Related: #66426
This commit adds handling for opaque types during inference variable
fallback. Type variables generated from the instantiatino of opaque
types now fallback to the opque type itself.
Normally, the type variable for an instantiated opaque type is either
unified with the concrete type, or with the opaque type itself (e.g when
a function returns an opaque type by calling another function).
However, it's possible for the type variable to be left completely
unconstrained. This can occur in code like this:
```rust
pub type Foo = impl Copy;
fn produce() -> Option<Foo> {
None
}
```
Here, we'll instantatiate the `Foo` in `Option<Foo>` to a fresh type
variable, but we will never unify it with anything due to the fact
that we return a `None`.
This results in the error message:
`type annotations needed: cannot resolve `_: std::marker::Copy``
pointing at `pub type Foo = impl Copy`.
This message is not only confusing, it's incorrect. When an opaque type
inference variable is completely unconstrained, we can always fall back
to using the opaque type itself. This effectively turns that particular
use of the opaque type into a non-defining use, even if it appears in a
defining scope.
Push `ast::{ItemKind, ImplItemKind}::OpaqueTy` hack down into lowering
We currently have a hack in the form of `ast::{ItemKind, ImplItemKind}::OpaqueTy` which is constructed literally when you write `type Alias = impl Trait;` but not e.g. `type Alias = Vec<impl Trait>;`. Per https://github.com/rust-lang/rfcs/pull/2515, this needs to change to allow `impl Trait` in nested positions. This PR achieves this change for the syntactic aspect but not the semantic one, which will require changes in lowering and def collection. In the interim, `TyKind::opaque_top_hack` is introduced to avoid knock-on changes in lowering, collection, and resolve. These hacks can then be removed and fixed one by one until the desired semantics are supported.
r? @varkor
Remove cannot mutate statics in initializer of another static error
r? @oli-obk
This is just a refactoring. As the removed code itself said, it only a heuristic catching a few cases early instead of leaving it all to const eval. It's easy to work around the static check and then run into the miri-engine check.
Move error codes
Works towards #66210.
r? @Centril
Oh btw, for the ones interested, I used this python script to get all error codes content sorted into one final file:
<details>
```python
from os import listdir
from os.path import isdir, isfile, join
def get_error_codes(error_codes, f_path):
with open(f_path) as f:
short_mode = False
lines = f.read().split("\n")
i = 0
while i < len(lines):
line = lines[i]
if not short_mode and line.startswith("E0") and line.endswith(": r##\""):
error = line
error += "\n"
i += 1
while i < len(lines):
line = lines[i]
error += line
if line.endswith("\"##,"):
break
error += "\n"
i += 1
error_codes["long"].append(error)
elif line == ';':
short_mode = True
elif short_mode is True and len(line) > 0 and line != "}":
error_codes["short"].append(line)
while i + 1 < len(lines):
line = lines[i + 1].strip()
if not line.startswith("//"):
break
parts = line.split("//")
if len(parts) < 2:
break
if parts[1].strip().startswith("E0"):
break
error_codes["short"][-1] += "\n"
error_codes["short"][-1] += lines[i + 1]
i += 1
i += 1
def loop_dirs(error_codes, cur_dir):
for entry in listdir(cur_dir):
f = join(cur_dir, entry)
if isfile(f) and entry == "error_codes.rs":
get_error_codes(error_codes, f)
elif isdir(f) and not entry.startswith("librustc_error_codes"):
loop_dirs(error_codes, f)
def get_error_code(err):
x = err.split(",")
if len(x) < 2:
return err
x = x[0]
if x.strip().startswith("//"):
x = x.split("//")[1].strip()
return x.strip()
def write_into_file(error_codes, f_path):
with open(f_path, "w") as f:
f.write("// Error messages for EXXXX errors. Each message should start and end with a\n")
f.write("// new line, and be wrapped to 80 characters. In vim you can `:set tw=80` and\n")
f.write("// use `gq` to wrap paragraphs. Use `:set tw=0` to disable.\n\n")
f.write("syntax::register_diagnostics! {\n\n")
error_codes["long"].sort()
for i in error_codes["long"]:
f.write(i)
f.write("\n\n")
f.write(";\n")
error_codes["short"] = sorted(error_codes["short"], key=lambda err: get_error_code(err))
for i in error_codes["short"]:
f.write(i)
f.write("\n")
f.write("}\n")
error_codes = {
"long": [],
"short": []
}
loop_dirs(error_codes, "src")
write_into_file(error_codes, "src/librustc_error_codes/src/error_codes.rs")
```
</details>
And to move the error codes into their own files:
<details>
```python
import os
try:
os.mkdir("src/librustc_error_codes/error_codes")
except OSError:
print("Seems like folder already exist, moving on!")
data = ''
with open("src/librustc_error_codes/error_codes.rs") as f:
x = f.read().split('\n')
i = 0
short_part = False
while i < len(x):
line = x[i]
if short_part is False and line.startswith('E0') and line.endswith(': r##"'):
err_code = line.split(':')[0]
i += 1
content = ''
while i < len(x):
if x[i] == '"##,':
break
content += x[i]
content += '\n'
i += 1
f_path = "src/librustc_error_codes/error_codes/{}.md".format(err_code)
with open(f_path, "w") as ff:
ff.write(content)
data += '{}: include_str!("./error_codes/{}.md"),'.format(err_code, err_code)
elif short_part is False and line == ';':
short_part is True
data += ';\n'
else:
data += line
data += '\n'
i += 1
with open("src/librustc_error_codes/error_codes.rs", "w") as f:
f.write(data)
```
</details>
Rollup of 9 pull requests
Successful merges:
- #66253 (Improve errors after re rebalance coherence)
- #66264 (fix an ICE in macro's diagnostic message)
- #66349 (expand source_util macros with def-site context)
- #66351 (Tweak non-char/numeric in range pattern diagnostic)
- #66360 (Fix link to Exten in Vec::set_len)
- #66361 (parser: don't use `unreachable!()` in `fn unexpected`.)
- #66363 (Improve error message in make_tests)
- #66369 (compiletest: Obtain timestamps for common inputs only once)
- #66372 (Fix broken links in Ipv4Addr::is_benchmarking docs)
Failed merges:
r? @ghost
fix an ICE in macro's diagnostic message
This has two small fixes:
1. for the left brace, we don't need `<space>{`, simply `{` is enough.
2. for the right brace, it tries to peel off one character even when the close delim is missing. Without this fix, it would crash in some cases. (as shown in the new test case)
r? @estebank
Improve errors after re rebalance coherence
Following #65247, I noticed that some error messages should be updated to reflect the changes of `re_rebalance_coherence` (also there was a [note](https://rust-lang.github.io/rfcs/2451-re-rebalancing-coherence.html#teaching-users) in the RFC about it).
First, error message `E0210` was updated to match the RFC, and I also tried to improve a little the error when the "order" of types is problematic.
For code like this:
```
#![feature(re_rebalance_coherence)] // Now stable
struct Wrap<T>(T);
impl<T> From<Wrap<T>> for T {
fn from(x: Wrap<T>) -> T {
x.0
}
}
```
The old error was:
```
error[E0210]: type parameter `T` must be used as the type parameter for some local type (e.g., `MyStruct<T>`)
--> src/lib.rs:5:6
|
5 | impl<T> From<Wrap<T>> for T {
| ^ type parameter `T` must be used as the type parameter for some local type
|
= note: only traits defined in the current crate can be implemented for a type parameter
```
and the new error is:
```
error[E0210]: type parameter `T` must be covered by another type when it appears before the first local type (`Wrap<T>`)
--> main.rs:66:6
|
66 | impl<T> From<Wrap<T>> for T {
| ^ type parameter `T` must be covered by another type when it appears before the first local type (`Wrap<T>`)
|
= note: implementing a foreign trait is only possible if at least one of the types for which is it implemented is local, and no uncovered type parameters appear before that first local type
= note: in this case, 'before' refers to the following order: `impl<..> ForeignTrait<T1, ..., Tn> for T0`, where `T0` is the first and `Tn` is the last
```
I tried to point at the uncovered `T`, but couldn't get something which was reliable (but I'll be happy to try if someone points me in the right direction).
r? @estebank
cc @nikomatsakis
Fixes#65247
Split ConstValue into two enums
Hello,
Issue #59210 appeared abandoned, so I gave it a go.
Some further cleanup and refactoring may be mandated.
I did not test beyond `x.py check`, since my home computer dies compiling librustc.
Fixes#59210
Fix ICE when documentation includes intra-doc-link
When collecting intra-doc-links we could trigger the loading of extra crates into the crate store due to name resolution finding crates referred to in documentation but not in code. This might be due to
configuration differences or simply referring to something else.
This would cause an ICE because the newly loaded crate metadata existed in a crate store associated with the rustdoc global context, but the resolver had its own crate store cloned just before the documentation processing began and as such it could try and look up crates in a store which lacked them.
In this PR, I add support for `--extern-private` to the `rustdoc` tool so that it is supported for `compiletest` to then pass the crates in; and then I fix the issue by forcing the resolver to look over all the crates before we then lower the input ready for processing into documentation.
The first commit (the `--extern-private`) could be replaced with a commit which adds support for `--extern` to `compiletest` if preferred, though I think that adding `--extern-private` to `rustdoc` is more useful anyway since it makes the CLI a little more like `rustc`'s which might help reduce surprise for someone running it by hand or in their own test code.
The PR is meant to fix#66159 though it may also fix#65840.
cc @GuillaumeGomez
This PR BREAKS CODE THAT WAS ACCEPTED ON STABLE. It's arguably a bug
that this was accepted in the first place, but here we are. See #62272
for more info.
These errors will be triggered before the MIR const-checker runs,
causing all other errors to be silenced. They are now checked in the
`const-{if,loop}` tests.
Add some tests for fixed ICEs
Closes#30904 (fixed between nightly-2019-07-14 and nightly-2019-07-31)
Closes#40231 (example 1 is fixed in 1.32.0, example 2 is fixed in 1.38.0)
Closes#52432 (fixed in rustc 1.40.0-beta.1 (76b40532a 2019-11-05))
Closes#63279 (fixed in rustc 1.40.0-nightly (246be7e1a 2019-10-25))
r? @Centril
Add a callback that allows compiler consumers to override queries.
This pull request adds an additional callback that allows compiler consumers such as Prusti and MIRAI to override queries. My hope is that in this way it will be possible to get access to the internal compiler information (e.g. borrow checker) without major changes to the compiler.
This pull request is work in progress because I am still testing if I can get the information which I need.
cc @nikomatsakis
r? @oli-obk
Fix MIR lowering evaluation order and soundness bug
* Fixes a soundness issue with built-in index operations
* Ensures correct evaluation order of assignment expressions where the RHS is a FRU or is a use of a local of reference type.
* Removes an unnecessary symbol to string conversion
closes#65909closes#65910
support issue = "none" in unstable attributes
This works towards fixing #41260.
This PR allows the use of `issue = "none"` in unstable attributes and makes changes to internally store the issue number as an `Option<NonZeroU32>`. For example:
```rust
#[unstable(feature = "unstable_test_feature", issue = "none")]
fn unstable_issue_none() {}
```
It was not made optional because feedback seen here #60860 suggested that people might forget the issue field if it was optional.
I could not remove the current uses of `issue = "0"` (of which there are a lot) because the stage 0 compiler expects the old syntax. Once this is available in the stage 0 compiler we can replace all uses of `"0"` with `"none"` and no longer allow `"0"`. This is my first time contributing, so I'm not sure what the protocol is with two-part things like this, so some guidance would be appreciated.
r? @varkor
