rust/compiler/rustc_hir_analysis
Nicholas Nethercote 781111ef35 Use Cow in {D,Subd}iagnosticMessage.
Each of `{D,Subd}iagnosticMessage::{Str,Eager}` has a comment:
```
// FIXME(davidtwco): can a `Cow<'static, str>` be used here?
```
This commit answers that question in the affirmative. It's not the most
compelling change ever, but it might be worth merging.

This requires changing the `impl<'a> From<&'a str>` impls to `impl
From<&'static str>`, which involves a bunch of knock-on changes that
require/result in call sites being a little more precise about exactly
what kind of string they use to create errors, and not just `&str`. This
will result in fewer unnecessary allocations, though this will not have
any notable perf effects given that these are error paths.

Note that I was lazy within Clippy, using `to_string` in a few places to
preserve the existing string imprecision. I could have used `impl
Into<{D,Subd}iagnosticMessage>` in various places as is done in the
compiler, but that would have required changes to *many* call sites
(mostly changing `&format("...")` to `format!("...")`) which didn't seem
worthwhile.
2023-05-29 09:23:43 +10:00
..
src Use Cow in {D,Subd}iagnosticMessage. 2023-05-29 09:23:43 +10:00
Cargo.toml drop unused deps, gate libc under unix for one crate 2023-04-22 15:22:21 +03:00
messages.ftl Ensure Fluent messages are in alphabetical order 2023-05-25 23:49:35 +00:00
README.md rustc_typeck to rustc_hir_analysis 2022-09-27 10:37:23 +02:00

For high-level intro to how type checking works in rustc, see the type checking chapter of the rustc dev guide.