improper_ctypes_definitions: allow `Box`
Addresses https://github.com/rust-lang/rust/pull/72700#issuecomment-659449386.
This PR stops linting against `Box` in `extern "C" fn`s for the `improper_ctypes_definitions` lint - boxes are documented to be FFI-safe.
cc @alexcrichton @CryZe
This commit stops linting against `Box` in `extern "C" fn`s for the
`improper_ctypes_definitions` lint - boxes are documented to be
FFI-safe.
Signed-off-by: David Wood <david@davidtw.co>
This commit re-uses the `transparent_newtype_field` function instead of
manually calling `is_zst` on normalized fields to determine which field
in a transparent type is the non-zero-sized field, thus avoiding an ICE.
Signed-off-by: David Wood <david@davidtw.co>
Use for<'tcx> fn pointers in Providers, instead of having Providers<'tcx>.
In order to work around normalization-under-HRTB (for `provide!` in `rustc_metadata`), we ended up with this:
```rust
struct Providers<'tcx> {
type_of: fn(TyCtxt<'tcx>, DefId) -> Ty<'tcx>,
// ...
}
```
But what I initially wanted to do, IIRC, was this:
```rust
struct Providers {
type_of: for<'tcx> fn(TyCtxt<'tcx>, DefId) -> Ty<'tcx>,
// ...
}
```
This PR moves to the latter, for the simple reason that only the latter allows keeping a `Providers` value, or a subset of its `fn` pointer fields, around in a `static` or `thread_local!`, which can be really useful for custom drivers that override queries.
(@jyn514 and I came across a concrete usecase of that in `rustdoc`)
The `provide!` macro in `rustc_metadata` is fixed by making the query key/value types available as type aliases under `ty::query::query_{keys,values}`, not just associated types (this is the first commit).
r? @nikomatsakis
Rename clashing_extern_decl to clashing_extern_declarations.
Rename clashing_extern_decl to clashing_extern_declarations to bring in-line with lint naming conventions.
Fixes#73802.
r? @petrochenkov
improper_ctypes: fix remaining `Reveal:All`
Fixes#60855.
This PR replaces the remaining uses of `ParamEnv::reveal_all` with `LateContext`'s `param_env` (normally `Reveal::UserFacing`) in the improper ctypes lint.
This commit replaces the remaining uses of `ParamEnv::reveal_all` with
`LateContext`'s `param_env` (normally `Reveal::UserFacing`).
Signed-off-by: David Wood <david@davidtw.co>
rustc_lint: only query `typeck_tables_of` when a lint needs it.
This was prompted by @jyn514 running into a situation where `rustdoc` wants to run the `unused_doc` lint without triggering type-checking (as an alternative to the "everybody loops" approach - type-checking may error/ICE because of the `rustdoc` feature of allowing multi-platform docs where the actual bodies of functions may refer to APIs for different platforms).
There was also this comment in the source:
```rust
// FIXME: Make this lazy to avoid running the TypeckTables query?
```
The main effect of this is for lint authors, who now need to use `cx.tables()` to get `&TypeckTables`, as opposed to having them always available in `cx.tables`.
r? @oli-obk or @Manishearth
Implement mixed script confusable lint.
This implements the mixed script confusable lint defined in RFC 2457.
This is blocked on #72069 and https://github.com/unicode-rs/unicode-security/pull/13, and will need a Cargo.toml version bump after those are resolved.
The lint message warning is sub-optimal for now. We'll need a mechanism to properly output `AugmentScriptSet` to screen, this is to be added in `unicode-security` crate.
r? @Manishearth
This commit adjusts the behaviour introduced in a previous commit so
that generic parameters and projections are only allowed in the
definitions mode - and are otherwise a bug. Generic parameters in
declarations are prohibited earlier in the compiler, so if that branch
were reached, it would be a bug.
Signed-off-by: David Wood <david@davidtw.co>
This commit changes the improper ctypes lint (when operating on
definitions) to consider raw pointers or references to sized types as
FFI-safe.
Signed-off-by: David Wood <david@davidtw.co>
This commit adds a new lint - `improper_ctypes_definitions` - which
functions identically to `improper_ctypes`, but on `extern "C" fn`
definitions (as opposed to `improper_ctypes`'s `extern "C" {}`
declarations).
Signed-off-by: David Wood <david@davidtw.co>
Add a lint to catch clashing `extern` fn declarations.
Closes#69390.
Adds lint `clashing_extern_decl` to detect when, within a single crate, an extern function of the same name is declared with different types. Because two symbols of the same name cannot be resolved to two different functions at link time, and one function cannot possibly have two types, a clashing extern declaration is almost certainly a mistake.
This lint does not run between crates because a project may have dependencies which both rely on the same extern function, but declare it in a different (but valid) way. For example, they may both declare an opaque type for one or more of the arguments (which would end up distinct types), or use types that are valid conversions in the language the extern fn is defined in. In these cases, we can't say that the clashing declaration is incorrect.
r? @eddyb
This commit normalizes projections which contain opaque types (opaque types
are otherwise linted against, which is would have previously made the
test cases added in this commit fail).
Signed-off-by: David Wood <david@davidtw.co>
Implement crate-level-only lints checking.
This implements a crate_level_only flag on lints, and when it is true, it becomes an error when user tries to specify this flag upon nodes other than crate node.
This also turns on this flag for all non_ascii_ident lints.
ty: projections in `transparent_newtype_field`
Fixes#73249.
This PR modifies `transparent_newtype_field` so that it handles
projections with generic parameters, where `normalize_erasing_regions`
would ICE.
This commit removes the normalization from `transparent_newtype_field` -
turns out it wasn't necessary and that makes it a bunch simpler -
particularly when handling projections.
Signed-off-by: David Wood <david@davidtw.co>
This commit applies the changes introduced in #72890 to both enum
variants and unions - where the logic prior to #72890 was duplicated.
Signed-off-by: David Wood <david@davidtw.co>
Opaque types cannot be used in extern declarations, and normally cannot
exist in fields - except with type aliases to `impl Trait` and
projections which normalize to them.
Signed-off-by: David Wood <david@davidtw.co>
tag/niche terminology cleanup
The term "discriminant" was used in two ways throughout the compiler:
* every enum variant has a corresponding discriminant, that can be given explicitly with `Variant = N`.
* that discriminant is then encoded in memory to store which variant is active -- but this encoded form of the discriminant was also often called "discriminant", even though it is conceptually quite different (e.g., it can be smaller in size, or even use niche-filling).
After discussion with @eddyb, this renames the second term to "tag". The way the tag is encoded can be either `TagEncoding::Direct` (formerly `DiscriminantKind::Tag`) or `TagEncoding::Niche` (formerly `DiscrimianntKind::Niche`).
This finally resolves some long-standing confusion I had about the handling of variant indices and discriminants, which surfaced in https://github.com/rust-lang/rust/pull/72419.
(There is also a `DiscriminantKind` type in libcore, it remains unaffected. I think this corresponds to the discriminant, not the tag, so that seems all right.)
r? @eddyb
Clean up type alias impl trait implementation
- Removes special case for top-level impl trait
- Removes associated opaque types
- Forbid lifetime elision in let position impl trait. This is consistent with the behavior for inferred types.
- Handle lifetimes in type alias impl trait more uniformly with other parameters
cc #69323
cc #63063Closes#57188Closes#62988Closes#69136Closes#73061
Track span of function in method calls, and use this in #[track_caller]
Fixes#69977
When we parse a chain of method calls like `foo.a().b().c()`, each
`MethodCallExpr` gets assigned a span that starts at the beginning of
the call chain (`foo`). While this is useful for diagnostics, it means
that `Location::caller` will return the same location for every call
in a call chain.
This PR makes us separately record the span of the function name and
arguments for a method call (e.g. `b()` in `foo.a().b().c()`). This
`Span` is passed through HIR lowering and MIR building to
`TerminatorKind::Call`, where it is used in preference to
`Terminator.source_info.span` when determining `Location::caller`.
This new span is also useful for diagnostics where we want to emphasize
a particular method call - for an example, see
https://github.com/rust-lang/rust/pull/72389#discussion_r436035990
Fixes#69977
When we parse a chain of method calls like `foo.a().b().c()`, each
`MethodCallExpr` gets assigned a span that starts at the beginning of
the call chain (`foo`). While this is useful for diagnostics, it means
that `Location::caller` will return the same location for every call
in a call chain.
This PR makes us separately record the span of the function name and
arguments for a method call (e.g. `b()` in `foo.a().b().c()`). This
`Span` is passed through HIR lowering and MIR building to
`TerminatorKind::Call`, where it is used in preference to
`Terminator.source_info.span` when determining `Location::caller`.
This new span is also useful for diagnostics where we want to emphasize
a particular method call - for an example, see
https://github.com/rust-lang/rust/pull/72389#discussion_r436035990
This commit ensures that if a `repr(transparent)` newtype's only
non-zero-sized field is FFI-safe then the newtype is also FFI-safe.
Previously, ZSTs were ignored for the purposes of linting FFI-safety
in transparent structs - thus, only the single non-ZST would be checked
for FFI-safety. However, if the non-zero-sized field is a generic
parameter, and is substituted for a ZST, then the type would be
considered FFI-unsafe (as when every field is thought to be zero-sized,
the type is considered to be "composed only of `PhantomData`" which is
FFI-unsafe).
In this commit, for transparent structs, the non-zero-sized field is
identified (before any substitutions are applied, necessarily) and then
that field's type (now with substitutions) is checked for FFI-safety
(where previously it would have been skipped for being zero-sized in
this case).
To handle the case where the non-zero-sized field is a generic
parameter, which is substituted for `()` (a ZST), and is being used
as a return type - the `FfiUnsafe` result (previously `FfiPhantom`) is
caught and silenced.
Signed-off-by: David Wood <david@davidtw.co>
Manish Goregaokar
bors
David Wood
Ralf Jung
Valentin Lazureanu
Mark Rousskov
Nicholas Nethercote
Tamir Duberstein
Oliver Middleton
Eduard-Mihai Burtescu
Bastian Kauschke
jumbatm
Charles Lew
jumbatm
mark
Dylan DPC
Matthew Jasper
Aaron Hill
Lzu Tao