This is a large spring-cleaning commit now that the 0.12.0 release has passed removing an amount of deprecated functionality. This removes a number of deprecated crates (all still available as cargo packages in the rust-lang organization) as well as a slew of deprecated functions. All `#[crate_id]` support has also been removed.
I tried to avoid anything that was recently deprecated, but I may have missed something! The major pain points of this commit is the fact that rustc/syntax have `#[allow(deprecated)]`, but I've removed that annotation so moving forward they should be cleaned up as we go.
Spring cleaning is here! In the Fall! This commit removes quite a large amount
of deprecated functionality from the standard libraries. I tried to ensure that
only old deprecated functionality was removed.
This is removing lots and lots of deprecated features, so this is a breaking
change. Please consult the deprecation messages of the deleted code to see how
to migrate code forward if it still needs migration.
[breaking-change]
Check object lifetime bounds in coercions, not just trait bounds. Fixes#18055.
r? @pcwalton
This is a [breaking change]. Change code like this:
fn foo(v: &[u8]) -> Box<Clone+'static> { ... }
to make the lifetimes agree:
// either...
fn foo(v: &'static[u8]) -> Box<Clone+'static> { box v }
// or ...
fn foo<'a>(v: &'a [u8]) -> Box<Clone+'a> { box v }
The representability-checking routine ```is_type_representable``` failed to detect structural recursion in some cases, leading to stack overflow later on.
The first problem was in the loop in the ```find_nonrepresentable``` function. We were improperly terminating the iteration if we saw a ```ContainsRecursive``` condition. We should have kept going in case a later member of the struct (or enum, etc) being examined was ```SelfRecursive```. The example from #17431 triggered this issue:
```rust
use std::sync::Mutex;
struct Foo { foo: Mutex<Option<Foo>> }
impl Foo { fn bar(self) {} }
fn main() {}
```
I'm not 100% sure, but I think the ```ty_enum``` case of ```fn type_structurally_recursive``` had a similar problem, since it could ```break``` on ```ContainsRecursive``` before looking at all variants. I've replaced this with a ```flat_map``` call.
The second problem was that we were failing to identify code like ```struct Foo { foo: Option<Option<Foo>> }``` as SelfRecursive, even though we correctly identified ```struct Foo { foo: Option<Foo> }```. This was caused by using DefId's for the ```ContainsRecursive``` check, which meant the nested ```Option```s were identified as illegally recursive (because ```ContainsRecursive``` is not an error, we would then keep compiling and eventually hit a stack overflow).
In order to make sure that we can recurse through the different ```Option``` invocations, I've changed the type of ```seen``` from ```Vec<DefId>``` to ```Vec<t>``` and added a separate ```same_type``` function to check whether two types are the same when generics are taken into account. Now we only return ```ContainsRecursive``` when this stricter check is satisfied. (There's probably a better way to do this, and I'm not sure my code is entirely correct--but my knowledge of rustc internals is pretty limited, so any help here would be appreciated!)
Note that the ```SelfRecursive``` check is still comparing ```DefId```s--this is necessary to prevent code like this from being allowed:
```rust
struct Foo { x: Bar<Foo> }
struct Bar<T> { x: Bar<Foo> }
```
All four of the new ```issue-17431``` tests cause infinite recursion on master, and errors with this pull request. I wrote the extra ```issue-3008-4.rs``` test to make sure I wasn't introducing a regression.
Fixes#17431.
This adds ‘help’ diagnostic messages to rustc. This is used for anything that provides help to the user, particularly the `--explain` messages that were previously integrated into the relevant error message.
They look like this:
```
match.rs:10:13: 10:14 error: unreachable pattern [E0001]
match.rs:10 1 => {},
^
match.rs:3:1: 3:38 note: in expansion of foo!
match.rs:7:5: 20:2 note: expansion site
match.rs:10:13: 10:14 help: pass `--explain E0001` to see a detailed explanation
```
(`help` is coloured cyan.) Adding these errors on a separate line stops the lines from being too long, as discussed in #16619.
detected (correctly) that there was only one impl and hence ignored the
`Self` bound completely. I (semi-arbitrarily) elected to delect the
impl, forcing the trait matcher to be more conservative and lean on the
where clauses in scope, yielding the original error message.
On 32-bit architectures, the size calculations on two of the tests wrap-around
in typeck, which gives the relevant arrays a size of 0, which is (correctly)
successfully allocated.
