Avoid writing a temporary closure kind
We used to write a temporary closure kind into the inference table, but
this could lead to obligations being incorrectled resolved before
inference had completed. This result could then be cached, leading to
further trouble. This patch avoids writing any closure kind until the
computation is complete.
Fixes#34349.
r? @arielb1 -- what do you think?
diagnostically note source of overruling outer forbid
When we emit E0453 (lint level attribute overruled by outer `forbid`
lint level), it could be helpful to note where the `forbid` level was
set, for the convenience of users who, e.g., believe that the correct
fix is to weaken the `forbid` to `deny`.

Suggest use of `--print target-list` when target is not found.
If given target could not be found suggest using `--print target-list`.
Previously, error has been reported as:
$ rustc --target 86-unknown-linux-gnu
error: Error loading target specification: Could not find specification for target "86-unknown-linux-gnu"
After changes it looks as follows:
$ rustc --target 86-unknown-linux-gnu
error: Error loading target specification: Could not find specification for target "x86-unknown-linux-gnu". Use `--print target-list` for a list of supported targets
If given target could not be found suggest using `--print target-list`.
Previously, error has been reported as:
$ rustc --target x86-unknown-linux-gnu
error: Error loading target specification: Could not find specification for target "x86-unknown-linux-gnu"
After changes it looks as follows:
rustc --target x86-unknown-linux-gnu
error: Error loading target specification: Could not find specification for target "x86-unknown-linux-gnu"
help: Use `--print target-list` for a list of built-in targets
When we emit E0453 (lint level attribute overruled by outer `forbid`
lint level), it could be helpful to note where the `forbid` level was
set, for the convenience of users who, e.g., believe that the correct
fix is to weaken the `forbid` to `deny`.
Rename _ to {integer} and {float} for unknown numeric types
This PR renames _ to {integer} or {float} for unknown numeric types, to help people parse error messages that have numeric types that haven't been nailed down.
Example:
```rust
fn main() {
let x: String = 4;
}
```
Before:
```
error[E0308]: mismatched types
--> quicktest.rs:2:21
|
2 | let x: String = 4;
| ^ expected struct `std::string::String`, found integral variable
|
= note: expected type `std::string::String`
= note: found type `_`
error: aborting due to previous error
```
after:
```
error[E0308]: mismatched types
--> quicktest.rs:2:21
|
2 | let x: String = 4;
| ^ expected struct `std::string::String`, found integral variable
|
= note: expected type `std::string::String`
= note: found type `{integer}`
error: aborting due to previous error
```
```
Implement ARM personality routine in Rust.
Remove the `eh_personality_catch` lang item.
Use a simplified version of `cfg_if!` in libunwind.
Closes#34786
Better attribute and metaitem encapsulation throughout the compiler
This PR refactors most (hopefully all?) of the `MetaItem` interactions outside of `libsyntax` (and a few inside) to interact with MetaItems through the provided traits instead of directly creating / destruct / matching against them. This is a necessary first step to eventually converting `MetaItem`s to internally use `TokenStream` representations (which will make `MetaItem` interactions much nicer for macro writers once the new macro system is in place).
r? @nrc
Enable reuse of `.o` files if nothing has changed
This PR completes a first "spike" for incremental compilation by enabling us to reuse `.o` files when nothing has changed. When in incr. mode, we will save `.o` files into the temporary directory, then copy them back out again if they are still valid. The code is still a bit rough but it does seem to work. =)
r? @michaelwoerister
Fixes#34036Fixes#34037Fixes#34038
In the older version, a `.o` and ` .bc` file were separate
work-products. This newer version keeps, for each codegen-unit, a set
of files of different kinds. We assume that if any kinds are available
then all the kinds we need are available, since the precise set of
switches will depend on attributes and command-line switches.
Should probably test this: the effect of changing attributes in
particular might not be successfully tracked?
We used to use `Name`, but the session outlives the tokenizer, which
means that attempts to read this field after trans has complete
otherwise panic. All reads want an `InternedString` anyhow.
A work product right now is just a `.o` file. In the future it probably
includes other kinds of files, such as `.bc` files saving the
unoptimized LLVM IR.
However, because WorkProductIds must be independent of DefIds, so that
they don't need translation, this system may not be suitable *as is* for
storing fine-grained information (such as the MIR for individual defs),
as it was originally intended. We will want to refactor some for that.
We used to write a temporary closure kind into the inference table, but
this could lead to obligations being incorrectled resolved before
inference had completed. This result could then be cached, leading to
further trouble. This patch avoids writing any closure kind until the
computation is complete.
Fixes#34349.
The type equation in projection takes place under a binder and a snapshot, which
we can't easily take types out of. Instead, when encountering a projection error,
try to re-do the projection and find the type error then.
This fails to produce a sane type error when the failure was a "leak_check" failure.
I can't think of a sane way to show *these*, so I just left them use the old crappy
representation, and added a test to make sure we don't break them.
Unfortunately, projection errors do not come with a nice set of
mismatched types. This is because the type equality check occurs
within a higher-ranked context. Therefore, only the type error
is reported. This is ugly but was always the situation.
I will introduce better errors for the lower-ranked case in
another commit.
Fixes the last known occurence of #31173
Add MIR Optimization Tests
I've starting working on the infrastructure for testing MIR optimizations.
The plan now is to have a set of test cases (written in Rust), compile them with -Z dump-mir, and check the MIR before and after each pass.
Simplify librustc_errors
This is part 2 of the error crate refactor, starting with #34403.
In this refactor, I focused on slimming down the error crate to fewer moving parts. As such, I've removed quite a few parts and replaced the with simpler, straight-line code. Specifically, this PR:
* Removes BasicEmitter
* Remove emit from emitter, leaving emit_struct
* Renames emit_struct to emit
* Removes CoreEmitter and focuses on a single Emitter
* Implements the latest changes to error format RFC (#1644)
* Removes (now-unused) code in emitter.rs and snippet.rs
* Moves more tests to the UI tester, removing some duplicate tests in the process
There is probably more that could be done with some additional refactoring, but this felt like it was getting to a good state.
r? @alexcrichton cc: @Manishearth (as there may be breaking changes in stuff I removed/changed)
Move variant_size_differences out of trans
Also enhances the error message a bit, fixes#30505 on the way, and adds
a test (which was missing).
Closes#34018