1 files changed, 159 insertions, 0 deletions
diff --git a/compiler/rustc_macros/src/diagnostics/mod.rs b/compiler/rustc_macros/src/diagnostics/mod.rs
new file mode 100644
index 000000000..399790026
--- /dev/null
+++ b/compiler/rustc_macros/src/diagnostics/mod.rs
@@ -0,0 +1,159 @@
+mod diagnostic;
+mod diagnostic_builder;
+mod error;
+mod fluent;
+mod subdiagnostic;
+mod utils;
+
+use diagnostic::{LintDiagnosticDerive, SessionDiagnosticDerive};
+pub(crate) use fluent::fluent_messages;
+use proc_macro2::TokenStream;
+use quote::format_ident;
+use subdiagnostic::SessionSubdiagnosticDerive;
+use synstructure::Structure;
+
+/// Implements `#[derive(SessionDiagnostic)]`, which allows for errors to be specified as a struct,
+/// independent from the actual diagnostics emitting code.
+///
+/// ```ignore (rust)
+/// # extern crate rustc_errors;
+/// # use rustc_errors::Applicability;
+/// # extern crate rustc_span;
+/// # use rustc_span::{symbol::Ident, Span};
+/// # extern crate rust_middle;
+/// # use rustc_middle::ty::Ty;
+/// #[derive(SessionDiagnostic)]
+/// #[error(borrowck::move_out_of_borrow, code = "E0505")]
+/// pub struct MoveOutOfBorrowError<'tcx> {
+///     pub name: Ident,
+///     pub ty: Ty<'tcx>,
+///     #[primary_span]
+///     #[label]
+///     pub span: Span,
+///     #[label(borrowck::first_borrow_label)]
+///     pub first_borrow_span: Span,
+///     #[suggestion(code = "{name}.clone()")]
+///     pub clone_sugg: Option<(Span, Applicability)>
+/// }
+/// ```
+///
+/// ```fluent
+/// move-out-of-borrow = cannot move out of {$name} because it is borrowed
+///     .label = cannot move out of borrow
+///     .first-borrow-label = `{$ty}` first borrowed here
+///     .suggestion = consider cloning here
+/// ```
+///
+/// Then, later, to emit the error:
+///
+/// ```ignore (rust)
+/// sess.emit_err(MoveOutOfBorrowError {
+///     expected,
+///     actual,
+///     span,
+///     first_borrow_span,
+///     clone_sugg: Some(suggestion, Applicability::MachineApplicable),
+/// });
+/// ```
+///
+/// See rustc dev guide for more examples on using the `#[derive(SessionDiagnostic)]`:
+/// <https://rustc-dev-guide.rust-lang.org/diagnostics/diagnostic-structs.html>
+pub fn session_diagnostic_derive(s: Structure<'_>) -> TokenStream {
+    SessionDiagnosticDerive::new(format_ident!("diag"), format_ident!("sess"), s).into_tokens()
+}
+
+/// Implements `#[derive(LintDiagnostic)]`, which allows for lints to be specified as a struct,
+/// independent from the actual lint emitting code.
+///
+/// ```ignore (rust)
+/// #[derive(LintDiagnostic)]
+/// #[lint(lint::atomic_ordering_invalid_fail_success)]
+/// pub struct AtomicOrderingInvalidLint {
+///     method: Symbol,
+///     success_ordering: Symbol,
+///     fail_ordering: Symbol,
+///     #[label(lint::fail_label)]
+///     fail_order_arg_span: Span,
+///     #[label(lint::success_label)]
+///     #[suggestion(
+///         code = "std::sync::atomic::Ordering::{success_suggestion}",
+///         applicability = "maybe-incorrect"
+///     )]
+///     success_order_arg_span: Span,
+/// }
+/// ```
+///
+/// ```fluent
+/// lint-atomic-ordering-invalid-fail-success = `{$method}`'s success ordering must be at least as strong as its failure ordering
+///     .fail-label = `{$fail_ordering}` failure ordering
+///     .success-label = `{$success_ordering}` success ordering
+///     .suggestion = consider using `{$success_suggestion}` success ordering instead
+/// ```
+///
+/// Then, later, to emit the error:
+///
+/// ```ignore (rust)
+/// cx.struct_span_lint(INVALID_ATOMIC_ORDERING, fail_order_arg_span, AtomicOrderingInvalidLint {
+///     method,
+///     success_ordering,
+///     fail_ordering,
+///     fail_order_arg_span,
+///     success_order_arg_span,
+/// });
+/// ```
+///
+/// See rustc dev guide for more examples on using the `#[derive(LintDiagnostic)]`:
+/// <https://rustc-dev-guide.rust-lang.org/diagnostics/sessiondiagnostic.html>
+pub fn lint_diagnostic_derive(s: Structure<'_>) -> TokenStream {
+    LintDiagnosticDerive::new(format_ident!("diag"), s).into_tokens()
+}
+
+/// Implements `#[derive(SessionSubdiagnostic)]`, which allows for labels, notes, helps and
+/// suggestions to be specified as a structs or enums, independent from the actual diagnostics
+/// emitting code or diagnostic derives.
+///
+/// ```ignore (rust)
+/// #[derive(SessionSubdiagnostic)]
+/// pub enum ExpectedIdentifierLabel<'tcx> {
+///     #[label(parser::expected_identifier)]
+///     WithoutFound {
+///         #[primary_span]
+///         span: Span,
+///     }
+///     #[label(parser::expected_identifier_found)]
+///     WithFound {
+///         #[primary_span]
+///         span: Span,
+///         found: String,
+///     }
+/// }
+///
+/// #[derive(SessionSubdiagnostic)]
+/// #[suggestion_verbose(parser::raw_identifier)]
+/// pub struct RawIdentifierSuggestion<'tcx> {
+///     #[primary_span]
+///     span: Span,
+///     #[applicability]
+///     applicability: Applicability,
+///     ident: Ident,
+/// }
+/// ```
+///
+/// ```fluent
+/// parser-expected-identifier = expected identifier
+///
+/// parser-expected-identifier-found = expected identifier, found {$found}
+///
+/// parser-raw-identifier = escape `{$ident}` to use it as an identifier
+/// ```
+///
+/// Then, later, to add the subdiagnostic:
+///
+/// ```ignore (rust)
+/// diag.subdiagnostic(ExpectedIdentifierLabel::WithoutFound { span });
+///
+/// diag.subdiagnostic(RawIdentifierSuggestion { span, applicability, ident });
+/// ```
+pub fn session_subdiagnostic_derive(s: Structure<'_>) -> TokenStream {
+    SessionSubdiagnosticDerive::new(s).into_tokens()
+}