b5d3d970fa
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`).
65 lines
2.3 KiB
Rust
65 lines
2.3 KiB
Rust
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
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#![feature(proc_macro_diagnostic)]
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#![feature(proc_macro_span)]
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#![deny(rustc::untranslatable_diagnostic)]
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#![deny(rustc::diagnostic_outside_of_impl)]
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#![allow(rustc::default_hash_types)]
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use proc_macro::TokenStream;
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mod fluent;
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/// Implements the `fluent_messages` macro, which performs compile-time validation of the
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/// compiler's Fluent resources (i.e. that the resources parse and don't multiply define the same
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/// messages) and generates constants that make using those messages in diagnostics more ergonomic.
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///
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/// For example, given the following invocation of the macro..
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///
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/// ```ignore (rust)
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/// fluent_messages! { "./typeck.ftl" }
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/// ```
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/// ..where `typeck.ftl` has the following contents..
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///
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/// ```fluent
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/// typeck_field_multiply_specified_in_initializer =
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/// field `{$ident}` specified more than once
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/// .label = used more than once
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/// .label_previous_use = first use of `{$ident}`
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/// ```
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/// ...then the macro parse the Fluent resource, emitting a diagnostic if it fails to do so, and
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/// will generate the following code:
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///
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/// ```ignore (rust)
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/// pub static DEFAULT_LOCALE_RESOURCE: &'static [&'static str] = include_str!("./typeck.ftl");
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///
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/// mod fluent_generated {
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/// mod typeck {
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/// pub const field_multiply_specified_in_initializer: DiagnosticMessage =
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/// DiagnosticMessage::fluent("typeck_field_multiply_specified_in_initializer");
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/// pub const field_multiply_specified_in_initializer_label_previous_use: DiagnosticMessage =
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/// DiagnosticMessage::fluent_attr(
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/// "typeck_field_multiply_specified_in_initializer",
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/// "previous_use_label"
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/// );
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/// }
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/// }
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/// ```
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/// When emitting a diagnostic, the generated constants can be used as follows:
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///
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/// ```ignore (rust)
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/// let mut err = sess.struct_span_err(
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/// span,
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/// fluent::typeck::field_multiply_specified_in_initializer
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/// );
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/// err.span_default_label(span);
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/// err.span_label(
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/// previous_use_span,
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/// fluent::typeck::field_multiply_specified_in_initializer_label_previous_use
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/// );
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/// err.emit();
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/// ```
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#[proc_macro]
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pub fn fluent_messages(input: TokenStream) -> TokenStream {
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fluent::fluent_messages(input)
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}
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