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781111ef35
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.
25 lines
726 B
Rust
25 lines
726 B
Rust
// The compiler code necessary to support the compile_error! extension.
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use rustc_ast::tokenstream::TokenStream;
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use rustc_expand::base::{self, *};
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use rustc_span::Span;
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pub fn expand_compile_error<'cx>(
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cx: &'cx mut ExtCtxt<'_>,
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sp: Span,
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tts: TokenStream,
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) -> Box<dyn base::MacResult + 'cx> {
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let Some(var) = get_single_str_from_tts(cx, sp, tts, "compile_error!") else {
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return DummyResult::any(sp);
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};
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#[expect(
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rustc::diagnostic_outside_of_impl,
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reason = "diagnostic message is specified by user"
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)]
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#[expect(rustc::untranslatable_diagnostic, reason = "diagnostic message is specified by user")]
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cx.span_err(sp, var.to_string());
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DummyResult::any(sp)
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}
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