Currently a `{D,Subd}iagnosticMessage` can be created from any type that
impls `Into<String>`. That includes `&str`, `String`, and `Cow<'static,
str>`, which are reasonable. It also includes `&String`, which is pretty
weird, and results in many places making unnecessary allocations for
patterns like this:
```
self.fatal(&format!(...))
```
This creates a string with `format!`, takes a reference, passes the
reference to `fatal`, which does an `into()`, which clones the
reference, doing a second allocation. Two allocations for a single
string, bleh.
This commit changes the `From` impls so that you can only create a
`{D,Subd}iagnosticMessage` from `&str`, `String`, or `Cow<'static,
str>`. This requires changing all the places that currently create one
from a `&String`. Most of these are of the `&format!(...)` form
described above; each one removes an unnecessary static `&`, plus an
allocation when executed. There are also a few places where the existing
use of `&String` was more reasonable; these now just use `clone()` at
the call site.
As well as making the code nicer and more efficient, this is a step
towards possibly using `Cow<'static, str>` in
`{D,Subd}iagnosticMessage::{Str,Eager}`. That would require changing
the `From<&'a str>` impls to `From<&'static str>`, which is doable, but
I'm not yet sure if it's worthwhile.
Fluent, with all the icu4x it brings in, takes quite some time to
compile. `fluent_messages!` is only needed in further downstream rustc
crates, but is blocking more upstream crates like `rustc_index`. By
splitting it out, we allow `rustc_macros` to be compiled earlier, which
speeds up `x check compiler` by about 5 seconds (and even more after the
needless dependency on `serde_json` is removed from
`rustc_data_structures`).
This makes it easier to open the messages file while developing on features.
The commit was the result of automatted changes:
for p in compiler/rustc_*; do mv $p/locales/en-US.ftl $p/messages.ftl; rmdir $p/locales; done
for p in compiler/rustc_*; do sed -i "s#\.\./locales/en-US.ftl#../messages.ftl#" $p/src/lib.rs; done
Instead of loading the Fluent resources for every crate in
`rustc_error_messages`, each crate generates typed identifiers for its
own diagnostics and creates a static which are pulled together in the
`rustc_driver` crate and provided to the diagnostic emitter.
Signed-off-by: David Wood <david.wood@huawei.com>
Convert all the crates that have had their diagnostic migration
completed (except save_analysis because that will be deleted soon and
apfloat because of the licensing problem).
FIX - ambiguous Diagnostic link in docs
UPDATE - rename diagnostic_items to IntoDiagnostic and AddToDiagnostic
[Gardening] FIX - formatting via `x fmt`
FIX - rebase conflicts. NOTE: Confirm wheather or not we want to handle TargetDataLayoutErrorsWrapper this way
DELETE - unneeded allow attributes in Handler method
FIX - broken test
FIX - Rebase conflict
UPDATE - rename residual _SessionDiagnostic and fix LintDiag link
On later stages, the feature is already stable.
Result of running:
rg -l "feature.let_else" compiler/ src/librustdoc/ library/ | xargs sed -s -i "s#\\[feature.let_else#\\[cfg_attr\\(bootstrap, feature\\(let_else\\)#"
Suggested by the team in this Zulip Topic https://rust-lang.zulipchat.com/#narrow/stream/336883-i18n/topic/.23100717.20SessionDiagnostic.20on.20Handler
Handler already has almost all the capabilities of ParseSess when it comes to diagnostic emission, in this migration we only needed to add the ability to access source_map from the emitter in order to get a Snippet and the start_point. Not sure if this is the best way to address this gap
This attribute allows to mark default body of a trait function as
unstable. This means that implementing the trait without implementing
the function will require enabling unstable feature.
This is useful in conjunction with `#[rustc_must_implement_one_of]`,
we may want to relax requirements for a trait, for example allowing
implementing either of `PartialEq::{eq, ne}`, but do so in a safe way
-- making implementation of only `PartialEq::ne` unstable.
If part of a feature is stabilized and a new feature is added for the
remaining parts, then the `implied_by` attribute can be used to indicate
which now-stable feature previously contained a item. If the now-stable
feature is still active (if the user has only just updated rustc, for
example) then there will not be an stability error for uses of the item
from the implied feature.
Signed-off-by: David Wood <david.wood@huawei.com>
When an unexpected meta item is provided to `#[stable]`, the diagnostic
lists "since" and "note" as expected meta-items, however the surrounding
code actually expects "feature" and "since".
Signed-off-by: David Wood <david.wood@huawei.com>
