3 files changed, 52 insertions, 32 deletions
diff --git a/compiler/rustc_errors/src/diagnostic.rs b/compiler/rustc_errors/src/diagnostic.rs
index a52e95e92d5..31e410aaaf0 100644
--- a/compiler/rustc_errors/src/diagnostic.rs
+++ b/compiler/rustc_errors/src/diagnostic.rs
@@ -1,8 +1,10 @@
 use crate::snippet::Style;
 use crate::{
-    CodeSuggestion, DiagnosticMessage, EmissionGuarantee, Level, LintDiagnosticBuilder, MultiSpan,
+    CodeSuggestion, DiagnosticBuilder, DiagnosticMessage, EmissionGuarantee, Level, MultiSpan,
     SubdiagnosticMessage, Substitution, SubstitutionPart, SuggestionStyle,
 };
+use rustc_ast as ast;
+use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_error_messages::FluentValue;
 use rustc_hir as hir;
@@ -175,6 +177,24 @@ impl IntoDiagnosticArg for hir::ConstContext {
     }
 }
 
+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))
+    }
+}
+
 /// Trait implemented by error types. This should not be implemented manually. Instead, use
 /// `#[derive(Subdiagnostic)]` -- see [rustc_macros::Subdiagnostic].
 #[cfg_attr(bootstrap, rustc_diagnostic_item = "AddSubdiagnostic")]
@@ -189,7 +209,12 @@ pub trait AddToDiagnostic {
 #[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]
diff --git a/compiler/rustc_errors/src/diagnostic_builder.rs b/compiler/rustc_errors/src/diagnostic_builder.rs
index b4ba65ca96d..bbe6435be59 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;
@@ -23,6 +24,18 @@ pub trait IntoDiagnostic<'a, T: EmissionGuarantee = ErrorGuaranteed> {
     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
@@ -629,27 +642,3 @@ 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/lib.rs b/compiler/rustc_errors/src/lib.rs
index 68971cebc35..7c312da6279 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,
 };
@@ -63,13 +62,14 @@ 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)]
@@ -374,7 +374,7 @@ pub use diagnostic::{
     AddToDiagnostic, DecorateLint, Diagnostic, DiagnosticArg, DiagnosticArgFromDisplay,
     DiagnosticArgValue, DiagnosticId, DiagnosticStyledString, IntoDiagnosticArg, SubDiagnostic,
 };
-pub use diagnostic_builder::{DiagnosticBuilder, EmissionGuarantee, LintDiagnosticBuilder};
+pub use diagnostic_builder::{DiagnosticBuilder, EmissionGuarantee};
 use std::backtrace::Backtrace;
 
 /// A handler deals with errors and other compiler output.
@@ -1134,6 +1134,12 @@ 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 {