RFC 2008: Future-proofing enums/structs with #[non_exhaustive] attribute
This work-in-progress pull request contains my changes to implement [RFC 2008](https://github.com/rust-lang/rfcs/pull/2008). The related tracking issue is #44109.
As of writing, enum-related functionality is not included and there are some issues related to tuple/unit structs. Enum related tests are currently ignored.
WIP PR requested by @nikomatsakis [in Gitter](https://gitter.im/rust-impl-period/WG-compiler-middle?at=59e90e6297cedeb0482ade3e).
DefaultImpl is a highly confusing name for what we now call auto impls,
as in `impl Send for ..`. The name auto impl is not formally decided
but for sanity anything is better than `DefaultImpl` which refers
neither to `default impl` nor to `impl Default`.
incr.comp.: Implement compiler diagnostic persistence.
This PR implements storing and loading diagnostics that the compiler generates and thus allows for emitting warnings during incremental compilation without actually re-evaluating the thing the warning originally came from. It also lays some groundwork for storing and loading type information and MIR in the incr. comp. cache.
~~It is still work in progress:~~
- ~~There's still some documentation to be added.~~
- ~~The way anonymous queries are handled might lead to duplicated emissions of warnings. Not sure if there is a better way or how frequent such duplication would be in practice.~~
Diagnostic message duplication is addressed separately in #45519.
r? @nikomatsakis
- Don't hash traits in scope as part of HIR hashing any more.
- Some queries returned DefIndexes from other crates.
- Provide a generic way of stably hashing maps (not used everywhere yet).
This is a big map that ends up inside of a `CrateContext` during translation for
all codegen units. This means that any change to the map may end up causing an
incremental recompilation of a codegen unit! In order to reduce the amount of
dependencies here between codegen units and the actual input crate this commit
refactors dealing with exported symbols and such into various queries.
The new queries are largely based on existing queries with filled out
implementations for the local crate in addition to external crates, but the main
idea is that while translating codegen untis no unit needs the entire set of
exported symbols, instead they only need queries about particulare `DefId`
instances every now and then.
The linking stage, however, still generates a full list of all exported symbols
from all crates, but that's going to always happen unconditionally anyway, so no
news there!
This commit moves the definition of the `ExportedSymbols` structure to the
`rustc` crate and then creates a query that'll be used to construct the
`ExportedSymbols` set. This in turn uses the reachablity query exposed in the
previous commit.
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)
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.
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
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
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.
This commit moves the `crates` method to a query and then migrates all callers
to use a query instead of the now-renamed `crates_untracked` method where
possible.
Closes#41417
Previously a `Symbol` was stored there, but this ended up causing hash
collisions in situations that otherwise shouldn't have a hash collision. Only
the symbol's string value was hashed, but it was possible for distinct symbols
to have the same string value, fooling various calcuations into thinking that
these paths *didn't* need disambiguating data when in fact they did!
By storing `InternedString` instead we're hopefully triggering all the exising
logic to disambiguate paths with same-name `Symbol` but actually distinct
locations.
This commit primarily removes the `stability` field from `TyCtxt` as well as its
internal mutable state, instead using a query to build the stability index as
well as primarily using queries for other related lookups.
Like previous commits the calculation of the stability index is wrapped in a
`with_ignore` node to avoid regressing the current tests, and otherwise this
commit also introduces #44232 but somewhat intentionally so.
Should hopefully more accurately reflect what's happening! This commit also
removes the cache in the cstore implementation as it's already cached through
the query infrastructure.
These are only called pre-TyCtxt (e.g. lowering/resolve), so make it explicit in
the name that they're untracked and therefore unsuitable to called elsewhere.
This commit moves the calculation of the `LanguageItems` structure into a
query rather than being calculated before the `TyCtxt` exists, with the eventual
end goal of removing some `CrateStore` methods.
The main use of `CrateStore` *before* the `TyCtxt` is created is during
resolution, but we want to be sure that any methods used before resolution are
not used after the `TyCtxt` is created. This commit starts moving the methods
used by resolve to all be named `{name}_untracked` where the rest of the
compiler uses just `{name}` as a query.
During this transition a number of new queries were added to account for
post-resolve usage of these methods.
This commit started by moving methods from `CrateStore` to queries, but it ended
up necessitating some deeper refactorings to move more items in general to
queries.
Before this commit the *resolver* would walk over the AST and process foreign
modules (`extern { .. }` blocks) and collect `#[link]` annotations. It would
then also process the command line `-l` directives and such. This information
was then stored as precalculated lists in the `CrateStore` object for iterating
over later.
After this, commit, however, this pass no longer happens during resolution but
now instead happens through queries. A query for the linked libraries of a crate
will crawl the crate for `extern` blocks and then process the linkage
annotations at that time.
