Since this had the same
effect as explicitly selecting a scope of `ReStatic`
due to the rvalue being marked by CheckCrateVisitor as promotable,
no issue occurred.
However, commit https://github.com/rust-lang/rust/commit/b8c05fe90bc
made ScopeTree unconditionally register a 'terminating scope'
Since mem_categorization would now compute a non-static 'temporary scope', the
aforementioned rvalues would be erroneously marked as living for too
short a time.
By fixing the behavior of CheckCrateVisitor, this commit avoids changing
mem_categorization's behavior, while ensuring that temporary values in
statics are still allowed to reference other statics.
Fixes issue #44373
Apparently `File::create` was called when there was an existing hard link or the
like, causing an existing file to get accidentally truncated!
Closes#44487
This'll allow us to reconstruct query parameters purely from the `DepNode`
they're associated with. Some queries could move straight to `HirId` but others
that don't always have a correspondance between `HirId` and `DefId` moved to
two-level maps where the query operates over a `DefIndex`, returning a map,
which is then keyed off `ItemLocalId`.
Closes#44414
