projection sensitive to "mode" (most importantly, trans vs middle).
This commit introduces several pieces of iteration infrastructure in the
specialization graph data structure, as well as various helpers for
finding the definition of a given item, given its kind and name.
In addition, associated type projection is now *mode-sensitive*, with
three possible modes:
- **Topmost**. This means that projection is only possible if there is a
non-`default` definition of the associated type directly on the
selected impl. This mode is a bit of a hack: it's used during early
coherence checking before we have built the specialization
graph (and therefore before we can walk up the specialization
parents to find other definitions). Eventually, this should be
replaced with a less "staged" construction of the specialization
graph.
- **AnyFinal**. Projection succeeds for any non-`default` associated
type definition, even if it is defined by a parent impl. Used
throughout typechecking.
- **Any**. Projection always succeeds. Used by trans.
The lasting distinction here is between `AnyFinal` and `Any` -- we wish
to treat `default` associated types opaquely for typechecking purposes.
In addition to the above, the commit includes a few other minor review fixes.
typestrong const integers
~~It would be great if someone could run crater on this PR, as this has a high danger of breaking valid code~~ Crater ran. Good to go.
----
So this PR does a few things:
1. ~~const eval array values when const evaluating an array expression~~
2. ~~const eval repeat value when const evaluating a repeat expression~~
3. ~~const eval all struct and tuple fields when evaluating a struct/tuple expression~~
4. remove the `ConstVal::Int` and `ConstVal::Uint` variants and replace them with a single enum (`ConstInt`) which has variants for all integral types
* `usize`/`isize` are also enums with variants for 32 and 64 bit. At creation and various usage steps there are assertions in place checking if the target bitwidth matches with the chosen enum variant
5. enum discriminants (`ty::Disr`) are now `ConstInt`
6. trans has its own `Disr` type now (newtype around `u64`)
This obviously can't be done without breaking changes (the ones that are noticable in stable)
We could probably write lints that find those situations and error on it for a cycle or two. But then again, those situations are rare and really bugs imo anyway:
```rust
let v10 = 10 as i8;
let v4 = 4 as isize;
assert_eq!(v10 << v4 as usize, 160 as i8);
```
stops compiling because 160 is not a valid i8
```rust
struct S<T, S> {
a: T,
b: u8,
c: S
}
let s = S { a: 0xff_ff_ff_ffu32, b: 1, c: 0xaa_aa_aa_aa as i32 };
```
stops compiling because `0xaa_aa_aa_aa` is not a valid i32
----
cc @eddyb @pnkfelix
related: https://github.com/rust-lang/rfcs/issues/1071
Do not report errors from regionck if other errors were already reported
Do not report errors from regionck if other errors were already reported during the lifetime of this inferencer. Fixes#30580.
r? @arielb1
Add Pass manager for MIR
A new PR, since rebasing the original one (https://github.com/rust-lang/rust/pull/31448) properly was a pain. Since then there has been several changes most notable of which:
1. Removed the pretty-printing with `#[rustc_mir(graphviz/pretty)]`, mostly because we now have `--unpretty=mir`, IMHO that’s the direction we should expand this functionality into;
2. Reverted the infercx change done for typeck, because typeck can make an infercx for itself by being a `MirMapPass`
r? @nikomatsakis
Fix name resolution in lexical scopes
Currently, `resolve_item_in_lexical_scope` does not check the "ribs" (type parameters and local variables). This can allow items that should be shadowed by type parameters to be named.
For example,
```rust
struct T { i: i32 }
fn f<T>() {
let t = T { i: 0 }; // This use of `T` resolves to the struct, not the type parameter
}
mod Foo {
pub fn f() {}
}
fn g<Foo>() {
Foo::f(); // This use of `Foo` resolves to the module, not the type parameter
}
```
This PR changes `resolve_item_in_lexical_scope` so that it fails when the item is shadowed by a rib (fixes#32120).
This is a [breaking-change], but it looks unlikely to cause breakage in practice.
r? @nikomatsakis
std: Fix tracking issues and clean deprecated APIs
This PR fixes up a number of discrepancies found with tracking issues (some closed, some needed new ones, etc), and also cleans out all pre-1.8 deprecated APIs. The big beast here was dealing with `std::dynamic_lib`, and via many applications of a large hammer it's now out of the standard library.
Removes all unstable and deprecated APIs prior to the 1.8 release. All APIs that
are deprecated in the 1.8 release are sticking around for the rest of this
cycle.
Some notable changes are:
* The `dynamic_lib` module was moved into `rustc_back` as the compiler still
relies on a few bits and pieces.
* The `DebugTuple` formatter now special-cases an empty struct name with only
one field to append a trailing comma.
Forbid items with the same name from appearing in overlapping inherent impl blocks
For example, the following is now correctly illegal:
```rust
struct Foo;
impl Foo {
fn id() {}
}
impl Foo {
fn id() {}
}
```
"Overlapping" here is determined the same way it is for traits (and in fact shares the same code path): roughly, there must be some way of substituting any generic types to unify the impls, such that none of the `where` clauses are provably unsatisfiable under such a unification.
Along the way, this PR also introduces an `ImplHeader` abstraction (the first commit) that makes it easier to work with impls abstractly (without caring whether they are trait or inherent impl blocks); see the first commit.
Closes#22889
r? @nikomatsakis
lint: mark associated types as live for the dead_code pass
Associated types of trait impls were being excluded from the live list. So types that only appeared in trait impls were being marked as dead code.
Forbid glob-importing from a type alias
This PR forbids glob-importing from a type alias or trait (fixes#30560):
```rust
type Alias = ();
use Alias::*; // This is currently allowed but shouldn't be
```
This is a [breaking-change]. Since the disallowed glob imports don't actually import anything, any breakage can be fixed by removing the offending glob import.
r? @alexcrichton
`assert_eq!(-9223372036854775808isize as u64, 0x8000000000000000);`
fails on 32 bit and succeeds on 64 bit. These commits don't change that behavior.
The following worked before my changes, because the discriminant was
always processed as `u64`.
Now it fails, because the discriminant of `Bu64` is now `0` instead of `-9223372036854775808`. This is more in line with the above assertion's code, since
`-9223372036854775808isize as u64` on 32 bit yielded `0`.
```rust
enum Eu64 {
Au64 = 0,
Bu64 = 0x8000_0000_0000_0000
}
```
Prefer 'associated function' over 'static method' in msg.
TRPL seems to refer to 'static functions' as 'associated functions'.
This terminology should be used consistently.
Fix a regression in import resolution
This fixes#32089 (caused by #31726) by deducing that name resolution has failed (as opposed to being determinate) in more cases.
r? @nikomatsakis
Distinguish fn item types to allow reification from nothing to fn pointers.
The first commit is a rebase of #26284, except for files that have moved since.
This is a [breaking-change], due to:
* each FFI function has a distinct type, like all other functions currently do
* all generic parameters on functions are recorded in their item types, e.g.:
`size_of::<u8>` & `size_of::<i8>`'s types differ despite their identical signature.
* function items are zero-sized, which will stop transmutes from working on them
The first two cases are handled in most cases with the new coerce-unify logic,
which will combine incompatible function item types into function pointers,
at the outer-most level of if-else chains, match arms and array literals.
The last case is specially handled during type-checking such that transmutes
from a function item type to a pointer or integer type will continue to work for
another release cycle, but are being linted against. To get rid of warnings and
ensure your code will continue to compile, cast to a pointer before transmuting.
