Remove the lifetime from DiagnosticArgValue.

Because it's almost always static.

This makes `impl IntoDiagnosticArg for DiagnosticArgValue` trivial,
which is nice.

There are a few diagnostics constructed in
`compiler/rustc_mir_build/src/check_unsafety.rs` and
`compiler/rustc_mir_transform/src/errors.rs` that now need symbols
converted to `String` with `to_string` instead of `&str` with `as_str`,
but that' no big deal, and worth it for the simplifications elsewhere.

Author: nnethercote

compiler/rustc_borrowck/src/diagnostics/region_name.rs

@@ -188,7 +188,7 @@ impl Display for RegionName {
 }
 
 impl rustc_errors::IntoDiagnosticArg for RegionName {
-    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue {
         self.to_string().into_diagnostic_arg()
     }
 }

compiler/rustc_codegen_gcc/src/errors.rs

@@ -35,7 +35,7 @@ pub(crate) enum PossibleFeature<'a> {
 struct ExitCode(Option<i32>);
 
 impl IntoDiagnosticArg for ExitCode {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         let ExitCode(exit_code) = self;
         match exit_code {
             Some(t) => t.into_diagnostic_arg(),

compiler/rustc_codegen_ssa/src/assert_module_sources.rs

@@ -206,7 +206,7 @@ impl fmt::Display for CguReuse {
 }
 
 impl IntoDiagnosticArg for CguReuse {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Owned(self.to_string()))
     }
 }

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -999,7 +999,7 @@ type DiagnosticArgName<'source> = Cow<'source, str>;
 
 struct Diagnostic {
     msgs: Vec<(DiagnosticMessage, Style)>,
-    args: FxHashMap<DiagnosticArgName<'static>, rustc_errors::DiagnosticArgValue<'static>>,
+    args: FxHashMap<DiagnosticArgName<'static>, rustc_errors::DiagnosticArgValue>,
     code: Option<ErrCode>,
     lvl: Level,
 }
@@ -1811,7 +1811,7 @@ impl Translate for SharedEmitter {
 
 impl Emitter for SharedEmitter {
     fn emit_diagnostic(&mut self, diag: &rustc_errors::Diagnostic) {
-        let args: FxHashMap<Cow<'_, str>, rustc_errors::DiagnosticArgValue<'_>> =
+        let args: FxHashMap<Cow<'_, str>, rustc_errors::DiagnosticArgValue> =
             diag.args().map(|(name, arg)| (name.clone(), arg.clone())).collect();
         drop(self.sender.send(SharedEmitterMessage::Diagnostic(Diagnostic {
             msgs: diag.messages.clone(),

compiler/rustc_codegen_ssa/src/errors.rs

@@ -147,7 +147,7 @@ impl<'a> CopyPath<'a> {
 struct DebugArgPath<'a>(pub &'a Path);
 
 impl IntoDiagnosticArg for DebugArgPath<'_> {
-    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Owned(format!("{:?}", self.0)))
     }
 }
@@ -974,7 +974,7 @@ pub enum ExpectedPointerMutability {
 }
 
 impl IntoDiagnosticArg for ExpectedPointerMutability {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         match self {
             ExpectedPointerMutability::Mut => DiagnosticArgValue::Str(Cow::Borrowed("*mut")),
             ExpectedPointerMutability::Not => DiagnosticArgValue::Str(Cow::Borrowed("*_")),

compiler/rustc_const_eval/src/const_eval/error.rs

@@ -34,7 +34,7 @@ impl MachineStopType for ConstEvalErrKind {
     }
     fn add_args(
         self: Box<Self>,
-        adder: &mut dyn FnMut(std::borrow::Cow<'static, str>, DiagnosticArgValue<'static>),
+        adder: &mut dyn FnMut(std::borrow::Cow<'static, str>, DiagnosticArgValue),
     ) {
         use ConstEvalErrKind::*;
         match *self {

compiler/rustc_const_eval/src/errors.rs

@@ -906,7 +906,7 @@ impl ReportErrorExt for ResourceExhaustionInfo {
 }
 
 impl rustc_errors::IntoDiagnosticArg for InternKind {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Borrowed(match self {
             InternKind::Static(Mutability::Not) => "static",
             InternKind::Static(Mutability::Mut) => "static_mut",

compiler/rustc_errors/src/diagnostic.rs

@@ -24,42 +24,36 @@ pub struct SuggestionsDisabled;
 /// `DiagnosticArg` are converted to `FluentArgs` (consuming the collection) at the start of
 /// diagnostic emission.
 pub type DiagnosticArg<'iter, 'source> =
-    (&'iter DiagnosticArgName<'source>, &'iter DiagnosticArgValue<'source>);
+    (&'iter DiagnosticArgName<'source>, &'iter DiagnosticArgValue);
 
 /// Name of a diagnostic argument.
 pub type DiagnosticArgName<'source> = Cow<'source, 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 DiagnosticArgValue<'source> {
-    Str(Cow<'source, str>),
+pub enum DiagnosticArgValue {
+    Str(Cow<'static, str>),
     Number(i128),
-    StrListSepByAnd(Vec<Cow<'source, str>>),
+    StrListSepByAnd(Vec<Cow<'static, str>>),
 }
 
 /// Converts a value of a type into a `DiagnosticArg` (typically a field of an `IntoDiagnostic`
 /// struct). Implemented as a custom trait rather than `From` so that it is implemented on the type
 /// being converted rather than on `DiagnosticArgValue`, which enables types from other `rustc_*`
 /// crates to implement this.
 pub trait IntoDiagnosticArg {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static>;
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue;
 }
 
-impl<'source> IntoDiagnosticArg for DiagnosticArgValue<'source> {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        match self {
-            DiagnosticArgValue::Str(s) => DiagnosticArgValue::Str(Cow::Owned(s.into_owned())),
-            DiagnosticArgValue::Number(n) => DiagnosticArgValue::Number(n),
-            DiagnosticArgValue::StrListSepByAnd(l) => DiagnosticArgValue::StrListSepByAnd(
-                l.into_iter().map(|s| Cow::Owned(s.into_owned())).collect(),
-            ),
-        }
+impl IntoDiagnosticArg for DiagnosticArgValue {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
+        self
     }
 }
 
-impl<'source> Into<FluentValue<'source>> for DiagnosticArgValue<'source> {
-    fn into(self) -> FluentValue<'source> {
+impl Into<FluentValue<'static>> for DiagnosticArgValue {
+    fn into(self) -> FluentValue<'static> {
         match self {
             DiagnosticArgValue::Str(s) => From::from(s),
             DiagnosticArgValue::Number(n) => From::from(n),
@@ -109,7 +103,7 @@ pub struct Diagnostic {
     pub span: MultiSpan,
     pub children: Vec<SubDiagnostic>,
     pub suggestions: Result<Vec<CodeSuggestion>, SuggestionsDisabled>,
-    args: FxHashMap<DiagnosticArgName<'static>, DiagnosticArgValue<'static>>,
+    args: FxHashMap<DiagnosticArgName<'static>, DiagnosticArgValue>,
 
     /// This is not used for highlighting or rendering any error message. Rather, it can be used
     /// as a sort key to sort a buffer of diagnostics. By default, it is the primary span of
@@ -931,7 +925,7 @@ impl Diagnostic {
 
     pub fn replace_args(
         &mut self,
-        args: FxHashMap<DiagnosticArgName<'static>, DiagnosticArgValue<'static>>,
+        args: FxHashMap<DiagnosticArgName<'static>, DiagnosticArgValue>,
     ) {
         self.args = args;
     }
@@ -990,7 +984,7 @@ impl Diagnostic {
     ) -> (
         &Level,
         &[(DiagnosticMessage, Style)],
-        Vec<(&Cow<'static, str>, &DiagnosticArgValue<'static>)>,
+        Vec<(&Cow<'static, str>, &DiagnosticArgValue)>,
         &Option<ErrCode>,
         &Option<IsLint>,
         &MultiSpan,

compiler/rustc_errors/src/diagnostic_impls.rs

@@ -23,7 +23,7 @@ use std::process::ExitStatus;
 pub struct DiagnosticArgFromDisplay<'a>(pub &'a dyn fmt::Display);
 
 impl IntoDiagnosticArg for DiagnosticArgFromDisplay<'_> {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         self.0.to_string().into_diagnostic_arg()
     }
 }
@@ -41,7 +41,7 @@ impl<'a, T: fmt::Display> From<&'a T> for DiagnosticArgFromDisplay<'a> {
 }
 
 impl<'a, T: Clone + IntoDiagnosticArg> IntoDiagnosticArg for &'a T {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         self.clone().into_diagnostic_arg()
     }
 }
@@ -50,7 +50,7 @@ macro_rules! into_diagnostic_arg_using_display {
     ($( $ty:ty ),+ $(,)?) => {
         $(
             impl IntoDiagnosticArg for $ty {
-                fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+                fn into_diagnostic_arg(self) -> DiagnosticArgValue {
                     self.to_string().into_diagnostic_arg()
                 }
             }
@@ -62,7 +62,7 @@ macro_rules! into_diagnostic_arg_for_number {
     ($( $ty:ty ),+ $(,)?) => {
         $(
             impl IntoDiagnosticArg for $ty {
-                fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+                fn into_diagnostic_arg(self) -> DiagnosticArgValue {
                     // HACK: `FluentNumber` the underline backing struct represent
                     // numbers using a f64 which can't represent all the i128 numbers
                     // So in order to be able to use fluent selectors and still
@@ -99,7 +99,7 @@ into_diagnostic_arg_using_display!(
 into_diagnostic_arg_for_number!(i8, u8, i16, u16, i32, u32, i64, u64, i128, u128, isize, usize);
 
 impl IntoDiagnosticArg for bool {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         if self {
             DiagnosticArgValue::Str(Cow::Borrowed("true"))
         } else {
@@ -109,63 +109,63 @@ impl IntoDiagnosticArg for bool {
 }
 
 impl IntoDiagnosticArg for char {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Owned(format!("{self:?}")))
     }
 }
 
 impl IntoDiagnosticArg for Vec<char> {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::StrListSepByAnd(
             self.into_iter().map(|c| Cow::Owned(format!("{c:?}"))).collect(),
         )
     }
 }
 
 impl IntoDiagnosticArg for Symbol {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         self.to_ident_string().into_diagnostic_arg()
     }
 }
 
 impl<'a> IntoDiagnosticArg for &'a str {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         self.to_string().into_diagnostic_arg()
     }
 }
 
 impl IntoDiagnosticArg for String {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Owned(self))
     }
 }
 
 impl<'a> IntoDiagnosticArg for Cow<'a, str> {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Owned(self.into_owned()))
     }
 }
 
 impl<'a> IntoDiagnosticArg for &'a Path {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Owned(self.display().to_string()))
     }
 }
 
 impl IntoDiagnosticArg for PathBuf {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Owned(self.display().to_string()))
     }
 }
 
 impl IntoDiagnosticArg for PanicStrategy {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Owned(self.desc().to_string()))
     }
 }
 
 impl IntoDiagnosticArg for hir::ConstContext {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Borrowed(match self {
             hir::ConstContext::ConstFn => "const_fn",
             hir::ConstContext::Static(_) => "static",
@@ -175,57 +175,57 @@ impl IntoDiagnosticArg for hir::ConstContext {
 }
 
 impl IntoDiagnosticArg for ast::Expr {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Owned(pprust::expr_to_string(&self)))
     }
 }
 
 impl IntoDiagnosticArg for ast::Path {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Owned(pprust::path_to_string(&self)))
     }
 }
 
 impl IntoDiagnosticArg for ast::token::Token {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(pprust::token_to_string(&self))
     }
 }
 
 impl IntoDiagnosticArg for ast::token::TokenKind {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(pprust::token_kind_to_string(&self))
     }
 }
 
 impl IntoDiagnosticArg for type_ir::FloatTy {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Borrowed(self.name_str()))
     }
 }
 
 impl IntoDiagnosticArg for std::ffi::CString {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Owned(self.to_string_lossy().into_owned()))
     }
 }
 
 impl IntoDiagnosticArg for rustc_data_structures::small_c_str::SmallCStr {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Owned(self.to_string_lossy().into_owned()))
     }
 }
 
 impl IntoDiagnosticArg for ast::Visibility {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         let s = pprust::vis_to_string(&self);
         let s = s.trim_end().to_string();
         DiagnosticArgValue::Str(Cow::Owned(s))
     }
 }
 
 impl IntoDiagnosticArg for rustc_lint_defs::Level {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Borrowed(self.to_cmd_flag()))
     }
 }
@@ -240,15 +240,15 @@ impl From<Vec<Symbol>> for DiagnosticSymbolList {
 }
 
 impl IntoDiagnosticArg for DiagnosticSymbolList {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::StrListSepByAnd(
             self.0.into_iter().map(|sym| Cow::Owned(format!("`{sym}`"))).collect(),
         )
     }
 }
 
 impl<Id> IntoDiagnosticArg for hir::def::Res<Id> {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Borrowed(self.descr()))
     }
 }
@@ -334,13 +334,13 @@ pub struct DelayedAtWithoutNewline {
 }
 
 impl IntoDiagnosticArg for DiagnosticLocation {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::from(self.to_string()))
     }
 }
 
 impl IntoDiagnosticArg for Backtrace {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::from(self.to_string()))
     }
 }
@@ -353,7 +353,7 @@ pub struct InvalidFlushedDelayedDiagnosticLevel {
     pub level: Level,
 }
 impl IntoDiagnosticArg for Level {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::from(self.to_string()))
     }
 }
@@ -368,7 +368,7 @@ pub struct IndicateAnonymousLifetime {
 }
 
 impl IntoDiagnosticArg for type_ir::ClosureKind {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         DiagnosticArgValue::Str(self.as_str().into())
     }
 }