Merging upstream version 1.66.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

9 files changed, 508 insertions, 205 deletions

diff --git a/compiler/rustc_errors/Cargo.toml b/compiler/rustc_errors/Cargo.toml
index c36ca11fa..7803a0792 100644
--- a/compiler/rustc_errors/Cargo.toml
+++ b/compiler/rustc_errors/Cargo.toml
@@ -4,10 +4,11 @@ version = "0.0.0"
 edition = "2021"
 
 [lib]
-doctest = false
 
 [dependencies]
 tracing = "0.1"
+rustc_ast = { path = "../rustc_ast" }
+rustc_ast_pretty = { path = "../rustc_ast_pretty" }
 rustc_error_messages = { path = "../rustc_error_messages" }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_span = { path = "../rustc_span" }
diff --git a/compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs b/compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs
index b32fc3c71..f14b8ee32 100644
--- a/compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs
+++ b/compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs
@@ -7,7 +7,7 @@
 
 use crate::emitter::FileWithAnnotatedLines;
 use crate::snippet::Line;
-use crate::translation::Translate;
+use crate::translation::{to_fluent_args, Translate};
 use crate::{
     CodeSuggestion, Diagnostic, DiagnosticId, DiagnosticMessage, Emitter, FluentBundle,
     LazyFallbackBundle, Level, MultiSpan, Style, SubDiagnostic,
@@ -46,7 +46,7 @@ impl Translate for AnnotateSnippetEmitterWriter {
 impl Emitter for AnnotateSnippetEmitterWriter {
     /// The entry point for the diagnostics generation
     fn emit_diagnostic(&mut self, diag: &Diagnostic) {
-        let fluent_args = self.to_fluent_args(diag.args());
+        let fluent_args = to_fluent_args(diag.args());
 
         let mut children = diag.children.clone();
         let (mut primary_span, suggestions) = self.primary_span_formatted(&diag, &fluent_args);
diff --git a/compiler/rustc_errors/src/diagnostic.rs b/compiler/rustc_errors/src/diagnostic.rs
index a774b52c8..23f29a24f 100644
--- a/compiler/rustc_errors/src/diagnostic.rs
+++ b/compiler/rustc_errors/src/diagnostic.rs
@@ -1,21 +1,17 @@
 use crate::snippet::Style;
 use crate::{
-    CodeSuggestion, DiagnosticMessage, EmissionGuarantee, Level, LintDiagnosticBuilder, MultiSpan,
+    CodeSuggestion, DiagnosticBuilder, DiagnosticMessage, EmissionGuarantee, Level, MultiSpan,
     SubdiagnosticMessage, Substitution, SubstitutionPart, SuggestionStyle,
 };
 use rustc_data_structures::fx::FxHashMap;
 use rustc_error_messages::FluentValue;
-use rustc_hir as hir;
 use rustc_lint_defs::{Applicability, LintExpectationId};
 use rustc_span::edition::LATEST_STABLE_EDITION;
-use rustc_span::symbol::{Ident, MacroRulesNormalizedIdent, Symbol};
-use rustc_span::{edition::Edition, Span, DUMMY_SP};
-use rustc_target::spec::{PanicStrategy, SplitDebuginfo, StackProtector, TargetTriple};
+use rustc_span::symbol::Symbol;
+use rustc_span::{Span, DUMMY_SP};
 use std::borrow::Cow;
 use std::fmt;
 use std::hash::{Hash, Hasher};
-use std::num::ParseIntError;
-use std::path::{Path, PathBuf};
 
 /// Error type for `Diagnostic`'s `suggestions` field, indicating that
 /// `.disable_suggestions()` was called on the `Diagnostic`.
@@ -25,7 +21,11 @@ pub struct SuggestionsDisabled;
 /// Simplified version of `FluentArg` that can implement `Encodable` and `Decodable`. Collection of
 /// `DiagnosticArg` are converted to `FluentArgs` (consuming the collection) at the start of
 /// diagnostic emission.
-pub type DiagnosticArg<'source> = (Cow<'source, str>, DiagnosticArgValue<'source>);
+pub type DiagnosticArg<'iter, 'source> =
+    (&'iter DiagnosticArgName<'source>, &'iter DiagnosticArgValue<'source>);
+
+/// 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.
@@ -35,7 +35,7 @@ pub enum DiagnosticArgValue<'source> {
     Number(usize),
 }
 
-/// Converts a value of a type into a `DiagnosticArg` (typically a field of a `SessionDiagnostic`
+/// 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.
@@ -43,119 +43,6 @@ pub trait IntoDiagnosticArg {
     fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static>;
 }
 
-pub struct DiagnosticArgFromDisplay<'a>(pub &'a dyn fmt::Display);
-
-impl IntoDiagnosticArg for DiagnosticArgFromDisplay<'_> {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        self.0.to_string().into_diagnostic_arg()
-    }
-}
-
-impl<'a> From<&'a dyn fmt::Display> for DiagnosticArgFromDisplay<'a> {
-    fn from(t: &'a dyn fmt::Display) -> Self {
-        DiagnosticArgFromDisplay(t)
-    }
-}
-
-impl<'a, T: fmt::Display> From<&'a T> for DiagnosticArgFromDisplay<'a> {
-    fn from(t: &'a T) -> Self {
-        DiagnosticArgFromDisplay(t)
-    }
-}
-
-macro_rules! into_diagnostic_arg_using_display {
-    ($( $ty:ty ),+ $(,)?) => {
-        $(
-            impl IntoDiagnosticArg for $ty {
-                fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-                    self.to_string().into_diagnostic_arg()
-                }
-            }
-        )+
-    }
-}
-
-into_diagnostic_arg_using_display!(
-    i8,
-    u8,
-    i16,
-    u16,
-    i32,
-    u32,
-    i64,
-    u64,
-    i128,
-    u128,
-    std::io::Error,
-    std::num::NonZeroU32,
-    hir::Target,
-    Edition,
-    Ident,
-    MacroRulesNormalizedIdent,
-    ParseIntError,
-    StackProtector,
-    &TargetTriple,
-    SplitDebuginfo
-);
-
-impl IntoDiagnosticArg for bool {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        if self {
-            DiagnosticArgValue::Str(Cow::Borrowed("true"))
-        } else {
-            DiagnosticArgValue::Str(Cow::Borrowed("false"))
-        }
-    }
-}
-
-impl IntoDiagnosticArg for char {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(format!("{:?}", self)))
-    }
-}
-
-impl IntoDiagnosticArg for Symbol {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        self.to_ident_string().into_diagnostic_arg()
-    }
-}
-
-impl<'a> IntoDiagnosticArg for &'a str {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        self.to_string().into_diagnostic_arg()
-    }
-}
-
-impl IntoDiagnosticArg for String {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(self))
-    }
-}
-
-impl<'a> IntoDiagnosticArg for &'a Path {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(self.display().to_string()))
-    }
-}
-
-impl IntoDiagnosticArg for PathBuf {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(self.display().to_string()))
-    }
-}
-
-impl IntoDiagnosticArg for usize {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Number(self)
-    }
-}
-
-impl IntoDiagnosticArg for PanicStrategy {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(self.desc().to_string()))
-    }
-}
-
 impl<'source> Into<FluentValue<'source>> for DiagnosticArgValue<'source> {
     fn into(self) -> FluentValue<'source> {
         match self {
@@ -165,22 +52,24 @@ impl<'source> Into<FluentValue<'source>> for DiagnosticArgValue<'source> {
     }
 }
 
-impl IntoDiagnosticArg for hir::ConstContext {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Borrowed(match self {
-            hir::ConstContext::ConstFn => "constant function",
-            hir::ConstContext::Static(_) => "static",
-            hir::ConstContext::Const => "constant",
-        }))
-    }
-}
-
 /// Trait implemented by error types. This should not be implemented manually. Instead, use
-/// `#[derive(SessionSubdiagnostic)]` -- see [rustc_macros::SessionSubdiagnostic].
-#[rustc_diagnostic_item = "AddSubdiagnostic"]
-pub trait AddSubdiagnostic {
+/// `#[derive(Subdiagnostic)]` -- see [rustc_macros::Subdiagnostic].
+#[cfg_attr(bootstrap, rustc_diagnostic_item = "AddSubdiagnostic")]
+#[cfg_attr(not(bootstrap), rustc_diagnostic_item = "AddToDiagnostic")]
+pub trait AddToDiagnostic
+where
+    Self: Sized,
+{
     /// Add a subdiagnostic to an existing diagnostic.
-    fn add_to_diagnostic(self, diag: &mut Diagnostic);
+    fn add_to_diagnostic(self, diag: &mut Diagnostic) {
+        self.add_to_diagnostic_with(diag, |_, m| m);
+    }
+
+    /// Add a subdiagnostic to an existing diagnostic where `f` is invoked on every message used
+    /// (to optionally perform eager translation).
+    fn add_to_diagnostic_with<F>(self, diag: &mut Diagnostic, f: F)
+    where
+        F: Fn(&mut Diagnostic, SubdiagnosticMessage) -> SubdiagnosticMessage;
 }
 
 /// Trait implemented by lint types. This should not be implemented manually. Instead, use
@@ -188,7 +77,12 @@ pub trait AddSubdiagnostic {
 #[rustc_diagnostic_item = "DecorateLint"]
 pub trait DecorateLint<'a, G: EmissionGuarantee> {
     /// Decorate and emit a lint.
-    fn decorate_lint(self, diag: LintDiagnosticBuilder<'a, G>);
+    fn decorate_lint<'b>(
+        self,
+        diag: &'b mut DiagnosticBuilder<'a, G>,
+    ) -> &'b mut DiagnosticBuilder<'a, G>;
+
+    fn msg(&self) -> DiagnosticMessage;
 }
 
 #[must_use]
@@ -203,7 +97,7 @@ pub struct Diagnostic {
     pub span: MultiSpan,
     pub children: Vec<SubDiagnostic>,
     pub suggestions: Result<Vec<CodeSuggestion>, SuggestionsDisabled>,
-    args: Vec<DiagnosticArg<'static>>,
+    args: FxHashMap<DiagnosticArgName<'static>, DiagnosticArgValue<'static>>,
 
     /// 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
@@ -295,7 +189,7 @@ impl Diagnostic {
             span: MultiSpan::new(),
             children: vec![],
             suggestions: Ok(vec![]),
-            args: vec![],
+            args: Default::default(),
             sort_span: DUMMY_SP,
             is_lint: false,
         }
@@ -338,9 +232,10 @@ impl Diagnostic {
             // The lint index inside the attribute is manually transferred here.
             let lint_index = expectation_id.get_lint_index();
             expectation_id.set_lint_index(None);
-            let mut stable_id = *unstable_to_stable
+            let mut stable_id = unstable_to_stable
                 .get(&expectation_id)
-                .expect("each unstable `LintExpectationId` must have a matching stable id");
+                .expect("each unstable `LintExpectationId` must have a matching stable id")
+                .normalize();
 
             stable_id.set_lint_index(lint_index);
             *expectation_id = stable_id;
@@ -672,6 +567,11 @@ impl Diagnostic {
         style: SuggestionStyle,
     ) -> &mut Self {
         assert!(!suggestion.is_empty());
+        debug_assert!(
+            !(suggestion.iter().any(|(sp, text)| sp.is_empty() && text.is_empty())),
+            "Span must not be empty and have no suggestion"
+        );
+
         self.push_suggestion(CodeSuggestion {
             substitutions: vec![Substitution {
                 parts: suggestion
@@ -749,6 +649,10 @@ impl Diagnostic {
         applicability: Applicability,
         style: SuggestionStyle,
     ) -> &mut Self {
+        debug_assert!(
+            !(sp.is_empty() && suggestion.to_string().is_empty()),
+            "Span must not be empty and have no suggestion"
+        );
         self.push_suggestion(CodeSuggestion {
             substitutions: vec![Substitution {
                 parts: vec![SubstitutionPart { snippet: suggestion.to_string(), span: sp }],
@@ -787,8 +691,32 @@ impl Diagnostic {
         suggestions: impl Iterator<Item = String>,
         applicability: Applicability,
     ) -> &mut Self {
+        self.span_suggestions_with_style(
+            sp,
+            msg,
+            suggestions,
+            applicability,
+            SuggestionStyle::ShowCode,
+        )
+    }
+
+    /// [`Diagnostic::span_suggestions()`] but you can set the [`SuggestionStyle`].
+    pub fn span_suggestions_with_style(
+        &mut self,
+        sp: Span,
+        msg: impl Into<SubdiagnosticMessage>,
+        suggestions: impl Iterator<Item = String>,
+        applicability: Applicability,
+        style: SuggestionStyle,
+    ) -> &mut Self {
         let mut suggestions: Vec<_> = suggestions.collect();
         suggestions.sort();
+
+        debug_assert!(
+            !(sp.is_empty() && suggestions.iter().any(|suggestion| suggestion.is_empty())),
+            "Span must not be empty and have no suggestion"
+        );
+
         let substitutions = suggestions
             .into_iter()
             .map(|snippet| Substitution { parts: vec![SubstitutionPart { snippet, span: sp }] })
@@ -796,22 +724,33 @@ impl Diagnostic {
         self.push_suggestion(CodeSuggestion {
             substitutions,
             msg: self.subdiagnostic_message_to_diagnostic_message(msg),
-            style: SuggestionStyle::ShowCode,
+            style,
             applicability,
         });
         self
     }
 
-    /// Prints out a message with multiple suggested edits of the code.
-    /// See also [`Diagnostic::span_suggestion()`].
+    /// Prints out a message with multiple suggested edits of the code, where each edit consists of
+    /// multiple parts.
+    /// See also [`Diagnostic::multipart_suggestion()`].
     pub fn multipart_suggestions(
         &mut self,
         msg: impl Into<SubdiagnosticMessage>,
         suggestions: impl Iterator<Item = Vec<(Span, String)>>,
         applicability: Applicability,
     ) -> &mut Self {
+        let suggestions: Vec<_> = suggestions.collect();
+        debug_assert!(
+            !(suggestions
+                .iter()
+                .flat_map(|suggs| suggs)
+                .any(|(sp, suggestion)| sp.is_empty() && suggestion.is_empty())),
+            "Span must not be empty and have no suggestion"
+        );
+
         self.push_suggestion(CodeSuggestion {
             substitutions: suggestions
+                .into_iter()
                 .map(|sugg| Substitution {
                     parts: sugg
                         .into_iter()
@@ -825,6 +764,7 @@ impl Diagnostic {
         });
         self
     }
+
     /// Prints out a message with a suggested edit of the code. If the suggestion is presented
     /// inline, it will only show the message and not the suggestion.
     ///
@@ -890,13 +830,30 @@ impl Diagnostic {
         self
     }
 
-    /// Add a subdiagnostic from a type that implements `SessionSubdiagnostic` - see
-    /// [rustc_macros::SessionSubdiagnostic].
-    pub fn subdiagnostic(&mut self, subdiagnostic: impl AddSubdiagnostic) -> &mut Self {
+    /// Add a subdiagnostic from a type that implements `Subdiagnostic` (see
+    /// [rustc_macros::Subdiagnostic]).
+    pub fn subdiagnostic(&mut self, subdiagnostic: impl AddToDiagnostic) -> &mut Self {
         subdiagnostic.add_to_diagnostic(self);
         self
     }
 
+    /// Add a subdiagnostic from a type that implements `Subdiagnostic` (see
+    /// [rustc_macros::Subdiagnostic]). Performs eager translation of any translatable messages
+    /// used in the subdiagnostic, so suitable for use with repeated messages (i.e. re-use of
+    /// interpolated variables).
+    pub fn eager_subdiagnostic(
+        &mut self,
+        handler: &crate::Handler,
+        subdiagnostic: impl AddToDiagnostic,
+    ) -> &mut Self {
+        subdiagnostic.add_to_diagnostic_with(self, |diag, msg| {
+            let args = diag.args();
+            let msg = diag.subdiagnostic_message_to_diagnostic_message(msg);
+            handler.eagerly_translate(msg, args)
+        });
+        self
+    }
+
     pub fn set_span<S: Into<MultiSpan>>(&mut self, sp: S) -> &mut Self {
         self.span = sp.into();
         if let Some(span) = self.span.primary_span() {
@@ -929,8 +886,11 @@ impl Diagnostic {
         self
     }
 
-    pub fn args(&self) -> &[DiagnosticArg<'static>] {
-        &self.args
+    // Exact iteration order of diagnostic arguments shouldn't make a difference to output because
+    // they're only used in interpolation.
+    #[allow(rustc::potential_query_instability)]
+    pub fn args<'a>(&'a self) -> impl Iterator<Item = DiagnosticArg<'a, 'static>> {
+        self.args.iter()
     }
 
     pub fn set_arg(
@@ -938,7 +898,7 @@ impl Diagnostic {
         name: impl Into<Cow<'static, str>>,
         arg: impl IntoDiagnosticArg,
     ) -> &mut Self {
-        self.args.push((name.into(), arg.into_diagnostic_arg()));
+        self.args.insert(name.into(), arg.into_diagnostic_arg());
         self
     }
 
@@ -949,7 +909,7 @@ impl Diagnostic {
     /// Helper function that takes a `SubdiagnosticMessage` and returns a `DiagnosticMessage` by
     /// combining it with the primary message of the diagnostic (if translatable, otherwise it just
     /// passes the user's string along).
-    fn subdiagnostic_message_to_diagnostic_message(
+    pub(crate) fn subdiagnostic_message_to_diagnostic_message(
         &self,
         attr: impl Into<SubdiagnosticMessage>,
     ) -> DiagnosticMessage {
diff --git a/compiler/rustc_errors/src/diagnostic_builder.rs b/compiler/rustc_errors/src/diagnostic_builder.rs
index 7e29dc207..9b41234dc 100644
--- a/compiler/rustc_errors/src/diagnostic_builder.rs
+++ b/compiler/rustc_errors/src/diagnostic_builder.rs
@@ -5,6 +5,7 @@ use crate::{
 };
 use crate::{Handler, Level, MultiSpan, StashKey};
 use rustc_lint_defs::Applicability;
+use rustc_span::source_map::Spanned;
 
 use rustc_span::Span;
 use std::borrow::Cow;
@@ -13,6 +14,28 @@ use std::marker::PhantomData;
 use std::ops::{Deref, DerefMut};
 use std::thread::panicking;
 
+/// Trait implemented by error types. This should not be implemented manually. Instead, use
+/// `#[derive(Diagnostic)]` -- see [rustc_macros::Diagnostic].
+#[cfg_attr(bootstrap, rustc_diagnostic_item = "SessionDiagnostic")]
+#[cfg_attr(not(bootstrap), rustc_diagnostic_item = "IntoDiagnostic")]
+pub trait IntoDiagnostic<'a, T: EmissionGuarantee = ErrorGuaranteed> {
+    /// Write out as a diagnostic out of `Handler`.
+    #[must_use]
+    fn into_diagnostic(self, handler: &'a Handler) -> DiagnosticBuilder<'a, T>;
+}
+
+impl<'a, T, E> IntoDiagnostic<'a, E> for Spanned<T>
+where
+    T: IntoDiagnostic<'a, E>,
+    E: EmissionGuarantee,
+{
+    fn into_diagnostic(self, handler: &'a Handler) -> DiagnosticBuilder<'a, E> {
+        let mut diag = self.node.into_diagnostic(handler);
+        diag.set_span(self.span);
+        diag
+    }
+}
+
 /// Used for emitting structured error messages and other diagnostic information.
 ///
 /// If there is some state in a downstream crate you would like to
@@ -232,6 +255,56 @@ impl EmissionGuarantee for () {
     }
 }
 
+/// Marker type which enables implementation of `create_note` and `emit_note` functions for
+/// note-without-error struct diagnostics.
+#[derive(Copy, Clone)]
+pub struct Noted;
+
+impl<'a> DiagnosticBuilder<'a, Noted> {
+    /// Convenience function for internal use, clients should use one of the
+    /// `struct_*` methods on [`Handler`].
+    pub(crate) fn new_note(handler: &'a Handler, message: impl Into<DiagnosticMessage>) -> Self {
+        let diagnostic = Diagnostic::new_with_code(Level::Note, None, message);
+        Self::new_diagnostic_note(handler, diagnostic)
+    }
+
+    /// Creates a new `DiagnosticBuilder` with an already constructed
+    /// diagnostic.
+    pub(crate) fn new_diagnostic_note(handler: &'a Handler, diagnostic: Diagnostic) -> Self {
+        debug!("Created new diagnostic");
+        Self {
+            inner: DiagnosticBuilderInner {
+                state: DiagnosticBuilderState::Emittable(handler),
+                diagnostic: Box::new(diagnostic),
+            },
+            _marker: PhantomData,
+        }
+    }
+}
+
+impl EmissionGuarantee for Noted {
+    fn diagnostic_builder_emit_producing_guarantee(db: &mut DiagnosticBuilder<'_, Self>) -> Self {
+        match db.inner.state {
+            // First `.emit()` call, the `&Handler` is still available.
+            DiagnosticBuilderState::Emittable(handler) => {
+                db.inner.state = DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation;
+                handler.emit_diagnostic(&mut db.inner.diagnostic);
+            }
+            // `.emit()` was previously called, disallowed from repeating it.
+            DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation => {}
+        }
+
+        Noted
+    }
+
+    fn make_diagnostic_builder(
+        handler: &Handler,
+        msg: impl Into<DiagnosticMessage>,
+    ) -> DiagnosticBuilder<'_, Self> {
+        DiagnosticBuilder::new_note(handler, msg)
+    }
+}
+
 impl<'a> DiagnosticBuilder<'a, !> {
     /// Convenience function for internal use, clients should use one of the
     /// `struct_*` methods on [`Handler`].
@@ -570,7 +643,7 @@ impl<'a, G: EmissionGuarantee> DiagnosticBuilder<'a, G> {
 
     forward!(pub fn subdiagnostic(
         &mut self,
-        subdiagnostic: impl crate::AddSubdiagnostic
+        subdiagnostic: impl crate::AddToDiagnostic
     ) -> &mut Self);
 }
 
@@ -619,27 +692,3 @@ macro_rules! struct_span_err {
 macro_rules! error_code {
     ($code:ident) => {{ $crate::DiagnosticId::Error(stringify!($code).to_owned()) }};
 }
-
-/// Wrapper around a `DiagnosticBuilder` for creating lints.
-pub struct LintDiagnosticBuilder<'a, G: EmissionGuarantee>(DiagnosticBuilder<'a, G>);
-
-impl<'a, G: EmissionGuarantee> LintDiagnosticBuilder<'a, G> {
-    #[rustc_lint_diagnostics]
-    /// Return the inner `DiagnosticBuilder`, first setting the primary message to `msg`.
-    pub fn build(mut self, msg: impl Into<DiagnosticMessage>) -> DiagnosticBuilder<'a, G> {
-        self.0.set_primary_message(msg);
-        self.0.set_is_lint();
-        self.0
-    }
-
-    /// Create a `LintDiagnosticBuilder` from some existing `DiagnosticBuilder`.
-    pub fn new(err: DiagnosticBuilder<'a, G>) -> LintDiagnosticBuilder<'a, G> {
-        LintDiagnosticBuilder(err)
-    }
-}
-
-impl<'a> LintDiagnosticBuilder<'a, ErrorGuaranteed> {
-    pub fn forget_guarantee(self) -> LintDiagnosticBuilder<'a, ()> {
-        LintDiagnosticBuilder(self.0.forget_guarantee())
-    }
-}
diff --git a/compiler/rustc_errors/src/diagnostic_impls.rs b/compiler/rustc_errors/src/diagnostic_impls.rs
new file mode 100644
index 000000000..7640b2919
--- /dev/null
+++ b/compiler/rustc_errors/src/diagnostic_impls.rs
@@ -0,0 +1,222 @@
+use crate::{
+    fluent, DiagnosticArgValue, DiagnosticBuilder, Handler, IntoDiagnostic, IntoDiagnosticArg,
+};
+use rustc_ast as ast;
+use rustc_ast_pretty::pprust;
+use rustc_hir as hir;
+use rustc_lint_defs::Level;
+use rustc_span::edition::Edition;
+use rustc_span::symbol::{Ident, MacroRulesNormalizedIdent, Symbol};
+use rustc_target::abi::TargetDataLayoutErrors;
+use rustc_target::spec::{PanicStrategy, SplitDebuginfo, StackProtector, TargetTriple};
+use std::borrow::Cow;
+use std::fmt;
+use std::num::ParseIntError;
+use std::path::{Path, PathBuf};
+
+pub struct DiagnosticArgFromDisplay<'a>(pub &'a dyn fmt::Display);
+
+impl IntoDiagnosticArg for DiagnosticArgFromDisplay<'_> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        self.0.to_string().into_diagnostic_arg()
+    }
+}
+
+impl<'a> From<&'a dyn fmt::Display> for DiagnosticArgFromDisplay<'a> {
+    fn from(t: &'a dyn fmt::Display) -> Self {
+        DiagnosticArgFromDisplay(t)
+    }
+}
+
+impl<'a, T: fmt::Display> From<&'a T> for DiagnosticArgFromDisplay<'a> {
+    fn from(t: &'a T) -> Self {
+        DiagnosticArgFromDisplay(t)
+    }
+}
+
+macro_rules! into_diagnostic_arg_using_display {
+    ($( $ty:ty ),+ $(,)?) => {
+        $(
+            impl IntoDiagnosticArg for $ty {
+                fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+                    self.to_string().into_diagnostic_arg()
+                }
+            }
+        )+
+    }
+}
+
+into_diagnostic_arg_using_display!(
+    i8,
+    u8,
+    i16,
+    u16,
+    i32,
+    u32,
+    i64,
+    u64,
+    i128,
+    u128,
+    std::io::Error,
+    std::num::NonZeroU32,
+    hir::Target,
+    Edition,
+    Ident,
+    MacroRulesNormalizedIdent,
+    ParseIntError,
+    StackProtector,
+    &TargetTriple,
+    SplitDebuginfo
+);
+
+impl IntoDiagnosticArg for bool {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        if self {
+            DiagnosticArgValue::Str(Cow::Borrowed("true"))
+        } else {
+            DiagnosticArgValue::Str(Cow::Borrowed("false"))
+        }
+    }
+}
+
+impl IntoDiagnosticArg for char {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(format!("{:?}", self)))
+    }
+}
+
+impl IntoDiagnosticArg for Symbol {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        self.to_ident_string().into_diagnostic_arg()
+    }
+}
+
+impl<'a> IntoDiagnosticArg for &'a str {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        self.to_string().into_diagnostic_arg()
+    }
+}
+
+impl IntoDiagnosticArg for String {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self))
+    }
+}
+
+impl<'a> IntoDiagnosticArg for &'a Path {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.display().to_string()))
+    }
+}
+
+impl IntoDiagnosticArg for PathBuf {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.display().to_string()))
+    }
+}
+
+impl IntoDiagnosticArg for usize {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Number(self)
+    }
+}
+
+impl IntoDiagnosticArg for PanicStrategy {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.desc().to_string()))
+    }
+}
+
+impl IntoDiagnosticArg for hir::ConstContext {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Borrowed(match self {
+            hir::ConstContext::ConstFn => "constant function",
+            hir::ConstContext::Static(_) => "static",
+            hir::ConstContext::Const => "constant",
+        }))
+    }
+}
+
+impl IntoDiagnosticArg for ast::Path {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(pprust::path_to_string(&self)))
+    }
+}
+
+impl IntoDiagnosticArg for ast::token::Token {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(pprust::token_to_string(&self))
+    }
+}
+
+impl IntoDiagnosticArg for ast::token::TokenKind {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(pprust::token_kind_to_string(&self))
+    }
+}
+
+impl IntoDiagnosticArg for Level {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Borrowed(match self {
+            Level::Allow => "-A",
+            Level::Warn => "-W",
+            Level::ForceWarn(_) => "--force-warn",
+            Level::Deny => "-D",
+            Level::Forbid => "-F",
+            Level::Expect(_) => {
+                unreachable!("lints with the level of `expect` should not run this code");
+            }
+        }))
+    }
+}
+
+impl IntoDiagnostic<'_, !> for TargetDataLayoutErrors<'_> {
+    fn into_diagnostic(self, handler: &Handler) -> DiagnosticBuilder<'_, !> {
+        let mut diag;
+        match self {
+            TargetDataLayoutErrors::InvalidAddressSpace { addr_space, err, cause } => {
+                diag = handler.struct_fatal(fluent::errors_target_invalid_address_space);
+                diag.set_arg("addr_space", addr_space);
+                diag.set_arg("cause", cause);
+                diag.set_arg("err", err);
+                diag
+            }
+            TargetDataLayoutErrors::InvalidBits { kind, bit, cause, err } => {
+                diag = handler.struct_fatal(fluent::errors_target_invalid_bits);
+                diag.set_arg("kind", kind);
+                diag.set_arg("bit", bit);
+                diag.set_arg("cause", cause);
+                diag.set_arg("err", err);
+                diag
+            }
+            TargetDataLayoutErrors::MissingAlignment { cause } => {
+                diag = handler.struct_fatal(fluent::errors_target_missing_alignment);
+                diag.set_arg("cause", cause);
+                diag
+            }
+            TargetDataLayoutErrors::InvalidAlignment { cause, err } => {
+                diag = handler.struct_fatal(fluent::errors_target_invalid_alignment);
+                diag.set_arg("cause", cause);
+                diag.set_arg("err", err);
+                diag
+            }
+            TargetDataLayoutErrors::InconsistentTargetArchitecture { dl, target } => {
+                diag = handler.struct_fatal(fluent::errors_target_inconsistent_architecture);
+                diag.set_arg("dl", dl);
+                diag.set_arg("target", target);
+                diag
+            }
+            TargetDataLayoutErrors::InconsistentTargetPointerWidth { pointer_size, target } => {
+                diag = handler.struct_fatal(fluent::errors_target_inconsistent_pointer_width);
+                diag.set_arg("pointer_size", pointer_size);
+                diag.set_arg("target", target);
+                diag
+            }
+            TargetDataLayoutErrors::InvalidBitsSize { err } => {
+                diag = handler.struct_fatal(fluent::errors_target_invalid_bits_size);
+                diag.set_arg("err", err);
+                diag
+            }
+        }
+    }
+}
diff --git a/compiler/rustc_errors/src/emitter.rs b/compiler/rustc_errors/src/emitter.rs
index 66fbb8f12..cd6413bc3 100644
--- a/compiler/rustc_errors/src/emitter.rs
+++ b/compiler/rustc_errors/src/emitter.rs
@@ -14,7 +14,7 @@ use rustc_span::{FileLines, SourceFile, Span};
 
 use crate::snippet::{Annotation, AnnotationType, Line, MultilineAnnotation, Style, StyledString};
 use crate::styled_buffer::StyledBuffer;
-use crate::translation::Translate;
+use crate::translation::{to_fluent_args, Translate};
 use crate::{
     CodeSuggestion, Diagnostic, DiagnosticId, DiagnosticMessage, FluentBundle, Handler,
     LazyFallbackBundle, Level, MultiSpan, SubDiagnostic, SubstitutionHighlight, SuggestionStyle,
@@ -535,7 +535,7 @@ impl Emitter for EmitterWriter {
     }
 
     fn emit_diagnostic(&mut self, diag: &Diagnostic) {
-        let fluent_args = self.to_fluent_args(diag.args());
+        let fluent_args = to_fluent_args(diag.args());
 
         let mut children = diag.children.clone();
         let (mut primary_span, suggestions) = self.primary_span_formatted(&diag, &fluent_args);
diff --git a/compiler/rustc_errors/src/json.rs b/compiler/rustc_errors/src/json.rs
index 1680c6acc..4cc7be47f 100644
--- a/compiler/rustc_errors/src/json.rs
+++ b/compiler/rustc_errors/src/json.rs
@@ -13,7 +13,7 @@ use rustc_span::source_map::{FilePathMapping, SourceMap};
 
 use crate::emitter::{Emitter, HumanReadableErrorType};
 use crate::registry::Registry;
-use crate::translation::Translate;
+use crate::translation::{to_fluent_args, Translate};
 use crate::DiagnosticId;
 use crate::{
     CodeSuggestion, FluentBundle, LazyFallbackBundle, MultiSpan, SpanLabel, SubDiagnostic,
@@ -312,7 +312,7 @@ struct UnusedExterns<'a, 'b, 'c> {
 
 impl Diagnostic {
     fn from_errors_diagnostic(diag: &crate::Diagnostic, je: &JsonEmitter) -> Diagnostic {
-        let args = je.to_fluent_args(diag.args());
+        let args = to_fluent_args(diag.args());
         let sugg = diag.suggestions.iter().flatten().map(|sugg| {
             let translated_message = je.translate_message(&sugg.msg, &args);
             Diagnostic {
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index a7b01feeb..0963ea71f 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -7,7 +7,6 @@
 #![feature(if_let_guard)]
 #![feature(adt_const_params)]
 #![feature(let_chains)]
-#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(never_type)]
 #![feature(result_option_inspect)]
 #![feature(rustc_attrs)]
@@ -31,7 +30,7 @@ use rustc_data_structures::stable_hasher::StableHasher;
 use rustc_data_structures::sync::{self, Lock, Lrc};
 use rustc_data_structures::AtomicRef;
 pub use rustc_error_messages::{
-    fallback_fluent_bundle, fluent, fluent_bundle, DiagnosticMessage, FluentBundle,
+    fallback_fluent_bundle, fluent, fluent_bundle, DelayDm, DiagnosticMessage, FluentBundle,
     LanguageIdentifier, LazyFallbackBundle, MultiSpan, SpanLabel, SubdiagnosticMessage,
     DEFAULT_LOCALE_RESOURCES,
 };
@@ -52,6 +51,7 @@ use termcolor::{Color, ColorSpec};
 pub mod annotate_snippet_emitter_writer;
 mod diagnostic;
 mod diagnostic_builder;
+mod diagnostic_impls;
 pub mod emitter;
 pub mod json;
 mod lock;
@@ -60,15 +60,17 @@ mod snippet;
 mod styled_buffer;
 pub mod translation;
 
+pub use diagnostic_builder::IntoDiagnostic;
 pub use snippet::Style;
 
-pub type PResult<'a, T> = Result<T, DiagnosticBuilder<'a, ErrorGuaranteed>>;
+pub type PErr<'a> = DiagnosticBuilder<'a, ErrorGuaranteed>;
+pub type PResult<'a, T> = Result<T, PErr<'a>>;
 
 // `PResult` is used a lot. Make sure it doesn't unintentionally get bigger.
-// (See also the comment on `DiagnosticBuilder`'s `diagnostic` field.)
+// (See also the comment on `DiagnosticBuilderInner`'s `diagnostic` field.)
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
 rustc_data_structures::static_assert_size!(PResult<'_, ()>, 16);
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64", not(bootstrap)))]
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
 rustc_data_structures::static_assert_size!(PResult<'_, bool>, 16);
 
 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, Encodable, Decodable)]
@@ -370,10 +372,11 @@ impl fmt::Display for ExplicitBug {
 impl error::Error for ExplicitBug {}
 
 pub use diagnostic::{
-    AddSubdiagnostic, DecorateLint, Diagnostic, DiagnosticArg, DiagnosticArgFromDisplay,
-    DiagnosticArgValue, DiagnosticId, DiagnosticStyledString, IntoDiagnosticArg, SubDiagnostic,
+    AddToDiagnostic, DecorateLint, Diagnostic, DiagnosticArg, DiagnosticArgValue, DiagnosticId,
+    DiagnosticStyledString, IntoDiagnosticArg, SubDiagnostic,
 };
-pub use diagnostic_builder::{DiagnosticBuilder, EmissionGuarantee, LintDiagnosticBuilder};
+pub use diagnostic_builder::{DiagnosticBuilder, EmissionGuarantee, Noted};
+pub use diagnostic_impls::DiagnosticArgFromDisplay;
 use std::backtrace::Backtrace;
 
 /// A handler deals with errors and other compiler output.
@@ -410,7 +413,7 @@ struct HandlerInner {
     /// would be unnecessary repetition.
     taught_diagnostics: FxHashSet<DiagnosticId>,
 
-    /// Used to suggest rustc --explain <error code>
+    /// Used to suggest rustc --explain `<error code>`
     emitted_diagnostic_codes: FxIndexSet<DiagnosticId>,
 
     /// This set contains a hash of every diagnostic that has been emitted by
@@ -436,11 +439,11 @@ struct HandlerInner {
     /// have been converted.
     check_unstable_expect_diagnostics: bool,
 
-    /// Expected [`Diagnostic`]s store a [`LintExpectationId`] as part of
+    /// Expected [`Diagnostic`][diagnostic::Diagnostic]s store a [`LintExpectationId`] as part of
     /// the lint level. [`LintExpectationId`]s created early during the compilation
     /// (before `HirId`s have been defined) are not stable and can therefore not be
     /// stored on disk. This buffer stores these diagnostics until the ID has been
-    /// replaced by a stable [`LintExpectationId`]. The [`Diagnostic`]s are the
+    /// replaced by a stable [`LintExpectationId`]. The [`Diagnostic`][diagnostic::Diagnostic]s are the
     /// submitted for storage and added to the list of fulfilled expectations.
     unstable_expect_diagnostics: Vec<Diagnostic>,
 
@@ -459,6 +462,10 @@ pub enum StashKey {
     ItemNoType,
     UnderscoreForArrayLengths,
     EarlySyntaxWarning,
+    CallIntoMethod,
+    /// When an invalid lifetime e.g. `'2` should be reinterpreted
+    /// as a char literal in the parser
+    LifetimeIsChar,
 }
 
 fn default_track_diagnostic(_: &Diagnostic) {}
@@ -596,6 +603,17 @@ impl Handler {
         }
     }
 
+    /// Translate `message` eagerly with `args`.
+    pub fn eagerly_translate<'a>(
+        &self,
+        message: DiagnosticMessage,
+        args: impl Iterator<Item = DiagnosticArg<'a, 'static>>,
+    ) -> SubdiagnosticMessage {
+        let inner = self.inner.borrow();
+        let args = crate::translation::to_fluent_args(args);
+        SubdiagnosticMessage::Eager(inner.emitter.translate_message(&message, &args).to_string())
+    }
+
     // This is here to not allow mutation of flags;
     // as of this writing it's only used in tests in librustc_middle.
     pub fn can_emit_warnings(&self) -> bool {
@@ -1028,6 +1046,39 @@ impl Handler {
         self.inner.borrow_mut().emit_diagnostic(diagnostic)
     }
 
+    pub fn emit_err<'a>(&'a self, err: impl IntoDiagnostic<'a>) -> ErrorGuaranteed {
+        self.create_err(err).emit()
+    }
+
+    pub fn create_err<'a>(
+        &'a self,
+        err: impl IntoDiagnostic<'a>,
+    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+        err.into_diagnostic(self)
+    }
+
+    pub fn create_warning<'a>(
+        &'a self,
+        warning: impl IntoDiagnostic<'a, ()>,
+    ) -> DiagnosticBuilder<'a, ()> {
+        warning.into_diagnostic(self)
+    }
+
+    pub fn emit_warning<'a>(&'a self, warning: impl IntoDiagnostic<'a, ()>) {
+        self.create_warning(warning).emit()
+    }
+
+    pub fn create_fatal<'a>(
+        &'a self,
+        fatal: impl IntoDiagnostic<'a, !>,
+    ) -> DiagnosticBuilder<'a, !> {
+        fatal.into_diagnostic(self)
+    }
+
+    pub fn emit_fatal<'a>(&'a self, fatal: impl IntoDiagnostic<'a, !>) -> ! {
+        self.create_fatal(fatal).emit()
+    }
+
     fn emit_diag_at_span(
         &self,
         mut diag: Diagnostic,
@@ -1100,6 +1151,12 @@ impl Handler {
         );
         std::mem::take(&mut self.inner.borrow_mut().fulfilled_expectations)
     }
+
+    pub fn flush_delayed(&self) {
+        let mut inner = self.inner.lock();
+        let bugs = std::mem::replace(&mut inner.delayed_span_bugs, Vec::new());
+        inner.flush_delayed(bugs, "no errors encountered even though `delay_span_bug` issued");
+    }
 }
 
 impl HandlerInner {
@@ -1171,7 +1228,7 @@ impl HandlerInner {
 
         if let Some(expectation_id) = diagnostic.level.get_expectation_id() {
             self.suppressed_expected_diag = true;
-            self.fulfilled_expectations.insert(expectation_id);
+            self.fulfilled_expectations.insert(expectation_id.normalize());
         }
 
         if matches!(diagnostic.level, Warning(_))
diff --git a/compiler/rustc_errors/src/translation.rs b/compiler/rustc_errors/src/translation.rs
index 4f407badb..a7737b467 100644
--- a/compiler/rustc_errors/src/translation.rs
+++ b/compiler/rustc_errors/src/translation.rs
@@ -4,6 +4,27 @@ use rustc_data_structures::sync::Lrc;
 use rustc_error_messages::FluentArgs;
 use std::borrow::Cow;
 
+/// Convert diagnostic arguments (a rustc internal type that exists to implement
+/// `Encodable`/`Decodable`) into `FluentArgs` which is necessary to perform translation.
+///
+/// Typically performed once for each diagnostic at the start of `emit_diagnostic` and then
+/// passed around as a reference thereafter.
+pub fn to_fluent_args<'iter, 'arg: 'iter>(
+    iter: impl Iterator<Item = DiagnosticArg<'iter, 'arg>>,
+) -> FluentArgs<'arg> {
+    let mut args = if let Some(size) = iter.size_hint().1 {
+        FluentArgs::with_capacity(size)
+    } else {
+        FluentArgs::new()
+    };
+
+    for (k, v) in iter {
+        args.set(k.clone(), v.clone());
+    }
+
+    args
+}
+
 pub trait Translate {
     /// Return `FluentBundle` with localized diagnostics for the locale requested by the user. If no
     /// language was requested by the user then this will be `None` and `fallback_fluent_bundle`
@@ -15,15 +36,6 @@ pub trait Translate {
     /// unavailable for the requested locale.
     fn fallback_fluent_bundle(&self) -> &FluentBundle;
 
-    /// Convert diagnostic arguments (a rustc internal type that exists to implement
-    /// `Encodable`/`Decodable`) into `FluentArgs` which is necessary to perform translation.
-    ///
-    /// Typically performed once for each diagnostic at the start of `emit_diagnostic` and then
-    /// passed around as a reference thereafter.
-    fn to_fluent_args<'arg>(&self, args: &[DiagnosticArg<'arg>]) -> FluentArgs<'arg> {
-        FromIterator::from_iter(args.iter().cloned())
-    }
-
     /// Convert `DiagnosticMessage`s to a string, performing translation if necessary.
     fn translate_messages(
         &self,
@@ -43,7 +55,9 @@ pub trait Translate {
     ) -> Cow<'_, str> {
         trace!(?message, ?args);
         let (identifier, attr) = match message {
-            DiagnosticMessage::Str(msg) => return Cow::Borrowed(&msg),
+            DiagnosticMessage::Str(msg) | DiagnosticMessage::Eager(msg) => {
+                return Cow::Borrowed(&msg);
+            }
             DiagnosticMessage::FluentIdentifier(identifier, attr) => (identifier, attr),
         };