Auto merge of #145701 - jhpratt:rollup-a0kg33p, r=jhpratt

Rollup of 19 pull requests

Successful merges:

 - rust-lang/rust#143383 (stabilize `const_array_each_ref`)
 - rust-lang/rust#144758 ([Doc] Add links to the various collections)
 - rust-lang/rust#144915 (Defer tail call ret ty equality to check_tail_calls)
 - rust-lang/rust#145256 (Add new `--test-codegen-backend` bootstrap option)
 - rust-lang/rust#145297 (fix(debuginfo): handle false positives in overflow check)
 - rust-lang/rust#145390 (Shorten some dependency chains in the compiler)
 - rust-lang/rust#145415 (std_detect: RISC-V: implement implication to "C")
 - rust-lang/rust#145525 (stdlib: Replace typedef -> type alias in doc comment)
 - rust-lang/rust#145590 (Prevent impossible combinations in `ast::ModKind`.)
 - rust-lang/rust#145593 (UnsafePinned::raw_get: sync signature with get)
 - rust-lang/rust#145621 (Fix some doc typos)
 - rust-lang/rust#145627 (Unconditionally-const supertraits are considered not dyn compatible)
 - rust-lang/rust#145642 (Do not use effective_visibilities query for Adt types of a local trait while proving a where-clause)
 - rust-lang/rust#145650 (Fix JS search scripts path)
 - rust-lang/rust#145654 (Download CI GCC into the correct directory)
 - rust-lang/rust#145662 (Enforce correct number of arguments for `"x86-interrupt"` functions)
 - rust-lang/rust#145673 (Add flock support for cygwin)
 - rust-lang/rust#145674 (Enable triagebot `[review-changes-since]` feature)
 - rust-lang/rust#145678 (Fix typo in docstring)

r? `@ghost`
`@rustbot` modify labels: rollup

1 files changed, 53 insertions, 0 deletions

diff --git a/compiler/rustc_error_messages/src/lib.rs b/compiler/rustc_error_messages/src/lib.rs
index 4b3ecad307f..d8bacbe762b 100644
--- a/compiler/rustc_error_messages/src/lib.rs
+++ b/compiler/rustc_error_messages/src/lib.rs
@@ -23,6 +23,9 @@ use rustc_span::Span;
 use tracing::{instrument, trace};
 pub use unic_langid::{LanguageIdentifier, langid};
 
+mod diagnostic_impls;
+pub use diagnostic_impls::DiagArgFromDisplay;
+
 pub type FluentBundle =
     IntoDynSyncSend<fluent_bundle::bundle::FluentBundle<FluentResource, IntlLangMemoizer>>;
 
@@ -589,3 +592,53 @@ pub fn fluent_value_from_str_list_sep_by_and(l: Vec<Cow<'_, str>>) -> FluentValu
 
     FluentValue::Custom(Box::new(FluentStrListSepByAnd(l)))
 }
+
+/// Simplified version of `FluentArg` that can implement `Encodable` and `Decodable`. Collection of
+/// `DiagArg` are converted to `FluentArgs` (consuming the collection) at the start of diagnostic
+/// emission.
+pub type DiagArg<'iter> = (&'iter DiagArgName, &'iter DiagArgValue);
+
+/// Name of a diagnostic argument.
+pub type DiagArgName = Cow<'static, str>;
+
+/// Simplified version of `FluentValue` that can implement `Encodable` and `Decodable`. Converted
+/// to a `FluentValue` by the emitter to be used in diagnostic translation.
+#[derive(Clone, Debug, PartialEq, Eq, Hash, Encodable, Decodable)]
+pub enum DiagArgValue {
+    Str(Cow<'static, str>),
+    // This gets converted to a `FluentNumber`, which is an `f64`. An `i32`
+    // safely fits in an `f64`. Any integers bigger than that will be converted
+    // to strings in `into_diag_arg` and stored using the `Str` variant.
+    Number(i32),
+    StrListSepByAnd(Vec<Cow<'static, str>>),
+}
+
+/// Converts a value of a type into a `DiagArg` (typically a field of an `Diag` struct).
+/// Implemented as a custom trait rather than `From` so that it is implemented on the type being
+/// converted rather than on `DiagArgValue`, which enables types from other `rustc_*` crates to
+/// implement this.
+pub trait IntoDiagArg {
+    /// Convert `Self` into a `DiagArgValue` suitable for rendering in a diagnostic.
+    ///
+    /// It takes a `path` where "long values" could be written to, if the `DiagArgValue` is too big
+    /// for displaying on the terminal. This path comes from the `Diag` itself. When rendering
+    /// values that come from `TyCtxt`, like `Ty<'_>`, they can use `TyCtxt::short_string`. If a
+    /// value has no shortening logic that could be used, the argument can be safely ignored.
+    fn into_diag_arg(self, path: &mut Option<std::path::PathBuf>) -> DiagArgValue;
+}
+
+impl IntoDiagArg for DiagArgValue {
+    fn into_diag_arg(self, _: &mut Option<std::path::PathBuf>) -> DiagArgValue {
+        self
+    }
+}
+
+impl From<DiagArgValue> for FluentValue<'static> {
+    fn from(val: DiagArgValue) -> Self {
+        match val {
+            DiagArgValue::Str(s) => From::from(s),
+            DiagArgValue::Number(n) => From::from(n),
+            DiagArgValue::StrListSepByAnd(l) => fluent_value_from_str_list_sep_by_and(l),
+        }
+    }
+}