This commit shards the all-encompassing `core`, `std_misc`, `collections`, and `alloc` features into finer-grained components that are much more easily opted into and tracked. This reflects the effort to push forward current unstable APIs to either stabilization or removal. Keeping track of unstable features on a much more fine-grained basis will enable the library subteam to quickly analyze a feature and help prioritize internally about what APIs should be stabilized.
A few assorted APIs were deprecated along the way, but otherwise this change is just changing the feature name associated with each API. Soon we will have a dashboard for keeping track of all the unstable APIs in the standard library, and I'll also start making issues for each unstable API after performing a first-pass for stabilization.
Currently in the E0252 message, traits and modules are all called types (as in "a type named `Foo` has already been imported", even when `Foo` was a trait or module). This commit changes that to additionally detect when the import in question is a trait or module and report it accordingly.
Fixes#25396.
Previously, it said "import `Foo` conflicts with existing submodule" even
when it was a type alias, enum, or trait. The message now says the conflict
is with "type in this module" in the case of the first two, and "trait in
this module" for the last one.
Fixes#24081.
Unlike coercing from reference to unsafe pointer, coercing between two
unsafe pointers doesn't need an AutoDerefRef, because there is no region
that regionck would need to know about.
In unoptimized libcore, this reduces the number of "auto_deref" allocas
from 174 to 4.
Currently in the E0252 message, traits and modules are all called types
(as in "a type named `Foo` has already been imported", even when `Foo` was
a trait or module). This commit changes that to additionally detect when
the import in question is a trait or module and report it accordingly.
Fixes#25396.
When we successfully resolve a trait reference with no type/lifetime parameters, like `i32: Foo` or `Box<u32>: Sized`, this is in fact globally true. This patch adds a simple global to the tcx to cache such cases. The main advantage of this is really about caching things like `Box<Vec<Foo>>: Sized`. It also points to the need to revamp our caching infrastructure -- the current caches make selection cost cheaper, but we still wind up paying a high cost in the confirmation process, and in particular unrolling out dependent obligations. Moreover, we should probably do caching more uniformly and with a key that takes the where-clauses into account. But that's for later.
For me, this shows up as a reasonably nice win (20%) on Servo's script crate (when built in dev mode). This is not as big as my initial measurements suggested, I think because I was building my rustc with more debugging enabled at the time. I've not yet done follow-up profiling and so forth to see where the new hot spots are. Bootstrap times seem to be largely unaffected.
cc @pcwalton
This is technically a [breaking-change] in that functions with unsatisfiable where-clauses may now yield errors where before they may have been accepted. Even before, these functions could never have been *called* by actual code. In the future, such functions will probably become illegal altogether, but in this commit they are still accepted, so long as they do not rely on the unsatisfiable where-clauses. As before, the functions still cannot be called in any case.
Previously, it said "import `Foo` conflicts with existing submodule" even
when it was a type alias, enum, or trait. The message now says the conflict
is with "type in this module" in the case of the first two, and "trait in
this module" for the last one.
Fixes#24081.
Unlike coercing from reference to unsafe pointer, coercing between two
unsafe pointers doesn't need an AutoDerefRef, because there is no region
that regionck would need to know about.
In unoptimized libcore, this reduces the number of "auto_deref" allocas
from 174 to 4.
again, do it once and then just remember the expanded form. At the same
time, filter globally nameable predicates out of the environment, since
they can cause cache errors (and they are not necessary in any case).
Two commits here: one which removes a bunch of tests, and re-enables a few that work.
Second updates the syntax of one of the failing tests. It still doesn't pass, but at least it compiles.
Most of these are old, but some specific messages for specific tests:
* trait-contravariant-self.rs: failed due to a soundess hole:
05e3248a79
* process-detatch: 15966c3c1f
says "this test is being ignored until signals are implemented" That's
not happening for a long time, and when it is, we'll write tests for
it.
* deep-vector{,2}.rs: "too big for our poor macro infrastructure", and has
been ignored over a year.
* borrowck-nested-calls.rs's FIXME #6268 was closed in favor of
rust-lang/rfcs#811
* issue-15167.rs works properly now
* issue-9737.rs works properly now
* match-var-hygiene.rs works properly now
Addresses a chunk of #3965
Part of #24407.
Currently the diagnostics for range patterns are a bit wrong:
```rust
fn main() {
match 5u32 {
0 ... 10 => (),
'a' ... 10 => (),
10 ... 'z' => (),
"what" ... 10 => (),
"what" ... "well" => (),
10 ... "what" => ()
}
}
```
```
range.rs:4:9: 4:19 error: mismatched types in range:
expected integral variable,
found char [E0211]
range.rs:4 'a' ... 10 => (),
^~~~~~~~~~
range.rs:4:9: 4:16 error: only char and numeric types are allowed in range [E0029]
range.rs:4 'a' ... 10 => (),
^~~~~~~
range.rs:4:9: 4:19 error: mismatched types:
expected `u32`,
found `char`
(expected u32,
found char) [E0308]
range.rs:4 'a' ... 10 => (),
^~~~~~~~~~
range.rs:5:9: 5:19 error: mismatched types in range:
expected char,
found integral variable [E0211]
range.rs:5 10 ... 'z' => (),
^~~~~~~~~~
range.rs:5:9: 5:15 error: only char and numeric types are allowed in range [E0029]
range.rs:5 10 ... 'z' => (),
^~~~~~
range.rs:6:9: 6:22 error: mismatched types in range:
expected integral variable,
found &-ptr [E0211]
range.rs:6 "what" ... 10 => (),
^~~~~~~~~~~~~
range.rs:6:9: 6:19 error: only char and numeric types are allowed in range [E0029]
range.rs:6 "what" ... 10 => (),
^~~~~~~~~~
range.rs:6:9: 6:22 error: mismatched types:
expected `u32`,
found `&'static str`
(expected u32,
found &-ptr) [E0308]
range.rs:6 "what" ... 10 => (),
^~~~~~~~~~~~~
range.rs:7:9: 7:19 error: only char and numeric types are allowed in range [E0029]
range.rs:7 "what" ... "well" => (),
^~~~~~~~~~
range.rs:7:9: 7:26 error: mismatched types:
expected `u32`,
found `&'static str`
(expected u32,
found &-ptr) [E0308]
range.rs:7 "what" ... "well" => (),
^~~~~~~~~~~~~~~~~
range.rs:8:9: 8:22 error: mismatched types in range:
expected &-ptr,
found integral variable [E0211]
range.rs:8 10 ... "what" => ()
^~~~~~~~~~~~~
range.rs:8:9: 8:15 error: only char and numeric types are allowed in range [E0029]
range.rs:8 10 ... "what" => ()
^~~~~~
error: aborting due to 12 previous errors
```
The problems here are:
1. The type of the end of the range is used to predict the type of the start (only mildly counter intuitive).
2. E0029 is erroneously generated for `char ... num` and `num ... char`.
2. `u32` is mentioned.
3. Errors which are essentially the same are reported multiple times.
I've attempted to fix this by checking the requirements in a different order. The output I've achieved for the above example is:
```
/home/michael/Temp/range.rs:4:17: 4:22 error: mismatched types in range:
expected char,
found integral variable [E0211]
/home/michael/Temp/range.rs:4 'a' ... 10 => (),
^~~~~
/home/michael/Temp/range.rs:5:16: 5:22 error: mismatched types in range:
expected integral variable,
found char [E0211]
/home/michael/Temp/range.rs:5 10 ... 'z' => (),
^~~~~~
/home/michael/Temp/range.rs:6:9: 6:19 error: only char and numeric types are allowed in range [E0029]
/home/michael/Temp/range.rs:6 "what" ... 10 => (),
^~~~~~~~~~
/home/michael/Temp/range.rs:6:9: 6:19 help: run `rustc --explain E0029` to see a detailed explanation
/home/michael/Temp/range.rs:6:9: 6:19 note: Start type: &'static str
End type: _
/home/michael/Temp/range.rs:6 "what" ... 10 => (),
^~~~~~~~~~
/home/michael/Temp/range.rs:7:9: 7:26 error: only char and numeric types are allowed in range [E0029]
/home/michael/Temp/range.rs:7 "what" ... "well" => (),
^~~~~~~~~~~~~~~~~
/home/michael/Temp/range.rs:7:9: 7:26 help: run `rustc --explain E0029` to see a detailed explanation
/home/michael/Temp/range.rs:7:9: 7:26 note: Start type: &'static str
End type: &'static str
/home/michael/Temp/range.rs:7 "what" ... "well" => (),
^~~~~~~~~~~~~~~~~
/home/michael/Temp/range.rs:8:16: 8:25 error: only char and numeric types are allowed in range [E0029]
/home/michael/Temp/range.rs:8 10 ... "what" => ()
^~~~~~~~~
/home/michael/Temp/range.rs:8:16: 8:25 help: run `rustc --explain E0029` to see a detailed explanation
/home/michael/Temp/range.rs:8:16: 8:25 note: Start type: _
End type: &'static str
/home/michael/Temp/range.rs:8 10 ... "what" => ()
^~~~~~~~~
error: aborting due to 5 previous errors
```
I think this is already tonnes better, but the `Start type/End type` stuff could be neater. I don't think there's really any need to start a `note:` block but I wanted to get some feedback on this. I'd also appreciate advice on how to print the integer types as something other than `_`.
This was always a weird feature, and isn't being used in the compiler.
Static assertions should be done better than this.
This implements RFC #1096.
Fixes#13951Fixes#23008Fixes#6676
This is behind a feature gate, but that's still a
[breaking-change]
The E0397 explanation, as I've written it, isn't really an explanation, but I'm not sure what to put here. I will happily take suggestions.
Partially addresses https://github.com/rust-lang/rust/issues/25851
