This first patch starts by moving around pieces of state related to
type checking. The goal is to slowly unify the type checking state
into a single typing context. This initial patch moves the
ParameterEnvironment into the InferCtxt and moves shared tables
from Inherited and ty::ctxt into their own struct Tables. This
is the foundational work to refactoring the type checker to
enable future evolution of the language and tooling.
The stability check checks the `PublicItems` map when giving errors if
there is a #[stable] item with a public contents that doesn't not have
its own stability. Without recording this, struct fields and enum
variants will not get errors for e.g. stable modules with unmarked
functions internally.
This is just improving the compiler's precision to give the standard
library developers more information earlier.
E.g.
#![staged_api]
#![feature(staged_api)]
#![crate_type = "lib"]
#[stable(feature = "rust1", since = "1.0.0")]
pub struct Foo {
pub x: i32
}
#[stable(feature = "rust1", since = "1.0.0")]
pub mod bar {
pub fn baz() {}
}
Without the patch it gives:
test.rs:12:5: 12:20 error: This node does not have a stability attribute
test.rs:12 pub fn baz() {}
^~~~~~~~~~~~~~~
error: aborting due to previous error
With the patch it gives:
test.rs:7:9: 7:15 error: This node does not have a stability attribute
test.rs:7 pub x: i32
^~~~~~
test.rs:12:5: 12:20 error: This node does not have a stability attribute
test.rs:12 pub fn baz() {}
^~~~~~~~~~~~~~~
error: aborting due to 2 previous errors
This is one more step towards completing #13231
This series of commits add support for default trait implementations. The changes in this PR don't break existing code and they are expected to preserve the existing behavior in the compiler as far as built-in bounds checks go.
The PR adds negative implementations of `Send`/`Sync` for some types and it removes the special cases for `Send`/`Sync` during the trait obligations checks. That is, it now fully relies on the traits check rather than lang items.
Once this patch lands and a new snapshot is created, it'll be possible to add default impls for `Send` and `Sync` and remove entirely the use of `BuiltinBound::{BoundSend,BoundSync}` for positive implementations as well.
This PR also removes the restriction on negative implementations. That is, it is now possible to add negative implementations for traits other than `Send`/`Sync`
