From cea683c08f775f980e5e8de408ea3b47235329c7 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Mon, 18 Dec 2023 14:00:17 +1100
Subject: Use `.into_diagnostic()` less.

This commit replaces this pattern:
```
err.into_diagnostic(dcx)
```
with this pattern:
```
dcx.create_err(err)
```
in a lot of places.

It's a little shorter, makes the error level explicit, avoids some
`IntoDiagnostic` imports, and is a necessary prerequisite for the next
commit which will add a `level` arg to `into_diagnostic`.

This requires adding `track_caller` on `create_err` to avoid mucking up
the output of `tests/ui/track-diagnostics/track4.rs`. It probably should
have been there already.
---
 compiler/rustc_parse/src/parser/expr.rs | 66 +++++++++++++++++----------------
 1 file changed, 34 insertions(+), 32 deletions(-)

(limited to 'compiler/rustc_parse/src/parser/expr.rs')

diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index cd3e8b92f2f..a21a1533848 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -26,8 +26,8 @@ use rustc_ast::{ClosureBinder, MetaItemLit, StmtKind};
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_errors::{
-    AddToDiagnostic, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, IntoDiagnostic,
-    PResult, StashKey,
+    AddToDiagnostic, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, PResult,
+    StashKey,
 };
 use rustc_macros::Subdiagnostic;
 use rustc_session::errors::{report_lit_error, ExprParenthesesNeeded};
@@ -1255,21 +1255,21 @@ impl<'a> Parser<'a> {
                             // that of the open delim in `TokenTreesReader::parse_token_tree`, even if they are different.
                             self.span_to_snippet(close_paren).is_ok_and(|snippet| snippet == ")")
                         {
-                            let mut replacement_err = errors::ParenthesesWithStructFields {
-                                span,
-                                r#type: path,
-                                braces_for_struct: errors::BracesForStructLiteral {
-                                    first: open_paren,
-                                    second: close_paren,
-                                },
-                                no_fields_for_fn: errors::NoFieldsForFnCall {
-                                    fields: fields
-                                        .into_iter()
-                                        .map(|field| field.span.until(field.expr.span))
-                                        .collect(),
-                                },
-                            }
-                            .into_diagnostic(self.dcx());
+                            let mut replacement_err =
+                                self.dcx().create_err(errors::ParenthesesWithStructFields {
+                                    span,
+                                    r#type: path,
+                                    braces_for_struct: errors::BracesForStructLiteral {
+                                        first: open_paren,
+                                        second: close_paren,
+                                    },
+                                    no_fields_for_fn: errors::NoFieldsForFnCall {
+                                        fields: fields
+                                            .into_iter()
+                                            .map(|field| field.span.until(field.expr.span))
+                                            .collect(),
+                                    },
+                                });
                             replacement_err.emit();
 
                             let old_err = mem::replace(err, replacement_err);
@@ -1883,8 +1883,7 @@ impl<'a> Parser<'a> {
         self.bump(); // `#`
 
         let Some((ident, false)) = self.token.ident() else {
-            let err =
-                errors::ExpectedBuiltinIdent { span: self.token.span }.into_diagnostic(self.dcx());
+            let err = self.dcx().create_err(errors::ExpectedBuiltinIdent { span: self.token.span });
             return Err(err);
         };
         self.sess.gated_spans.gate(sym::builtin_syntax, ident.span);
@@ -1894,8 +1893,10 @@ impl<'a> Parser<'a> {
         let ret = if let Some(res) = parse(self, lo, ident)? {
             Ok(res)
         } else {
-            let err = errors::UnknownBuiltinConstruct { span: lo.to(ident.span), name: ident.name }
-                .into_diagnostic(self.dcx());
+            let err = self.dcx().create_err(errors::UnknownBuiltinConstruct {
+                span: lo.to(ident.span),
+                name: ident.name,
+            });
             return Err(err);
         };
         self.expect(&TokenKind::CloseDelim(Delimiter::Parenthesis))?;
@@ -1958,8 +1959,9 @@ impl<'a> Parser<'a> {
             && let token::NtExpr(e) | token::NtLiteral(e) = &nt.0
             && matches!(e.kind, ExprKind::Err)
         {
-            let mut err = errors::InvalidInterpolatedExpression { span: self.token.span }
-                .into_diagnostic(self.dcx());
+            let mut err = self
+                .dcx()
+                .create_err(errors::InvalidInterpolatedExpression { span: self.token.span });
             err.downgrade_to_delayed_bug();
             return Err(err);
         }
@@ -2168,10 +2170,10 @@ impl<'a> Parser<'a> {
                         .span_to_snippet(snapshot.token.span)
                         .is_ok_and(|snippet| snippet == "]") =>
                 {
-                    return Err(errors::MissingSemicolonBeforeArray {
+                    return Err(self.dcx().create_err(errors::MissingSemicolonBeforeArray {
                         open_delim: open_delim_span,
                         semicolon: prev_span.shrink_to_hi(),
-                    }.into_diagnostic(self.dcx()));
+                    }));
                 }
                 Ok(_) => (),
                 Err(err) => err.cancel(),
@@ -2318,8 +2320,9 @@ impl<'a> Parser<'a> {
             // Check for `move async` and recover
             if self.check_keyword(kw::Async) {
                 let move_async_span = self.token.span.with_lo(self.prev_token.span.data().lo);
-                Err(errors::AsyncMoveOrderIncorrect { span: move_async_span }
-                    .into_diagnostic(self.dcx()))
+                Err(self
+                    .dcx()
+                    .create_err(errors::AsyncMoveOrderIncorrect { span: move_async_span }))
             } else {
                 Ok(CaptureBy::Value { move_kw: move_kw_span })
             }
@@ -2509,7 +2512,7 @@ impl<'a> Parser<'a> {
             };
             if self.prev_token.kind == token::BinOp(token::Or) {
                 // This was part of a closure, the that part of the parser recover.
-                return Err(err.into_diagnostic(self.dcx()));
+                return Err(self.dcx().create_err(err));
             } else {
                 Some(self.sess.emit_err(err))
             }
@@ -3193,7 +3196,7 @@ impl<'a> Parser<'a> {
     fn parse_try_block(&mut self, span_lo: Span) -> PResult<'a, P<Expr>> {
         let (attrs, body) = self.parse_inner_attrs_and_block()?;
         if self.eat_keyword(kw::Catch) {
-            Err(errors::CatchAfterTry { span: self.prev_token.span }.into_diagnostic(self.dcx()))
+            Err(self.dcx().create_err(errors::CatchAfterTry { span: self.prev_token.span }))
         } else {
             let span = span_lo.to(body.span);
             self.sess.gated_spans.gate(sym::try_blocks, span);
@@ -3530,12 +3533,11 @@ impl<'a> Parser<'a> {
                         || t == &token::CloseDelim(Delimiter::Parenthesis)
                 });
             if is_wrong {
-                return Err(errors::ExpectedStructField {
+                return Err(this.dcx().create_err(errors::ExpectedStructField {
                     span: this.look_ahead(1, |t| t.span),
                     ident_span: this.token.span,
                     token: this.look_ahead(1, |t| t.clone()),
-                }
-                .into_diagnostic(&self.sess.dcx));
+                }));
             }
             let (ident, expr) = if is_shorthand {
                 // Mimic `x: x` for the `x` field shorthand.
-- 
cgit 1.4.1-3-g733a5


From 27d6539a46123dcdb6fae6e043b8c1c12b3e0d6f Mon Sep 17 00:00:00 2001
From: Eric Holk <ericholk@microsoft.com>
Date: Fri, 8 Dec 2023 14:51:50 -0800
Subject: Plumb awaitness of for loops

---
 compiler/rustc_ast/src/ast.rs                      | 13 +++++++++---
 compiler/rustc_ast/src/mut_visit.rs                |  2 +-
 compiler/rustc_ast/src/util/classify.rs            | 14 ++++++++++---
 compiler/rustc_ast/src/visit.rs                    | 10 ++++-----
 compiler/rustc_ast_lowering/src/expr.rs            |  9 ++++----
 compiler/rustc_ast_passes/src/feature_gate.rs      |  1 +
 compiler/rustc_ast_pretty/src/pprust/state/expr.rs | 10 ++++++---
 .../rustc_builtin_macros/src/assert/context.rs     |  2 +-
 compiler/rustc_feature/src/unstable.rs             |  2 ++
 compiler/rustc_lint/src/unused.rs                  |  6 +++---
 compiler/rustc_parse/src/parser/expr.rs            | 20 ++++++++++++------
 compiler/rustc_resolve/src/late.rs                 |  6 +++---
 compiler/rustc_resolve/src/late/diagnostics.rs     |  2 +-
 compiler/rustc_span/src/symbol.rs                  |  1 +
 .../clippy/clippy_lints/src/needless_continue.rs   |  6 +++++-
 .../clippy/clippy_lints/src/redundant_else.rs      |  2 +-
 .../src/suspicious_operation_groupings.rs          |  2 +-
 src/tools/clippy/clippy_utils/src/ast_utils.rs     | 19 ++++++++++++++---
 src/tools/clippy/clippy_utils/src/sugg.rs          |  2 +-
 src/tools/rustfmt/src/closures.rs                  |  4 ++--
 src/tools/rustfmt/src/expr.rs                      | 24 +++++++++++++++-------
 src/tools/rustfmt/src/matches.rs                   |  2 +-
 src/tools/rustfmt/src/overflow.rs                  |  2 +-
 src/tools/rustfmt/src/utils.rs                     |  4 ++--
 tests/ui/async-await/feature-async-for-loop.rs     | 14 +++++++++++++
 tests/ui/async-await/feature-async-for-loop.stderr | 11 ++++++++++
 26 files changed, 137 insertions(+), 53 deletions(-)
 create mode 100644 tests/ui/async-await/feature-async-for-loop.rs
 create mode 100644 tests/ui/async-await/feature-async-for-loop.stderr

(limited to 'compiler/rustc_parse/src/parser/expr.rs')

diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index 9d543563c0f..8a0fbdd1357 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -1274,7 +1274,7 @@ impl Expr {
             ExprKind::Let(..) => ExprPrecedence::Let,
             ExprKind::If(..) => ExprPrecedence::If,
             ExprKind::While(..) => ExprPrecedence::While,
-            ExprKind::ForLoop(..) => ExprPrecedence::ForLoop,
+            ExprKind::ForLoop { .. } => ExprPrecedence::ForLoop,
             ExprKind::Loop(..) => ExprPrecedence::Loop,
             ExprKind::Match(..) => ExprPrecedence::Match,
             ExprKind::Closure(..) => ExprPrecedence::Closure,
@@ -1436,10 +1436,10 @@ pub enum ExprKind {
     While(P<Expr>, P<Block>, Option<Label>),
     /// A `for` loop, with an optional label.
     ///
-    /// `'label: for pat in expr { block }`
+    /// `'label: for await? pat in iter { block }`
     ///
     /// This is desugared to a combination of `loop` and `match` expressions.
-    ForLoop(P<Pat>, P<Expr>, P<Block>, Option<Label>),
+    ForLoop { pat: P<Pat>, iter: P<Expr>, body: P<Block>, label: Option<Label>, kind: ForLoopKind },
     /// Conditionless loop (can be exited with `break`, `continue`, or `return`).
     ///
     /// `'label: loop { block }`
@@ -1542,6 +1542,13 @@ pub enum ExprKind {
     Err,
 }
 
+/// Used to differentiate between `for` loops and `for await` loops.
+#[derive(Clone, Copy, Encodable, Decodable, Debug, PartialEq, Eq)]
+pub enum ForLoopKind {
+    For,
+    ForAwait,
+}
+
 /// Used to differentiate between `async {}` blocks and `gen {}` blocks.
 #[derive(Clone, Encodable, Decodable, Debug, PartialEq, Eq)]
 pub enum GenBlockKind {
diff --git a/compiler/rustc_ast/src/mut_visit.rs b/compiler/rustc_ast/src/mut_visit.rs
index 10b2025f937..d0afd90e5e7 100644
--- a/compiler/rustc_ast/src/mut_visit.rs
+++ b/compiler/rustc_ast/src/mut_visit.rs
@@ -1389,7 +1389,7 @@ pub fn noop_visit_expr<T: MutVisitor>(
             vis.visit_block(body);
             visit_opt(label, |label| vis.visit_label(label));
         }
-        ExprKind::ForLoop(pat, iter, body, label) => {
+        ExprKind::ForLoop { pat, iter, body, label, kind: _ } => {
             vis.visit_pat(pat);
             vis.visit_expr(iter);
             vis.visit_block(body);
diff --git a/compiler/rustc_ast/src/util/classify.rs b/compiler/rustc_ast/src/util/classify.rs
index 4dece079783..65036bcdc36 100644
--- a/compiler/rustc_ast/src/util/classify.rs
+++ b/compiler/rustc_ast/src/util/classify.rs
@@ -19,7 +19,7 @@ pub fn expr_requires_semi_to_be_stmt(e: &ast::Expr) -> bool {
             | ast::ExprKind::Block(..)
             | ast::ExprKind::While(..)
             | ast::ExprKind::Loop(..)
-            | ast::ExprKind::ForLoop(..)
+            | ast::ExprKind::ForLoop { .. }
             | ast::ExprKind::TryBlock(..)
             | ast::ExprKind::ConstBlock(..)
     )
@@ -48,8 +48,16 @@ pub fn expr_trailing_brace(mut expr: &ast::Expr) -> Option<&ast::Expr> {
             Closure(closure) => {
                 expr = &closure.body;
             }
-            Gen(..) | Block(..) | ForLoop(..) | If(..) | Loop(..) | Match(..) | Struct(..)
-            | TryBlock(..) | While(..) | ConstBlock(_) => break Some(expr),
+            Gen(..)
+            | Block(..)
+            | ForLoop { .. }
+            | If(..)
+            | Loop(..)
+            | Match(..)
+            | Struct(..)
+            | TryBlock(..)
+            | While(..)
+            | ConstBlock(_) => break Some(expr),
 
             // FIXME: These can end in `}`, but changing these would break stable code.
             InlineAsm(_) | OffsetOf(_, _) | MacCall(_) | IncludedBytes(_) | FormatArgs(_) => {
diff --git a/compiler/rustc_ast/src/visit.rs b/compiler/rustc_ast/src/visit.rs
index 27f1b84f372..45261ca48fc 100644
--- a/compiler/rustc_ast/src/visit.rs
+++ b/compiler/rustc_ast/src/visit.rs
@@ -844,11 +844,11 @@ pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
             visitor.visit_expr(subexpression);
             visitor.visit_block(block);
         }
-        ExprKind::ForLoop(pattern, subexpression, block, opt_label) => {
-            walk_list!(visitor, visit_label, opt_label);
-            visitor.visit_pat(pattern);
-            visitor.visit_expr(subexpression);
-            visitor.visit_block(block);
+        ExprKind::ForLoop { pat, iter, body, label, kind: _ } => {
+            walk_list!(visitor, visit_label, label);
+            visitor.visit_pat(pat);
+            visitor.visit_expr(iter);
+            visitor.visit_block(body);
         }
         ExprKind::Loop(block, opt_label, _) => {
             walk_list!(visitor, visit_label, opt_label);
diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs
index 11b5131b8d7..c2d91b09453 100644
--- a/compiler/rustc_ast_lowering/src/expr.rs
+++ b/compiler/rustc_ast_lowering/src/expr.rs
@@ -56,12 +56,12 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     return ex;
                 }
                 // Desugar `ExprForLoop`
-                // from: `[opt_ident]: for <pat> in <head> <body>`
+                // from: `[opt_ident]: for await? <pat> in <iter> <body>`
                 //
                 // This also needs special handling because the HirId of the returned `hir::Expr` will not
                 // correspond to the `e.id`, so `lower_expr_for` handles attribute lowering itself.
-                ExprKind::ForLoop(pat, head, body, opt_label) => {
-                    return self.lower_expr_for(e, pat, head, body, *opt_label);
+                ExprKind::ForLoop { pat, iter, body, label, kind } => {
+                    return self.lower_expr_for(e, pat, iter, body, *label, *kind);
                 }
                 _ => (),
             }
@@ -337,7 +337,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 ),
                 ExprKind::Try(sub_expr) => self.lower_expr_try(e.span, sub_expr),
 
-                ExprKind::Paren(_) | ExprKind::ForLoop(..) => {
+                ExprKind::Paren(_) | ExprKind::ForLoop{..} => {
                     unreachable!("already handled")
                 }
 
@@ -1673,6 +1673,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         head: &Expr,
         body: &Block,
         opt_label: Option<Label>,
+        _loop_kind: ForLoopKind,
     ) -> hir::Expr<'hir> {
         let head = self.lower_expr_mut(head);
         let pat = self.lower_pat(pat);
diff --git a/compiler/rustc_ast_passes/src/feature_gate.rs b/compiler/rustc_ast_passes/src/feature_gate.rs
index 142cdd15e64..411c10df0c2 100644
--- a/compiler/rustc_ast_passes/src/feature_gate.rs
+++ b/compiler/rustc_ast_passes/src/feature_gate.rs
@@ -526,6 +526,7 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
         "async closures are unstable",
         "to use an async block, remove the `||`: `async {`"
     );
+    gate_all!(async_for_loop, "`for await` loops are experimental");
     gate_all!(
         closure_lifetime_binder,
         "`for<...>` binders for closures are experimental",
diff --git a/compiler/rustc_ast_pretty/src/pprust/state/expr.rs b/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
index f5ffcddb83d..f868beec812 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
@@ -1,5 +1,6 @@
 use crate::pp::Breaks::Inconsistent;
 use crate::pprust::state::{AnnNode, PrintState, State, INDENT_UNIT};
+use ast::ForLoopKind;
 use itertools::{Itertools, Position};
 use rustc_ast::ptr::P;
 use rustc_ast::token;
@@ -418,20 +419,23 @@ impl<'a> State<'a> {
                 self.space();
                 self.print_block_with_attrs(blk, attrs);
             }
-            ast::ExprKind::ForLoop(pat, iter, blk, opt_label) => {
-                if let Some(label) = opt_label {
+            ast::ExprKind::ForLoop { pat, iter, body, label, kind } => {
+                if let Some(label) = label {
                     self.print_ident(label.ident);
                     self.word_space(":");
                 }
                 self.cbox(0);
                 self.ibox(0);
                 self.word_nbsp("for");
+                if kind == &ForLoopKind::ForAwait {
+                    self.word_nbsp("await");
+                }
                 self.print_pat(pat);
                 self.space();
                 self.word_space("in");
                 self.print_expr_as_cond(iter);
                 self.space();
-                self.print_block_with_attrs(blk, attrs);
+                self.print_block_with_attrs(body, attrs);
             }
             ast::ExprKind::Loop(blk, opt_label, _) => {
                 if let Some(label) = opt_label {
diff --git a/compiler/rustc_builtin_macros/src/assert/context.rs b/compiler/rustc_builtin_macros/src/assert/context.rs
index b54e119189a..4e07122a5c4 100644
--- a/compiler/rustc_builtin_macros/src/assert/context.rs
+++ b/compiler/rustc_builtin_macros/src/assert/context.rs
@@ -303,7 +303,7 @@ impl<'cx, 'a> Context<'cx, 'a> {
             | ExprKind::Continue(_)
             | ExprKind::Err
             | ExprKind::Field(_, _)
-            | ExprKind::ForLoop(_, _, _, _)
+            | ExprKind::ForLoop {..}
             | ExprKind::FormatArgs(_)
             | ExprKind::IncludedBytes(..)
             | ExprKind::InlineAsm(_)
diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs
index bbf5e031175..fdd4bb755e4 100644
--- a/compiler/rustc_feature/src/unstable.rs
+++ b/compiler/rustc_feature/src/unstable.rs
@@ -357,6 +357,8 @@ declare_features! (
     (unstable, async_closure, "1.37.0", Some(62290)),
     /// Allows `#[track_caller]` on async functions.
     (unstable, async_fn_track_caller, "1.73.0", Some(110011)),
+    /// Allows `for await` loops.
+    (unstable, async_for_loop, "CURRENT_RUSTC_VERSION", None),
     /// Allows builtin # foo() syntax
     (unstable, builtin_syntax, "1.71.0", Some(110680)),
     /// Treat `extern "C"` function as nounwind.
diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs
index 34cdee4ec5c..0386f2ec56c 100644
--- a/compiler/rustc_lint/src/unused.rs
+++ b/compiler/rustc_lint/src/unused.rs
@@ -852,8 +852,8 @@ trait UnusedDelimLint {
                 (cond, UnusedDelimsCtx::WhileCond, true, Some(left), Some(right), true)
             }
 
-            ForLoop(_, ref cond, ref block, ..) => {
-                (cond, UnusedDelimsCtx::ForIterExpr, true, None, Some(block.span.lo()), true)
+            ForLoop { ref iter, ref body, .. } => {
+                (iter, UnusedDelimsCtx::ForIterExpr, true, None, Some(body.span.lo()), true)
             }
 
             Match(ref head, _) if Self::LINT_EXPR_IN_PATTERN_MATCHING_CTX => {
@@ -1085,7 +1085,7 @@ impl EarlyLintPass for UnusedParens {
         }
 
         match e.kind {
-            ExprKind::Let(ref pat, _, _, _) | ExprKind::ForLoop(ref pat, ..) => {
+            ExprKind::Let(ref pat, _, _, _) | ExprKind::ForLoop { ref pat, .. } => {
                 self.check_unused_parens_pat(cx, pat, false, false, (true, true));
             }
             // We ignore parens in cases like `if (((let Some(0) = Some(1))))` because we already
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index cd3e8b92f2f..f424040e4ea 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -10,7 +10,7 @@ use super::{
 use crate::errors;
 use crate::maybe_recover_from_interpolated_ty_qpath;
 use ast::mut_visit::{noop_visit_expr, MutVisitor};
-use ast::{CoroutineKind, GenBlockKind, Pat, Path, PathSegment};
+use ast::{CoroutineKind, ForLoopKind, GenBlockKind, Pat, Path, PathSegment};
 use core::mem;
 use rustc_ast::ptr::P;
 use rustc_ast::token::{self, Delimiter, Token, TokenKind};
@@ -1801,7 +1801,7 @@ impl<'a> Parser<'a> {
                     && matches!(
                         expr.kind,
                         ExprKind::While(_, _, None)
-                            | ExprKind::ForLoop(_, _, _, None)
+                            | ExprKind::ForLoop { label: None, .. }
                             | ExprKind::Loop(_, None, _)
                             | ExprKind::Block(_, None)
                     )
@@ -2682,8 +2682,16 @@ impl<'a> Parser<'a> {
         Ok((pat, expr))
     }
 
-    /// Parses `for <src_pat> in <src_expr> <src_loop_block>` (`for` token already eaten).
+    /// Parses `for await? <src_pat> in <src_expr> <src_loop_block>` (`for` token already eaten).
     fn parse_expr_for(&mut self, opt_label: Option<Label>, lo: Span) -> PResult<'a, P<Expr>> {
+        let is_await = self.eat_keyword(kw::Await);
+
+        if is_await {
+            self.sess.gated_spans.gate(sym::async_for_loop, self.prev_token.span);
+        }
+
+        let kind = if is_await { ForLoopKind::ForAwait } else { ForLoopKind::For };
+
         let (pat, expr) = self.parse_for_head()?;
         // Recover from missing expression in `for` loop
         if matches!(expr.kind, ExprKind::Block(..))
@@ -2696,13 +2704,13 @@ impl<'a> Parser<'a> {
             let block = self.mk_block(thin_vec![], BlockCheckMode::Default, self.prev_token.span);
             return Ok(self.mk_expr(
                 lo.to(self.prev_token.span),
-                ExprKind::ForLoop(pat, err_expr, block, opt_label),
+                ExprKind::ForLoop { pat, iter: err_expr, body: block, label: opt_label, kind },
             ));
         }
 
         let (attrs, loop_block) = self.parse_inner_attrs_and_block()?;
 
-        let kind = ExprKind::ForLoop(pat, expr, loop_block, opt_label);
+        let kind = ExprKind::ForLoop { pat, iter: expr, body: loop_block, label: opt_label, kind };
 
         self.recover_loop_else("for", lo)?;
 
@@ -3798,7 +3806,7 @@ impl MutVisitor for CondChecker<'_> {
             | ExprKind::Lit(_)
             | ExprKind::If(_, _, _)
             | ExprKind::While(_, _, _)
-            | ExprKind::ForLoop(_, _, _, _)
+            | ExprKind::ForLoop { .. }
             | ExprKind::Loop(_, _, _)
             | ExprKind::Match(_, _)
             | ExprKind::Closure(_)
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 037179350f0..7e275a207e7 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -4252,11 +4252,11 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
                 });
             }
 
-            ExprKind::ForLoop(ref pat, ref iter_expr, ref block, label) => {
-                self.visit_expr(iter_expr);
+            ExprKind::ForLoop { ref pat, ref iter, ref body, label, kind: _ } => {
+                self.visit_expr(iter);
                 self.with_rib(ValueNS, RibKind::Normal, |this| {
                     this.resolve_pattern_top(pat, PatternSource::For);
-                    this.resolve_labeled_block(label, expr.id, block);
+                    this.resolve_labeled_block(label, expr.id, body);
                 });
             }
 
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index d767ed74139..b4dc9d35b42 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -1409,7 +1409,7 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
                             | ExprKind::Unary(..)
                             | ExprKind::If(..)
                             | ExprKind::While(..)
-                            | ExprKind::ForLoop(..)
+                            | ExprKind::ForLoop { .. }
                             | ExprKind::Match(..),
                         ..
                     }),
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 0333b5f04c3..2e7037532b5 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -426,6 +426,7 @@ symbols! {
         async_closure,
         async_fn_in_trait,
         async_fn_track_caller,
+        async_for_loop,
         async_iterator,
         atomic,
         atomic_mod,
diff --git a/src/tools/clippy/clippy_lints/src/needless_continue.rs b/src/tools/clippy/clippy_lints/src/needless_continue.rs
index 4b9ab50e4fd..ff72b5e69ef 100644
--- a/src/tools/clippy/clippy_lints/src/needless_continue.rs
+++ b/src/tools/clippy/clippy_lints/src/needless_continue.rs
@@ -220,7 +220,11 @@ where
     F: FnMut(&ast::Block, Option<&ast::Label>),
 {
     if let ast::ExprKind::While(_, loop_block, label)
-    | ast::ExprKind::ForLoop(_, _, loop_block, label)
+    | ast::ExprKind::ForLoop {
+        body: loop_block,
+        label,
+        ..
+    }
     | ast::ExprKind::Loop(loop_block, label, ..) = &expr.kind
     {
         func(loop_block, label.as_ref());
diff --git a/src/tools/clippy/clippy_lints/src/redundant_else.rs b/src/tools/clippy/clippy_lints/src/redundant_else.rs
index 001686c84f8..fb434fb7450 100644
--- a/src/tools/clippy/clippy_lints/src/redundant_else.rs
+++ b/src/tools/clippy/clippy_lints/src/redundant_else.rs
@@ -111,7 +111,7 @@ impl<'ast> Visitor<'ast> for BreakVisitor {
             ExprKind::If(_, ref then, Some(ref els)) => self.check_block(then) && self.check_expr(els),
             ExprKind::If(_, _, None)
             // ignore loops for simplicity
-            | ExprKind::While(..) | ExprKind::ForLoop(..) | ExprKind::Loop(..) => false,
+            | ExprKind::While(..) | ExprKind::ForLoop { .. } | ExprKind::Loop(..) => false,
             _ => {
                 walk_expr(self, expr);
                 return;
diff --git a/src/tools/clippy/clippy_lints/src/suspicious_operation_groupings.rs b/src/tools/clippy/clippy_lints/src/suspicious_operation_groupings.rs
index 8b9d9bade91..60e9d262e7e 100644
--- a/src/tools/clippy/clippy_lints/src/suspicious_operation_groupings.rs
+++ b/src/tools/clippy/clippy_lints/src/suspicious_operation_groupings.rs
@@ -554,7 +554,7 @@ fn ident_difference_expr_with_base_location(
         | (Closure(_), Closure(_))
         | (Match(_, _), Match(_, _))
         | (Loop(_, _, _), Loop(_, _, _))
-        | (ForLoop(_, _, _, _), ForLoop(_, _, _, _))
+        | (ForLoop { .. }, ForLoop { .. })
         | (While(_, _, _), While(_, _, _))
         | (If(_, _, _), If(_, _, _))
         | (Let(_, _, _, _), Let(_, _, _, _))
diff --git a/src/tools/clippy/clippy_utils/src/ast_utils.rs b/src/tools/clippy/clippy_utils/src/ast_utils.rs
index e36f2fa87a7..be3c418ef70 100644
--- a/src/tools/clippy/clippy_utils/src/ast_utils.rs
+++ b/src/tools/clippy/clippy_utils/src/ast_utils.rs
@@ -169,9 +169,22 @@ pub fn eq_expr(l: &Expr, r: &Expr) -> bool {
         (Let(lp, le, _, _), Let(rp, re, _, _)) => eq_pat(lp, rp) && eq_expr(le, re),
         (If(lc, lt, le), If(rc, rt, re)) => eq_expr(lc, rc) && eq_block(lt, rt) && eq_expr_opt(le, re),
         (While(lc, lt, ll), While(rc, rt, rl)) => eq_label(ll, rl) && eq_expr(lc, rc) && eq_block(lt, rt),
-        (ForLoop(lp, li, lt, ll), ForLoop(rp, ri, rt, rl)) => {
-            eq_label(ll, rl) && eq_pat(lp, rp) && eq_expr(li, ri) && eq_block(lt, rt)
-        },
+        (
+            ForLoop {
+                pat: lp,
+                iter: li,
+                body: lt,
+                label: ll,
+                kind: lk,
+            },
+            ForLoop {
+                pat: rp,
+                iter: ri,
+                body: rt,
+                label: rl,
+                kind: rk,
+            },
+        ) => eq_label(ll, rl) && eq_pat(lp, rp) && eq_expr(li, ri) && eq_block(lt, rt) && lk == rk,
         (Loop(lt, ll, _), Loop(rt, rl, _)) => eq_label(ll, rl) && eq_block(lt, rt),
         (Block(lb, ll), Block(rb, rl)) => eq_label(ll, rl) && eq_block(lb, rb),
         (TryBlock(l), TryBlock(r)) => eq_block(l, r),
diff --git a/src/tools/clippy/clippy_utils/src/sugg.rs b/src/tools/clippy/clippy_utils/src/sugg.rs
index 9b2bc8df1f3..c86362c427c 100644
--- a/src/tools/clippy/clippy_utils/src/sugg.rs
+++ b/src/tools/clippy/clippy_utils/src/sugg.rs
@@ -197,7 +197,7 @@ impl<'a> Sugg<'a> {
             | ast::ExprKind::Continue(..)
             | ast::ExprKind::Yield(..)
             | ast::ExprKind::Field(..)
-            | ast::ExprKind::ForLoop(..)
+            | ast::ExprKind::ForLoop { .. }
             | ast::ExprKind::Index(..)
             | ast::ExprKind::InlineAsm(..)
             | ast::ExprKind::OffsetOf(..)
diff --git a/src/tools/rustfmt/src/closures.rs b/src/tools/rustfmt/src/closures.rs
index f698f494ae5..5bf29441b54 100644
--- a/src/tools/rustfmt/src/closures.rs
+++ b/src/tools/rustfmt/src/closures.rs
@@ -448,7 +448,7 @@ fn is_block_closure_forced(context: &RewriteContext<'_>, expr: &ast::Expr) -> bo
 
 fn is_block_closure_forced_inner(expr: &ast::Expr, version: Version) -> bool {
     match expr.kind {
-        ast::ExprKind::If(..) | ast::ExprKind::While(..) | ast::ExprKind::ForLoop(..) => true,
+        ast::ExprKind::If(..) | ast::ExprKind::While(..) | ast::ExprKind::ForLoop { .. } => true,
         ast::ExprKind::Loop(..) if version == Version::Two => true,
         ast::ExprKind::AddrOf(_, _, ref expr)
         | ast::ExprKind::Try(ref expr)
@@ -473,7 +473,7 @@ fn expr_requires_semi_to_be_stmt(e: &ast::Expr) -> bool {
         | ast::ExprKind::Block(..)
         | ast::ExprKind::While(..)
         | ast::ExprKind::Loop(..)
-        | ast::ExprKind::ForLoop(..)
+        | ast::ExprKind::ForLoop { .. }
         | ast::ExprKind::TryBlock(..) => false,
         _ => true,
     }
diff --git a/src/tools/rustfmt/src/expr.rs b/src/tools/rustfmt/src/expr.rs
index a68bd6694ba..7808f891336 100644
--- a/src/tools/rustfmt/src/expr.rs
+++ b/src/tools/rustfmt/src/expr.rs
@@ -3,7 +3,7 @@ use std::cmp::min;
 
 use itertools::Itertools;
 use rustc_ast::token::{Delimiter, Lit, LitKind};
-use rustc_ast::{ast, ptr, token};
+use rustc_ast::{ast, ptr, token, ForLoopKind};
 use rustc_span::{BytePos, Span};
 
 use crate::chains::rewrite_chain;
@@ -134,7 +134,7 @@ pub(crate) fn format_expr(
         }
         ast::ExprKind::Let(ref pat, ref expr, _span, _) => rewrite_let(context, shape, pat, expr),
         ast::ExprKind::If(..)
-        | ast::ExprKind::ForLoop(..)
+        | ast::ExprKind::ForLoop { .. }
         | ast::ExprKind::Loop(..)
         | ast::ExprKind::While(..) => to_control_flow(expr, expr_type)
             .and_then(|control_flow| control_flow.rewrite(context, shape)),
@@ -682,9 +682,15 @@ fn to_control_flow(expr: &ast::Expr, expr_type: ExprType) -> Option<ControlFlow<
                 expr.span,
             ))
         }
-        ast::ExprKind::ForLoop(ref pat, ref cond, ref block, label) => {
-            Some(ControlFlow::new_for(pat, cond, block, label, expr.span))
-        }
+        ast::ExprKind::ForLoop {
+            ref pat,
+            ref iter,
+            ref body,
+            label,
+            kind,
+        } => Some(ControlFlow::new_for(
+            pat, iter, body, label, expr.span, kind,
+        )),
         ast::ExprKind::Loop(ref block, label, _) => {
             Some(ControlFlow::new_loop(block, label, expr.span))
         }
@@ -771,6 +777,7 @@ impl<'a> ControlFlow<'a> {
         block: &'a ast::Block,
         label: Option<ast::Label>,
         span: Span,
+        kind: ForLoopKind,
     ) -> ControlFlow<'a> {
         ControlFlow {
             cond: Some(cond),
@@ -778,7 +785,10 @@ impl<'a> ControlFlow<'a> {
             else_block: None,
             label,
             pat: Some(pat),
-            keyword: "for",
+            keyword: match kind {
+                ForLoopKind::For => "for",
+                ForLoopKind::ForAwait => "for await",
+            },
             matcher: "",
             connector: " in",
             allow_single_line: false,
@@ -1364,7 +1374,7 @@ pub(crate) fn can_be_overflowed_expr(
                 || context.config.overflow_delimited_expr()
         }
         ast::ExprKind::If(..)
-        | ast::ExprKind::ForLoop(..)
+        | ast::ExprKind::ForLoop { .. }
         | ast::ExprKind::Loop(..)
         | ast::ExprKind::While(..) => {
             context.config.combine_control_expr() && context.use_block_indent() && args_len == 1
diff --git a/src/tools/rustfmt/src/matches.rs b/src/tools/rustfmt/src/matches.rs
index ef509b56837..5a00984d4c0 100644
--- a/src/tools/rustfmt/src/matches.rs
+++ b/src/tools/rustfmt/src/matches.rs
@@ -591,7 +591,7 @@ fn can_flatten_block_around_this(body: &ast::Expr) -> bool {
         ast::ExprKind::If(..) => false,
         // We do not allow collapsing a block around expression with condition
         // to avoid it being cluttered with match arm.
-        ast::ExprKind::ForLoop(..) | ast::ExprKind::While(..) => false,
+        ast::ExprKind::ForLoop { .. } | ast::ExprKind::While(..) => false,
         ast::ExprKind::Loop(..)
         | ast::ExprKind::Match(..)
         | ast::ExprKind::Block(..)
diff --git a/src/tools/rustfmt/src/overflow.rs b/src/tools/rustfmt/src/overflow.rs
index d81bf24dbd1..f46583b1c89 100644
--- a/src/tools/rustfmt/src/overflow.rs
+++ b/src/tools/rustfmt/src/overflow.rs
@@ -409,7 +409,7 @@ impl<'a> Context<'a> {
                     // When overflowing the expressions which consists of a control flow
                     // expression, avoid condition to use multi line.
                     ast::ExprKind::If(..)
-                    | ast::ExprKind::ForLoop(..)
+                    | ast::ExprKind::ForLoop { .. }
                     | ast::ExprKind::Loop(..)
                     | ast::ExprKind::While(..)
                     | ast::ExprKind::Match(..) => {
diff --git a/src/tools/rustfmt/src/utils.rs b/src/tools/rustfmt/src/utils.rs
index 7d7bbf11529..642b6603b1e 100644
--- a/src/tools/rustfmt/src/utils.rs
+++ b/src/tools/rustfmt/src/utils.rs
@@ -295,7 +295,7 @@ pub(crate) fn semicolon_for_stmt(
 ) -> bool {
     match stmt.kind {
         ast::StmtKind::Semi(ref expr) => match expr.kind {
-            ast::ExprKind::While(..) | ast::ExprKind::Loop(..) | ast::ExprKind::ForLoop(..) => {
+            ast::ExprKind::While(..) | ast::ExprKind::Loop(..) | ast::ExprKind::ForLoop { .. } => {
                 false
             }
             ast::ExprKind::Break(..) | ast::ExprKind::Continue(..) | ast::ExprKind::Ret(..) => {
@@ -476,7 +476,7 @@ pub(crate) fn is_block_expr(context: &RewriteContext<'_>, expr: &ast::Expr, repr
         | ast::ExprKind::ConstBlock(..)
         | ast::ExprKind::Gen(..)
         | ast::ExprKind::Loop(..)
-        | ast::ExprKind::ForLoop(..)
+        | ast::ExprKind::ForLoop { .. }
         | ast::ExprKind::TryBlock(..)
         | ast::ExprKind::Match(..) => repr.contains('\n'),
         ast::ExprKind::Paren(ref expr)
diff --git a/tests/ui/async-await/feature-async-for-loop.rs b/tests/ui/async-await/feature-async-for-loop.rs
new file mode 100644
index 00000000000..6d32b3ca700
--- /dev/null
+++ b/tests/ui/async-await/feature-async-for-loop.rs
@@ -0,0 +1,14 @@
+// edition:2021
+// gate-test-async_for_loop
+
+#![feature(async_iter_from_iter, async_iterator)]
+
+fn f() {
+    let _ = async {
+        for await _i in core::async_iter::from_iter(0..3) {
+            //~^ ERROR `for await` loops are experimental
+        }
+    };
+}
+
+fn main() {}
diff --git a/tests/ui/async-await/feature-async-for-loop.stderr b/tests/ui/async-await/feature-async-for-loop.stderr
new file mode 100644
index 00000000000..7e6d83fe5b6
--- /dev/null
+++ b/tests/ui/async-await/feature-async-for-loop.stderr
@@ -0,0 +1,11 @@
+error[E0658]: `for await` loops are experimental
+  --> $DIR/feature-async-for-loop.rs:8:13
+   |
+LL |         for await _i in core::async_iter::from_iter(0..3) {
+   |             ^^^^^
+   |
+   = help: add `#![feature(async_for_loop)]` to the crate attributes to enable
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0658`.
-- 
cgit 1.4.1-3-g733a5


From 397f4a15bbcad7d22f8c09edb72a0d49e3da80c9 Mon Sep 17 00:00:00 2001
From: Eric Holk <ericholk@microsoft.com>
Date: Tue, 12 Dec 2023 17:33:51 -0800
Subject: Add additional tests and update existing tests

---
 compiler/rustc_parse/src/parser/expr.rs            |  3 +-
 tests/ui/async-await/feature-async-for-loop.rs     |  9 ++++++
 tests/ui/async-await/feature-async-for-loop.stderr | 12 +++++++-
 tests/ui/async-await/for-await-2015.rs             | 10 +++++++
 tests/ui/async-await/for-await-consumes-iter.rs    | 20 ++++++++++++++
 .../ui/async-await/for-await-consumes-iter.stderr  | 27 ++++++++++++++++++
 tests/ui/async-await/for-await-passthrough.rs      | 32 ++++++++++++++++++++++
 7 files changed, 111 insertions(+), 2 deletions(-)
 create mode 100644 tests/ui/async-await/for-await-2015.rs
 create mode 100644 tests/ui/async-await/for-await-consumes-iter.rs
 create mode 100644 tests/ui/async-await/for-await-consumes-iter.stderr
 create mode 100644 tests/ui/async-await/for-await-passthrough.rs

(limited to 'compiler/rustc_parse/src/parser/expr.rs')

diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index f424040e4ea..85f785b3401 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -2684,7 +2684,8 @@ impl<'a> Parser<'a> {
 
     /// Parses `for await? <src_pat> in <src_expr> <src_loop_block>` (`for` token already eaten).
     fn parse_expr_for(&mut self, opt_label: Option<Label>, lo: Span) -> PResult<'a, P<Expr>> {
-        let is_await = self.eat_keyword(kw::Await);
+        let is_await =
+            self.token.uninterpolated_span().at_least_rust_2018() && self.eat_keyword(kw::Await);
 
         if is_await {
             self.sess.gated_spans.gate(sym::async_for_loop, self.prev_token.span);
diff --git a/tests/ui/async-await/feature-async-for-loop.rs b/tests/ui/async-await/feature-async-for-loop.rs
index 6d32b3ca700..42247dd14b0 100644
--- a/tests/ui/async-await/feature-async-for-loop.rs
+++ b/tests/ui/async-await/feature-async-for-loop.rs
@@ -11,4 +11,13 @@ fn f() {
     };
 }
 
+#[cfg(FALSE)]
+fn g() {
+    let _ = async {
+        for await _i in core::async_iter::from_iter(0..3) {
+            //~^ ERROR `for await` loops are experimental
+        }
+    };
+}
+
 fn main() {}
diff --git a/tests/ui/async-await/feature-async-for-loop.stderr b/tests/ui/async-await/feature-async-for-loop.stderr
index 7e6d83fe5b6..38f75821772 100644
--- a/tests/ui/async-await/feature-async-for-loop.stderr
+++ b/tests/ui/async-await/feature-async-for-loop.stderr
@@ -4,8 +4,18 @@ error[E0658]: `for await` loops are experimental
 LL |         for await _i in core::async_iter::from_iter(0..3) {
    |             ^^^^^
    |
+   = note: see issue #118898 <https://github.com/rust-lang/rust/issues/118898> for more information
    = help: add `#![feature(async_for_loop)]` to the crate attributes to enable
 
-error: aborting due to 1 previous error
+error[E0658]: `for await` loops are experimental
+  --> $DIR/feature-async-for-loop.rs:17:13
+   |
+LL |         for await _i in core::async_iter::from_iter(0..3) {
+   |             ^^^^^
+   |
+   = note: see issue #118898 <https://github.com/rust-lang/rust/issues/118898> for more information
+   = help: add `#![feature(async_for_loop)]` to the crate attributes to enable
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/async-await/for-await-2015.rs b/tests/ui/async-await/for-await-2015.rs
new file mode 100644
index 00000000000..c1b7c016d1f
--- /dev/null
+++ b/tests/ui/async-await/for-await-2015.rs
@@ -0,0 +1,10 @@
+// check-pass
+
+#![feature(async_for_loop)]
+
+// Make sure we don't break `for await` loops in the 2015 edition, where `await` was allowed as an
+// identifier.
+
+fn main() {
+    for await in 0..3 {}
+}
diff --git a/tests/ui/async-await/for-await-consumes-iter.rs b/tests/ui/async-await/for-await-consumes-iter.rs
new file mode 100644
index 00000000000..65bb9e88448
--- /dev/null
+++ b/tests/ui/async-await/for-await-consumes-iter.rs
@@ -0,0 +1,20 @@
+// edition: 2021
+#![feature(async_iterator, async_iter_from_iter, const_waker, async_for_loop, noop_waker)]
+
+use std::future::Future;
+
+// a test to make sure `for await` consumes the iterator
+
+async fn real_main() {
+    let iter = core::async_iter::from_iter(0..3);
+    let mut count = 0;
+    for await i in iter {
+    }
+    // make sure iter has been moved and we can't iterate over it again.
+    for await i in iter {
+        //~^ ERROR: use of moved value: `iter`
+    }
+}
+
+fn main() {
+}
diff --git a/tests/ui/async-await/for-await-consumes-iter.stderr b/tests/ui/async-await/for-await-consumes-iter.stderr
new file mode 100644
index 00000000000..48b2e8a51d8
--- /dev/null
+++ b/tests/ui/async-await/for-await-consumes-iter.stderr
@@ -0,0 +1,27 @@
+error[E0382]: use of moved value: `iter`
+  --> $DIR/for-await-consumes-iter.rs:14:20
+   |
+LL |     let iter = core::async_iter::from_iter(0..3);
+   |         ---- move occurs because `iter` has type `FromIter<std::ops::Range<i32>>`, which does not implement the `Copy` trait
+LL |     let mut count = 0;
+LL |     for await i in iter {
+   |     -------------------
+   |     |              |
+   |     |              value moved here
+   |     inside of this loop
+...
+LL |     for await i in iter {
+   |                    ^^^^ value used here after move
+   |
+help: consider cloning the value if the performance cost is acceptable
+   |
+LL |     for await i in iter.clone() {
+   |                        ++++++++
+help: borrow this binding in the pattern to avoid moving the value
+   |
+LL |     for await i in ref iter {
+   |                    +++
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0382`.
diff --git a/tests/ui/async-await/for-await-passthrough.rs b/tests/ui/async-await/for-await-passthrough.rs
new file mode 100644
index 00000000000..7fa133aaedc
--- /dev/null
+++ b/tests/ui/async-await/for-await-passthrough.rs
@@ -0,0 +1,32 @@
+// run-pass
+// edition: 2024
+// compile-flags: -Zunstable-options
+#![feature(async_iterator, async_iter_from_iter, const_waker, async_for_loop, noop_waker,
+           gen_blocks)]
+
+use std::future::Future;
+
+async gen fn async_iter() -> i32 {
+    let iter = core::async_iter::from_iter(0..3);
+    for await i in iter {
+        yield i + 1;
+    }
+}
+
+// make sure a simple for await loop works
+async fn real_main() {
+    let mut count = 1;
+    for await i in async_iter() {
+        assert_eq!(i, count);
+        count += 1;
+    }
+    assert_eq!(count, 4);
+}
+
+fn main() {
+    let future = real_main();
+    let waker = std::task::Waker::noop();
+    let mut cx = &mut core::task::Context::from_waker(&waker);
+    let mut future = core::pin::pin!(future);
+    while let core::task::Poll::Pending = future.as_mut().poll(&mut cx) {}
+}
-- 
cgit 1.4.1-3-g733a5


From 757d6f6ef8567ec846a62f16e3691b7555f2545f Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Tue, 19 Dec 2023 15:26:24 +1100
Subject: Give `DiagnosticBuilder` a default type.

`IntoDiagnostic` defaults to `ErrorGuaranteed`, because errors are the
most common diagnostic level. It makes sense to do likewise for the
closely-related (and much more widely used) `DiagnosticBuilder` type,
letting us write `DiagnosticBuilder<'a, ErrorGuaranteed>` as just
`DiagnosticBuilder<'a>`. This cuts over 200 lines of code due to many
multi-line things becoming single line things.
---
 compiler/rustc_borrowck/src/borrowck_errors.rs     |  56 +++++----
 .../src/diagnostics/bound_region_errors.rs         |  46 +++-----
 .../src/diagnostics/conflict_errors.rs             |  24 ++--
 .../rustc_borrowck/src/diagnostics/move_errors.rs  |   6 +-
 .../src/diagnostics/mutability_errors.rs           |  13 +--
 .../src/diagnostics/region_errors.rs               |  13 +--
 compiler/rustc_borrowck/src/lib.rs                 |  21 ++--
 compiler/rustc_builtin_macros/src/format.rs        |   6 +-
 .../src/transform/check_consts/ops.rs              | 128 ++++-----------------
 compiler/rustc_errors/src/diagnostic_builder.rs    |   4 +-
 compiler/rustc_errors/src/lib.rs                   |  18 +--
 compiler/rustc_expand/src/base.rs                  |   9 +-
 compiler/rustc_expand/src/mbe/diagnostics.rs       |   2 +-
 compiler/rustc_expand/src/mbe/transcribe.rs        |   4 +-
 compiler/rustc_expand/src/module.rs                |   2 +-
 compiler/rustc_hir_analysis/src/astconv/mod.rs     |   2 +-
 compiler/rustc_hir_analysis/src/check/wfcheck.rs   |   6 +-
 compiler/rustc_hir_analysis/src/collect.rs         |   4 +-
 .../rustc_hir_analysis/src/structured_errors.rs    |  16 +--
 .../missing_cast_for_variadic_arg.rs               |   9 +-
 .../src/structured_errors/sized_unsized_cast.rs    |   9 +-
 .../wrong_number_of_generic_args.rs                |   7 +-
 compiler/rustc_hir_typeck/src/cast.rs              |   2 +-
 compiler/rustc_hir_typeck/src/coercion.rs          |   6 +-
 compiler/rustc_hir_typeck/src/demand.rs            |  12 +-
 compiler/rustc_hir_typeck/src/expr.rs              |  10 +-
 compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs    |   2 +-
 compiler/rustc_hir_typeck/src/method/suggest.rs    |   9 +-
 compiler/rustc_hir_typeck/src/pat.rs               |  14 +--
 .../rustc_infer/src/infer/error_reporting/mod.rs   |   8 +-
 .../src/infer/error_reporting/need_type_info.rs    |   6 +-
 .../infer/error_reporting/nice_region_error/mod.rs |   2 +-
 .../nice_region_error/named_anon_conflict.rs       |   6 +-
 .../nice_region_error/placeholder_error.rs         |  10 +-
 .../nice_region_error/placeholder_relation.rs      |   6 +-
 .../rustc_infer/src/infer/error_reporting/note.rs  |   6 +-
 compiler/rustc_infer/src/infer/mod.rs              |   8 +-
 .../rustc_infer/src/traits/error_reporting/mod.rs  |   6 +-
 compiler/rustc_middle/src/mir/interpret/error.rs   |   5 +-
 compiler/rustc_middle/src/ty/mod.rs                |   2 +-
 compiler/rustc_mir_build/src/errors.rs             |   8 +-
 .../src/thir/pattern/check_match.rs                |   6 +-
 compiler/rustc_parse/src/errors.rs                 |  16 +--
 compiler/rustc_parse/src/parser/diagnostics.rs     |  21 ++--
 compiler/rustc_parse/src/parser/expr.rs            |   5 +-
 compiler/rustc_parse/src/parser/mod.rs             |   6 +-
 compiler/rustc_parse/src/parser/pat.rs             |   8 +-
 compiler/rustc_parse/src/parser/stmt.rs            |   4 +-
 compiler/rustc_query_system/src/query/job.rs       |   4 +-
 compiler/rustc_query_system/src/query/plumbing.rs  |   4 +-
 compiler/rustc_resolve/src/diagnostics.rs          |   2 +-
 compiler/rustc_resolve/src/late/diagnostics.rs     |   2 +-
 compiler/rustc_resolve/src/lib.rs                  |   4 +-
 compiler/rustc_session/src/errors.rs               |   9 +-
 compiler/rustc_session/src/parse.rs                |  14 +--
 compiler/rustc_session/src/session.rs              |  18 +--
 .../src/traits/error_reporting/infer_ctxt_ext.rs   |   6 +-
 .../src/traits/error_reporting/suggestions.rs      |  14 +--
 .../traits/error_reporting/type_err_ctxt_ext.rs    |  28 ++---
 59 files changed, 250 insertions(+), 454 deletions(-)

(limited to 'compiler/rustc_parse/src/parser/expr.rs')

diff --git a/compiler/rustc_borrowck/src/borrowck_errors.rs b/compiler/rustc_borrowck/src/borrowck_errors.rs
index 6731ef12306..e527a91eb6f 100644
--- a/compiler/rustc_borrowck/src/borrowck_errors.rs
+++ b/compiler/rustc_borrowck/src/borrowck_errors.rs
@@ -1,5 +1,5 @@
 use rustc_errors::{
-    struct_span_err, DiagnosticBuilder, DiagnosticId, DiagnosticMessage, ErrorGuaranteed, MultiSpan,
+    struct_span_err, DiagnosticBuilder, DiagnosticId, DiagnosticMessage, MultiSpan,
 };
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_span::Span;
@@ -12,7 +12,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         place: &str,
         borrow_place: &str,
         value_place: &str,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         self.infcx.tcx.sess.create_err(crate::session_diagnostics::MoveBorrow {
             place,
             span,
@@ -28,7 +28,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         desc: &str,
         borrow_span: Span,
         borrow_desc: &str,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let mut err = struct_span_err!(
             self,
             span,
@@ -50,7 +50,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         old_loan_span: Span,
         old_opt_via: &str,
         old_load_end_span: Option<Span>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let via = |msg: &str| if msg.is_empty() { "".to_string() } else { format!(" (via {msg})") };
         let mut err = struct_span_err!(
             self,
@@ -97,7 +97,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         desc: &str,
         old_loan_span: Span,
         old_load_end_span: Option<Span>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let mut err = struct_span_err!(
             self,
             new_loan_span,
@@ -130,7 +130,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         noun_old: &str,
         old_opt_via: &str,
         previous_end_span: Option<Span>,
-    ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'cx> {
         let mut err = struct_span_err!(
             self,
             new_loan_span,
@@ -162,7 +162,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         old_opt_via: &str,
         previous_end_span: Option<Span>,
         second_borrow_desc: &str,
-    ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'cx> {
         let mut err = struct_span_err!(
             self,
             new_loan_span,
@@ -194,7 +194,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         kind_old: &str,
         msg_old: &str,
         old_load_end_span: Option<Span>,
-    ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'cx> {
         let via = |msg: &str| if msg.is_empty() { "".to_string() } else { format!(" (via {msg})") };
         let mut err = struct_span_err!(
             self,
@@ -235,7 +235,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         span: Span,
         borrow_span: Span,
         desc: &str,
-    ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'cx> {
         let mut err = struct_span_err!(
             self,
             span,
@@ -254,16 +254,12 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         span: Span,
         desc: &str,
         is_arg: bool,
-    ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'cx> {
         let msg = if is_arg { "to immutable argument" } else { "twice to immutable variable" };
         struct_span_err!(self, span, E0384, "cannot assign {} {}", msg, desc)
     }
 
-    pub(crate) fn cannot_assign(
-        &self,
-        span: Span,
-        desc: &str,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    pub(crate) fn cannot_assign(&self, span: Span, desc: &str) -> DiagnosticBuilder<'tcx> {
         struct_span_err!(self, span, E0594, "cannot assign to {}", desc)
     }
 
@@ -271,7 +267,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         &self,
         move_from_span: Span,
         move_from_desc: &str,
-    ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'cx> {
         struct_span_err!(self, move_from_span, E0507, "cannot move out of {}", move_from_desc)
     }
 
@@ -283,7 +279,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         move_from_span: Span,
         ty: Ty<'_>,
         is_index: Option<bool>,
-    ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'cx> {
         let type_name = match (&ty.kind(), is_index) {
             (&ty::Array(_, _), Some(true)) | (&ty::Array(_, _), None) => "array",
             (&ty::Slice(_), _) => "slice",
@@ -305,7 +301,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         &self,
         move_from_span: Span,
         container_ty: Ty<'_>,
-    ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'cx> {
         let mut err = struct_span_err!(
             self,
             move_from_span,
@@ -323,7 +319,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         verb: &str,
         optional_adverb_for_moved: &str,
         moved_path: Option<String>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let moved_path = moved_path.map(|mp| format!(": `{mp}`")).unwrap_or_default();
 
         struct_span_err!(
@@ -342,7 +338,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         span: Span,
         path: &str,
         reason: &str,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         struct_span_err!(self, span, E0596, "cannot borrow {} as mutable{}", path, reason,)
     }
 
@@ -353,7 +349,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         immutable_place: &str,
         immutable_section: &str,
         action: &str,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let mut err = struct_span_err!(
             self,
             mutate_span,
@@ -372,7 +368,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         &self,
         span: Span,
         yield_span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let coroutine_kind = self.body.coroutine.as_ref().unwrap().coroutine_kind;
         let mut err = struct_span_err!(
             self,
@@ -387,7 +383,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
     pub(crate) fn cannot_borrow_across_destructor(
         &self,
         borrow_span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         struct_span_err!(
             self,
             borrow_span,
@@ -400,7 +396,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         &self,
         span: Span,
         path: &str,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         struct_span_err!(self, span, E0597, "{} does not live long enough", path,)
     }
 
@@ -410,7 +406,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         return_kind: &str,
         reference_desc: &str,
         path_desc: &str,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let mut err = struct_span_err!(
             self,
             span,
@@ -436,7 +432,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         borrowed_path: &str,
         capture_span: Span,
         scope: &str,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let mut err = struct_span_err!(
             self,
             closure_span,
@@ -452,14 +448,14 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
     pub(crate) fn thread_local_value_does_not_live_long_enough(
         &self,
         span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         struct_span_err!(self, span, E0712, "thread-local variable borrowed past end of function",)
     }
 
     pub(crate) fn temporary_value_borrowed_for_too_long(
         &self,
         span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         struct_span_err!(self, span, E0716, "temporary value dropped while borrowed",)
     }
 
@@ -470,7 +466,7 @@ impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
         sp: S,
         msg: impl Into<DiagnosticMessage>,
         code: DiagnosticId,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         self.infcx.tcx.sess.struct_span_err_with_code(sp, msg, code)
     }
 }
@@ -479,7 +475,7 @@ pub(crate) fn borrowed_data_escapes_closure<'tcx>(
     tcx: TyCtxt<'tcx>,
     escape_span: Span,
     escapes_from: &str,
-) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+) -> DiagnosticBuilder<'tcx> {
     struct_span_err!(
         tcx.sess,
         escape_span,
diff --git a/compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs b/compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs
index 60dbf7dc055..e6881316a8f 100644
--- a/compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs
@@ -1,7 +1,7 @@
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
 
-use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed};
+use rustc_errors::DiagnosticBuilder;
 use rustc_infer::infer::canonical::Canonical;
 use rustc_infer::infer::error_reporting::nice_region_error::NiceRegionError;
 use rustc_infer::infer::region_constraints::Constraint;
@@ -147,11 +147,7 @@ impl<'tcx> ToUniverseInfo<'tcx> for ! {
 trait TypeOpInfo<'tcx> {
     /// Returns an error to be reported if rerunning the type op fails to
     /// recover the error's cause.
-    fn fallback_error(
-        &self,
-        tcx: TyCtxt<'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>;
+    fn fallback_error(&self, tcx: TyCtxt<'tcx>, span: Span) -> DiagnosticBuilder<'tcx>;
 
     fn base_universe(&self) -> ty::UniverseIndex;
 
@@ -161,7 +157,7 @@ trait TypeOpInfo<'tcx> {
         cause: ObligationCause<'tcx>,
         placeholder_region: ty::Region<'tcx>,
         error_region: Option<ty::Region<'tcx>>,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>>;
+    ) -> Option<DiagnosticBuilder<'tcx>>;
 
     #[instrument(level = "debug", skip(self, mbcx))]
     fn report_error(
@@ -224,11 +220,7 @@ struct PredicateQuery<'tcx> {
 }
 
 impl<'tcx> TypeOpInfo<'tcx> for PredicateQuery<'tcx> {
-    fn fallback_error(
-        &self,
-        tcx: TyCtxt<'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn fallback_error(&self, tcx: TyCtxt<'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         tcx.sess.create_err(HigherRankedLifetimeError {
             cause: Some(HigherRankedErrorCause::CouldNotProve {
                 predicate: self.canonical_query.value.value.predicate.to_string(),
@@ -247,7 +239,7 @@ impl<'tcx> TypeOpInfo<'tcx> for PredicateQuery<'tcx> {
         cause: ObligationCause<'tcx>,
         placeholder_region: ty::Region<'tcx>,
         error_region: Option<ty::Region<'tcx>>,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'tcx>> {
         let (infcx, key, _) =
             mbcx.infcx.tcx.infer_ctxt().build_with_canonical(cause.span, &self.canonical_query);
         let ocx = ObligationCtxt::new(&infcx);
@@ -265,11 +257,7 @@ impl<'tcx, T> TypeOpInfo<'tcx> for NormalizeQuery<'tcx, T>
 where
     T: Copy + fmt::Display + TypeFoldable<TyCtxt<'tcx>> + 'tcx,
 {
-    fn fallback_error(
-        &self,
-        tcx: TyCtxt<'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn fallback_error(&self, tcx: TyCtxt<'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         tcx.sess.create_err(HigherRankedLifetimeError {
             cause: Some(HigherRankedErrorCause::CouldNotNormalize {
                 value: self.canonical_query.value.value.value.to_string(),
@@ -288,7 +276,7 @@ where
         cause: ObligationCause<'tcx>,
         placeholder_region: ty::Region<'tcx>,
         error_region: Option<ty::Region<'tcx>>,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'tcx>> {
         let (infcx, key, _) =
             mbcx.infcx.tcx.infer_ctxt().build_with_canonical(cause.span, &self.canonical_query);
         let ocx = ObligationCtxt::new(&infcx);
@@ -312,11 +300,7 @@ struct AscribeUserTypeQuery<'tcx> {
 }
 
 impl<'tcx> TypeOpInfo<'tcx> for AscribeUserTypeQuery<'tcx> {
-    fn fallback_error(
-        &self,
-        tcx: TyCtxt<'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn fallback_error(&self, tcx: TyCtxt<'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         // FIXME: This error message isn't great, but it doesn't show up in the existing UI tests,
         // and is only the fallback when the nice error fails. Consider improving this some more.
         tcx.sess.create_err(HigherRankedLifetimeError { cause: None, span })
@@ -332,7 +316,7 @@ impl<'tcx> TypeOpInfo<'tcx> for AscribeUserTypeQuery<'tcx> {
         cause: ObligationCause<'tcx>,
         placeholder_region: ty::Region<'tcx>,
         error_region: Option<ty::Region<'tcx>>,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'tcx>> {
         let (infcx, key, _) =
             mbcx.infcx.tcx.infer_ctxt().build_with_canonical(cause.span, &self.canonical_query);
         let ocx = ObligationCtxt::new(&infcx);
@@ -342,11 +326,7 @@ impl<'tcx> TypeOpInfo<'tcx> for AscribeUserTypeQuery<'tcx> {
 }
 
 impl<'tcx> TypeOpInfo<'tcx> for crate::type_check::InstantiateOpaqueType<'tcx> {
-    fn fallback_error(
-        &self,
-        tcx: TyCtxt<'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn fallback_error(&self, tcx: TyCtxt<'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         // FIXME: This error message isn't great, but it doesn't show up in the existing UI tests,
         // and is only the fallback when the nice error fails. Consider improving this some more.
         tcx.sess.create_err(HigherRankedLifetimeError { cause: None, span })
@@ -362,7 +342,7 @@ impl<'tcx> TypeOpInfo<'tcx> for crate::type_check::InstantiateOpaqueType<'tcx> {
         _cause: ObligationCause<'tcx>,
         placeholder_region: ty::Region<'tcx>,
         error_region: Option<ty::Region<'tcx>>,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'tcx>> {
         try_extract_error_from_region_constraints(
             mbcx.infcx,
             placeholder_region,
@@ -383,7 +363,7 @@ fn try_extract_error_from_fulfill_cx<'tcx>(
     ocx: &ObligationCtxt<'_, 'tcx>,
     placeholder_region: ty::Region<'tcx>,
     error_region: Option<ty::Region<'tcx>>,
-) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+) -> Option<DiagnosticBuilder<'tcx>> {
     // We generally shouldn't have errors here because the query was
     // already run, but there's no point using `span_delayed_bug`
     // when we're going to emit an error here anyway.
@@ -407,7 +387,7 @@ fn try_extract_error_from_region_constraints<'tcx>(
     region_constraints: &RegionConstraintData<'tcx>,
     mut region_var_origin: impl FnMut(RegionVid) -> RegionVariableOrigin,
     mut universe_of_region: impl FnMut(RegionVid) -> UniverseIndex,
-) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+) -> Option<DiagnosticBuilder<'tcx>> {
     let placeholder_universe = match placeholder_region.kind() {
         ty::RePlaceholder(p) => p.universe,
         ty::ReVar(vid) => universe_of_region(vid),
diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
index db0f4559a6b..bd548fd131a 100644
--- a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -2,9 +2,7 @@ use either::Either;
 use hir::PatField;
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxIndexSet;
-use rustc_errors::{
-    struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, MultiSpan,
-};
+use rustc_errors::{struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::intravisit::{walk_block, walk_expr, Visitor};
@@ -324,7 +322,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         &mut self,
         mpi: MovePathIndex,
         move_span: Span,
-        err: &mut DiagnosticBuilder<'_, ErrorGuaranteed>,
+        err: &mut DiagnosticBuilder<'_>,
         in_pattern: &mut bool,
         move_spans: UseSpans<'_>,
     ) {
@@ -483,7 +481,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         desired_action: InitializationRequiringAction,
         span: Span,
         use_spans: UseSpans<'tcx>,
-    ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'cx> {
         // We need all statements in the body where the binding was assigned to to later find all
         // the branching code paths where the binding *wasn't* assigned to.
         let inits = &self.move_data.init_path_map[mpi];
@@ -873,7 +871,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         location: Location,
         (place, _span): (Place<'tcx>, Span),
         borrow: &BorrowData<'tcx>,
-    ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'cx> {
         let borrow_spans = self.retrieve_borrow_spans(borrow);
         let borrow_span = borrow_spans.args_or_use();
 
@@ -921,7 +919,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         (place, span): (Place<'tcx>, Span),
         gen_borrow_kind: BorrowKind,
         issued_borrow: &BorrowData<'tcx>,
-    ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'cx> {
         let issued_spans = self.retrieve_borrow_spans(issued_borrow);
         let issued_span = issued_spans.args_or_use();
 
@@ -2025,7 +2023,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         drop_span: Span,
         borrow_spans: UseSpans<'tcx>,
         explanation: BorrowExplanation<'tcx>,
-    ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'cx> {
         debug!(
             "report_local_value_does_not_live_long_enough(\
              {:?}, {:?}, {:?}, {:?}, {:?}\
@@ -2200,7 +2198,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         &mut self,
         drop_span: Span,
         borrow_span: Span,
-    ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'cx> {
         debug!(
             "report_thread_local_value_does_not_live_long_enough(\
              {:?}, {:?}\
@@ -2228,7 +2226,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         borrow_spans: UseSpans<'tcx>,
         proper_span: Span,
         explanation: BorrowExplanation<'tcx>,
-    ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'cx> {
         if let BorrowExplanation::MustBeValidFor { category, span, from_closure: false, .. } =
             explanation
         {
@@ -2395,7 +2393,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         return_span: Span,
         category: ConstraintCategory<'tcx>,
         opt_place_desc: Option<&String>,
-    ) -> Option<DiagnosticBuilder<'cx, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'cx>> {
         let return_kind = match category {
             ConstraintCategory::Return(_) => "return",
             ConstraintCategory::Yield => "yield",
@@ -2490,7 +2488,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         constraint_span: Span,
         captured_var: &str,
         scope: &str,
-    ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'cx> {
         let tcx = self.infcx.tcx;
         let args_span = use_span.args_or_use();
 
@@ -2593,7 +2591,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         upvar_span: Span,
         upvar_name: Symbol,
         escape_span: Span,
-    ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'cx> {
         let tcx = self.infcx.tcx;
 
         let escapes_from = tcx.def_descr(self.mir_def_id().to_def_id());
diff --git a/compiler/rustc_borrowck/src/diagnostics/move_errors.rs b/compiler/rustc_borrowck/src/diagnostics/move_errors.rs
index 43487b85a7b..f3b21d22c1a 100644
--- a/compiler/rustc_borrowck/src/diagnostics/move_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/move_errors.rs
@@ -1,4 +1,4 @@
-use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed};
+use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder};
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, Ty};
 use rustc_mir_dataflow::move_paths::{LookupResult, MovePathIndex};
@@ -288,7 +288,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         &mut self,
         place: Place<'tcx>,
         span: Span,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'a> {
         let description = if place.projection.len() == 1 {
             format!("static item {}", self.describe_any_place(place.as_ref()))
         } else {
@@ -310,7 +310,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         deref_target_place: Place<'tcx>,
         span: Span,
         use_spans: Option<UseSpans<'tcx>>,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'a> {
         // Inspect the type of the content behind the
         // borrow to provide feedback about why this
         // was a move rather than a copy.
diff --git a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
index c3c1f1293d2..506933c470e 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
@@ -1,5 +1,5 @@
 use hir::ExprKind;
-use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed};
+use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder};
 use rustc_hir as hir;
 use rustc_hir::intravisit::Visitor;
 use rustc_hir::Node;
@@ -711,7 +711,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
 
     fn construct_mut_suggestion_for_local_binding_patterns(
         &self,
-        err: &mut DiagnosticBuilder<'_, ErrorGuaranteed>,
+        err: &mut DiagnosticBuilder<'_>,
         local: Local,
     ) {
         let local_decl = &self.body.local_decls[local];
@@ -1025,7 +1025,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         }
     }
 
-    fn suggest_using_iter_mut(&self, err: &mut DiagnosticBuilder<'_, ErrorGuaranteed>) {
+    fn suggest_using_iter_mut(&self, err: &mut DiagnosticBuilder<'_>) {
         let source = self.body.source;
         let hir = self.infcx.tcx.hir();
         if let InstanceDef::Item(def_id) = source.instance
@@ -1067,12 +1067,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         }
     }
 
-    fn suggest_make_local_mut(
-        &self,
-        err: &mut DiagnosticBuilder<'_, ErrorGuaranteed>,
-        local: Local,
-        name: Symbol,
-    ) {
+    fn suggest_make_local_mut(&self, err: &mut DiagnosticBuilder<'_>, local: Local, name: Symbol) {
         let local_decl = &self.body.local_decls[local];
 
         let (pointer_sigil, pointer_desc) =
diff --git a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
index 759f5e910f7..e967d9f70ce 100644
--- a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
@@ -3,7 +3,7 @@
 //! Error reporting machinery for lifetime errors.
 
 use rustc_data_structures::fx::FxIndexSet;
-use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, MultiSpan};
+use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::def::Res::Def;
 use rustc_hir::def_id::DefId;
@@ -202,7 +202,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
     // and the span which bounded to the trait for adding 'static lifetime suggestion
     fn suggest_static_lifetime_for_gat_from_hrtb(
         &self,
-        diag: &mut DiagnosticBuilder<'_, ErrorGuaranteed>,
+        diag: &mut DiagnosticBuilder<'_>,
         lower_bound: RegionVid,
     ) {
         let mut suggestions = vec![];
@@ -573,7 +573,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         &self,
         errci: &ErrorConstraintInfo<'tcx>,
         kind: ReturnConstraint,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let ErrorConstraintInfo { outlived_fr, span, .. } = errci;
 
         let mut output_ty = self.regioncx.universal_regions().unnormalized_output_ty;
@@ -645,7 +645,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
     fn report_escaping_data_error(
         &self,
         errci: &ErrorConstraintInfo<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let ErrorConstraintInfo { span, category, .. } = errci;
 
         let fr_name_and_span = self.regioncx.get_var_name_and_span_for_region(
@@ -744,10 +744,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
     ///    |     ^^^^^^^^^^^^^^ function was supposed to return data with lifetime `'a` but it
     ///    |                    is returning data with lifetime `'b`
     /// ```
-    fn report_general_error(
-        &self,
-        errci: &ErrorConstraintInfo<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn report_general_error(&self, errci: &ErrorConstraintInfo<'tcx>) -> DiagnosticBuilder<'tcx> {
         let ErrorConstraintInfo {
             fr,
             fr_is_local,
diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs
index 43f48f579a3..cf2d2ca7465 100644
--- a/compiler/rustc_borrowck/src/lib.rs
+++ b/compiler/rustc_borrowck/src/lib.rs
@@ -2407,8 +2407,8 @@ mod error {
         /// when errors in the map are being re-added to the error buffer so that errors with the
         /// same primary span come out in a consistent order.
         buffered_move_errors:
-            BTreeMap<Vec<MoveOutIndex>, (PlaceRef<'tcx>, DiagnosticBuilder<'tcx, ErrorGuaranteed>)>,
-        buffered_mut_errors: FxIndexMap<Span, (DiagnosticBuilder<'tcx, ErrorGuaranteed>, usize)>,
+            BTreeMap<Vec<MoveOutIndex>, (PlaceRef<'tcx>, DiagnosticBuilder<'tcx>)>,
+        buffered_mut_errors: FxIndexMap<Span, (DiagnosticBuilder<'tcx>, usize)>,
         /// Diagnostics to be reported buffer.
         buffered: Vec<Diagnostic>,
         /// Set to Some if we emit an error during borrowck
@@ -2426,7 +2426,7 @@ mod error {
             }
         }
 
-        pub fn buffer_error(&mut self, t: DiagnosticBuilder<'_, ErrorGuaranteed>) {
+        pub fn buffer_error(&mut self, t: DiagnosticBuilder<'_>) {
             if let None = self.tainted_by_errors {
                 self.tainted_by_errors = Some(self.tcx.sess.span_delayed_bug(
                     t.span.clone_ignoring_labels(),
@@ -2446,7 +2446,7 @@ mod error {
     }
 
     impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
-        pub fn buffer_error(&mut self, t: DiagnosticBuilder<'_, ErrorGuaranteed>) {
+        pub fn buffer_error(&mut self, t: DiagnosticBuilder<'_>) {
             self.errors.buffer_error(t);
         }
 
@@ -2457,7 +2457,7 @@ mod error {
         pub fn buffer_move_error(
             &mut self,
             move_out_indices: Vec<MoveOutIndex>,
-            place_and_err: (PlaceRef<'tcx>, DiagnosticBuilder<'tcx, ErrorGuaranteed>),
+            place_and_err: (PlaceRef<'tcx>, DiagnosticBuilder<'tcx>),
         ) -> bool {
             if let Some((_, diag)) =
                 self.errors.buffered_move_errors.insert(move_out_indices, place_and_err)
@@ -2473,16 +2473,11 @@ mod error {
         pub fn get_buffered_mut_error(
             &mut self,
             span: Span,
-        ) -> Option<(DiagnosticBuilder<'tcx, ErrorGuaranteed>, usize)> {
+        ) -> Option<(DiagnosticBuilder<'tcx>, usize)> {
             self.errors.buffered_mut_errors.remove(&span)
         }
 
-        pub fn buffer_mut_error(
-            &mut self,
-            span: Span,
-            t: DiagnosticBuilder<'tcx, ErrorGuaranteed>,
-            count: usize,
-        ) {
+        pub fn buffer_mut_error(&mut self, span: Span, t: DiagnosticBuilder<'tcx>, count: usize) {
             self.errors.buffered_mut_errors.insert(span, (t, count));
         }
 
@@ -2517,7 +2512,7 @@ mod error {
         pub fn has_move_error(
             &self,
             move_out_indices: &[MoveOutIndex],
-        ) -> Option<&(PlaceRef<'tcx>, DiagnosticBuilder<'cx, ErrorGuaranteed>)> {
+        ) -> Option<&(PlaceRef<'tcx>, DiagnosticBuilder<'cx>)> {
             self.errors.buffered_move_errors.get(move_out_indices)
         }
     }
diff --git a/compiler/rustc_builtin_macros/src/format.rs b/compiler/rustc_builtin_macros/src/format.rs
index c5fd535b036..58e18825ed6 100644
--- a/compiler/rustc_builtin_macros/src/format.rs
+++ b/compiler/rustc_builtin_macros/src/format.rs
@@ -8,9 +8,7 @@ use rustc_ast::{
     FormatDebugHex, FormatOptions, FormatPlaceholder, FormatSign, FormatTrait,
 };
 use rustc_data_structures::fx::FxHashSet;
-use rustc_errors::{
-    Applicability, DiagnosticBuilder, ErrorGuaranteed, MultiSpan, PResult, SingleLabelManySpans,
-};
+use rustc_errors::{Applicability, DiagnosticBuilder, MultiSpan, PResult, SingleLabelManySpans};
 use rustc_expand::base::{self, *};
 use rustc_parse_format as parse;
 use rustc_span::symbol::{Ident, Symbol};
@@ -726,7 +724,7 @@ fn report_redundant_format_arguments<'a>(
     args: &FormatArguments,
     used: &[bool],
     placeholders: Vec<(Span, &str)>,
-) -> Option<DiagnosticBuilder<'a, ErrorGuaranteed>> {
+) -> Option<DiagnosticBuilder<'a>> {
     let mut fmt_arg_indices = vec![];
     let mut args_spans = vec![];
     let mut fmt_spans = vec![];
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/ops.rs b/compiler/rustc_const_eval/src/transform/check_consts/ops.rs
index 2de6362b9fe..56cb23f9751 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/ops.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/ops.rs
@@ -2,7 +2,7 @@
 
 use hir::def_id::LocalDefId;
 use hir::{ConstContext, LangItem};
-use rustc_errors::{error_code, DiagnosticBuilder, ErrorGuaranteed};
+use rustc_errors::{error_code, DiagnosticBuilder};
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_infer::infer::TyCtxtInferExt;
@@ -48,11 +48,7 @@ pub trait NonConstOp<'tcx>: std::fmt::Debug {
         DiagnosticImportance::Primary
     }
 
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>;
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx>;
 }
 
 #[derive(Debug)]
@@ -66,11 +62,7 @@ impl<'tcx> NonConstOp<'tcx> for FloatingPointOp {
         }
     }
 
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         feature_err(
             &ccx.tcx.sess.parse_sess,
             sym::const_fn_floating_point_arithmetic,
@@ -84,11 +76,7 @@ impl<'tcx> NonConstOp<'tcx> for FloatingPointOp {
 #[derive(Debug)]
 pub struct FnCallIndirect;
 impl<'tcx> NonConstOp<'tcx> for FnCallIndirect {
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         ccx.tcx.sess.create_err(errors::UnallowedFnPointerCall { span, kind: ccx.const_kind() })
     }
 }
@@ -105,11 +93,7 @@ pub struct FnCallNonConst<'tcx> {
 }
 
 impl<'tcx> NonConstOp<'tcx> for FnCallNonConst<'tcx> {
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        _: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, _: Span) -> DiagnosticBuilder<'tcx> {
         let FnCallNonConst { caller, callee, args, span, call_source, feature } = *self;
         let ConstCx { tcx, param_env, .. } = *ccx;
 
@@ -331,11 +315,7 @@ impl<'tcx> NonConstOp<'tcx> for FnCallNonConst<'tcx> {
 pub struct FnCallUnstable(pub DefId, pub Option<Symbol>);
 
 impl<'tcx> NonConstOp<'tcx> for FnCallUnstable {
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         let FnCallUnstable(def_id, feature) = *self;
 
         let mut err = ccx
@@ -366,11 +346,7 @@ impl<'tcx> NonConstOp<'tcx> for Coroutine {
         }
     }
 
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         let msg = format!("{:#}s are not allowed in {}s", self.0, ccx.const_kind());
         if let hir::CoroutineKind::Async(hir::CoroutineSource::Block) = self.0 {
             ccx.tcx.sess.create_feature_err(
@@ -386,11 +362,7 @@ impl<'tcx> NonConstOp<'tcx> for Coroutine {
 #[derive(Debug)]
 pub struct HeapAllocation;
 impl<'tcx> NonConstOp<'tcx> for HeapAllocation {
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         ccx.tcx.sess.create_err(errors::UnallowedHeapAllocations {
             span,
             kind: ccx.const_kind(),
@@ -402,11 +374,7 @@ impl<'tcx> NonConstOp<'tcx> for HeapAllocation {
 #[derive(Debug)]
 pub struct InlineAsm;
 impl<'tcx> NonConstOp<'tcx> for InlineAsm {
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         ccx.tcx.sess.create_err(errors::UnallowedInlineAsm { span, kind: ccx.const_kind() })
     }
 }
@@ -417,11 +385,7 @@ pub struct LiveDrop<'tcx> {
     pub dropped_ty: Ty<'tcx>,
 }
 impl<'tcx> NonConstOp<'tcx> for LiveDrop<'tcx> {
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         ccx.tcx.sess.create_err(errors::LiveDrop {
             span,
             dropped_ty: self.dropped_ty,
@@ -444,11 +408,7 @@ impl<'tcx> NonConstOp<'tcx> for TransientCellBorrow {
         // not additionally emit a feature gate error if activating the feature gate won't work.
         DiagnosticImportance::Secondary
     }
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         ccx.tcx
             .sess
             .create_feature_err(errors::InteriorMutabilityBorrow { span }, sym::const_refs_to_cell)
@@ -461,11 +421,7 @@ impl<'tcx> NonConstOp<'tcx> for TransientCellBorrow {
 /// it in the future for static items.
 pub struct CellBorrow;
 impl<'tcx> NonConstOp<'tcx> for CellBorrow {
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         // FIXME: Maybe a more elegant solution to this if else case
         if let hir::ConstContext::Static(_) = ccx.const_kind() {
             ccx.tcx.sess.create_err(errors::InteriorMutableDataRefer {
@@ -502,11 +458,7 @@ impl<'tcx> NonConstOp<'tcx> for MutBorrow {
         DiagnosticImportance::Secondary
     }
 
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         match self.0 {
             hir::BorrowKind::Raw => ccx.tcx.sess.create_err(errors::UnallowedMutableRefsRaw {
                 span,
@@ -530,11 +482,7 @@ impl<'tcx> NonConstOp<'tcx> for TransientMutBorrow {
         Status::Unstable(sym::const_mut_refs)
     }
 
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         let kind = ccx.const_kind();
         match self.0 {
             hir::BorrowKind::Raw => ccx.tcx.sess.create_feature_err(
@@ -561,11 +509,7 @@ impl<'tcx> NonConstOp<'tcx> for MutDeref {
         DiagnosticImportance::Secondary
     }
 
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         ccx.tcx.sess.create_feature_err(
             errors::MutDerefErr { span, kind: ccx.const_kind() },
             sym::const_mut_refs,
@@ -577,11 +521,7 @@ impl<'tcx> NonConstOp<'tcx> for MutDeref {
 #[derive(Debug)]
 pub struct PanicNonStr;
 impl<'tcx> NonConstOp<'tcx> for PanicNonStr {
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         ccx.tcx.sess.create_err(errors::PanicNonStrErr { span })
     }
 }
@@ -592,11 +532,7 @@ impl<'tcx> NonConstOp<'tcx> for PanicNonStr {
 #[derive(Debug)]
 pub struct RawPtrComparison;
 impl<'tcx> NonConstOp<'tcx> for RawPtrComparison {
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         // FIXME(const_trait_impl): revert to span_bug?
         ccx.tcx.sess.create_err(errors::RawPtrComparisonErr { span })
     }
@@ -609,11 +545,7 @@ impl<'tcx> NonConstOp<'tcx> for RawMutPtrDeref {
         Status::Unstable(sym::const_mut_refs)
     }
 
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         feature_err(
             &ccx.tcx.sess.parse_sess,
             sym::const_mut_refs,
@@ -629,11 +561,7 @@ impl<'tcx> NonConstOp<'tcx> for RawMutPtrDeref {
 #[derive(Debug)]
 pub struct RawPtrToIntCast;
 impl<'tcx> NonConstOp<'tcx> for RawPtrToIntCast {
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         ccx.tcx.sess.create_err(errors::RawPtrToIntErr { span })
     }
 }
@@ -650,11 +578,7 @@ impl<'tcx> NonConstOp<'tcx> for StaticAccess {
         }
     }
 
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         ccx.tcx.sess.create_err(errors::StaticAccessErr {
             span,
             kind: ccx.const_kind(),
@@ -667,11 +591,7 @@ impl<'tcx> NonConstOp<'tcx> for StaticAccess {
 #[derive(Debug)]
 pub struct ThreadLocalAccess;
 impl<'tcx> NonConstOp<'tcx> for ThreadLocalAccess {
-    fn build_error(
-        &self,
-        ccx: &ConstCx<'_, 'tcx>,
-        span: Span,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
         ccx.tcx.sess.create_err(errors::NonConstOpErr { span })
     }
 }
@@ -696,11 +616,7 @@ pub mod ty {
             }
         }
 
-        fn build_error(
-            &self,
-            ccx: &ConstCx<'_, 'tcx>,
-            span: Span,
-        ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+        fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
             feature_err(
                 &ccx.tcx.sess.parse_sess,
                 sym::const_mut_refs,
diff --git a/compiler/rustc_errors/src/diagnostic_builder.rs b/compiler/rustc_errors/src/diagnostic_builder.rs
index 828560ec452..e8cad62f393 100644
--- a/compiler/rustc_errors/src/diagnostic_builder.rs
+++ b/compiler/rustc_errors/src/diagnostic_builder.rs
@@ -43,7 +43,7 @@ where
 /// extending `DiagCtxtFlags`.
 #[must_use]
 #[derive(Clone)]
-pub struct DiagnosticBuilder<'a, G: EmissionGuarantee> {
+pub struct DiagnosticBuilder<'a, G: EmissionGuarantee = ErrorGuaranteed> {
     inner: DiagnosticBuilderInner<'a>,
     _marker: PhantomData<G>,
 }
@@ -128,7 +128,7 @@ impl<'a, G: EmissionGuarantee> DiagnosticBuilder<'a, G> {
     }
 }
 
-impl<'a> DiagnosticBuilder<'a, ErrorGuaranteed> {
+impl<'a> DiagnosticBuilder<'a> {
     /// Discard the guarantee `.emit()` would return, in favor of having the
     /// type `DiagnosticBuilder<'a, ()>`. This may be necessary whenever there
     /// is a common codepath handling both errors and warnings.
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index dafb67932a0..c48fe1ca8c2 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -91,7 +91,7 @@ mod styled_buffer;
 mod tests;
 pub mod translation;
 
-pub type PErr<'a> = DiagnosticBuilder<'a, ErrorGuaranteed>;
+pub type PErr<'a> = DiagnosticBuilder<'a>;
 pub type PResult<'a, T> = Result<T, PErr<'a>>;
 
 rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
@@ -788,7 +788,7 @@ impl DiagCtxt {
         &self,
         span: impl Into<MultiSpan>,
         msg: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'_> {
         let mut result = self.struct_err(msg);
         result.set_span(span);
         result
@@ -802,7 +802,7 @@ impl DiagCtxt {
         span: impl Into<MultiSpan>,
         msg: impl Into<DiagnosticMessage>,
         code: DiagnosticId,
-    ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'_> {
         let mut result = self.struct_span_err(span, msg);
         result.code(code);
         result
@@ -812,10 +812,7 @@ impl DiagCtxt {
     // FIXME: This method should be removed (every error should have an associated error code).
     #[rustc_lint_diagnostics]
     #[track_caller]
-    pub fn struct_err(
-        &self,
-        msg: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+    pub fn struct_err(&self, msg: impl Into<DiagnosticMessage>) -> DiagnosticBuilder<'_> {
         DiagnosticBuilder::new(self, Level::Error { lint: false }, msg)
     }
 
@@ -826,7 +823,7 @@ impl DiagCtxt {
         &self,
         msg: impl Into<DiagnosticMessage>,
         code: DiagnosticId,
-    ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'_> {
         let mut result = self.struct_err(msg);
         result.code(code);
         result
@@ -1221,10 +1218,7 @@ impl DiagCtxt {
     }
 
     #[track_caller]
-    pub fn create_err<'a>(
-        &'a self,
-        err: impl IntoDiagnostic<'a>,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    pub fn create_err<'a>(&'a self, err: impl IntoDiagnostic<'a>) -> DiagnosticBuilder<'a> {
         err.into_diagnostic(self, Level::Error { lint: false })
     }
 
diff --git a/compiler/rustc_expand/src/base.rs b/compiler/rustc_expand/src/base.rs
index ee0b10edfda..1fd4d2d55dd 100644
--- a/compiler/rustc_expand/src/base.rs
+++ b/compiler/rustc_expand/src/base.rs
@@ -1118,15 +1118,12 @@ impl<'a> ExtCtxt<'a> {
         &self,
         sp: S,
         msg: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'a> {
         self.sess.dcx().struct_span_err(sp, msg)
     }
 
     #[track_caller]
-    pub fn create_err(
-        &self,
-        err: impl IntoDiagnostic<'a>,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    pub fn create_err(&self, err: impl IntoDiagnostic<'a>) -> DiagnosticBuilder<'a> {
         self.sess.create_err(err)
     }
 
@@ -1230,7 +1227,7 @@ pub fn expr_to_spanned_string<'a>(
     cx: &'a mut ExtCtxt<'_>,
     expr: P<ast::Expr>,
     err_msg: &'static str,
-) -> Result<(Symbol, ast::StrStyle, Span), Option<(DiagnosticBuilder<'a, ErrorGuaranteed>, bool)>> {
+) -> Result<(Symbol, ast::StrStyle, Span), Option<(DiagnosticBuilder<'a>, bool)>> {
     // Perform eager expansion on the expression.
     // We want to be able to handle e.g., `concat!("foo", "bar")`.
     let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
diff --git a/compiler/rustc_expand/src/mbe/diagnostics.rs b/compiler/rustc_expand/src/mbe/diagnostics.rs
index 8f80e6e2927..cda3fa30a5b 100644
--- a/compiler/rustc_expand/src/mbe/diagnostics.rs
+++ b/compiler/rustc_expand/src/mbe/diagnostics.rs
@@ -215,7 +215,7 @@ impl<'matcher> Tracker<'matcher> for FailureForwarder {
 }
 
 pub(super) fn emit_frag_parse_err(
-    mut e: DiagnosticBuilder<'_, rustc_errors::ErrorGuaranteed>,
+    mut e: DiagnosticBuilder<'_>,
     parser: &Parser<'_>,
     orig_parser: &mut Parser<'_>,
     site_span: Span,
diff --git a/compiler/rustc_expand/src/mbe/transcribe.rs b/compiler/rustc_expand/src/mbe/transcribe.rs
index 80fd82e0302..ac5f3fb325d 100644
--- a/compiler/rustc_expand/src/mbe/transcribe.rs
+++ b/compiler/rustc_expand/src/mbe/transcribe.rs
@@ -9,8 +9,8 @@ use rustc_ast::mut_visit::{self, MutVisitor};
 use rustc_ast::token::{self, Delimiter, Token, TokenKind};
 use rustc_ast::tokenstream::{DelimSpacing, DelimSpan, Spacing, TokenStream, TokenTree};
 use rustc_data_structures::fx::FxHashMap;
+use rustc_errors::DiagnosticBuilder;
 use rustc_errors::{pluralize, PResult};
-use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed};
 use rustc_span::hygiene::{LocalExpnId, Transparency};
 use rustc_span::symbol::{sym, Ident, MacroRulesNormalizedIdent};
 use rustc_span::Span;
@@ -528,7 +528,7 @@ fn out_of_bounds_err<'a>(
     max: usize,
     span: Span,
     ty: &str,
-) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+) -> DiagnosticBuilder<'a> {
     let msg = if max == 0 {
         format!(
             "meta-variable expression `{ty}` with depth parameter \
diff --git a/compiler/rustc_expand/src/module.rs b/compiler/rustc_expand/src/module.rs
index a0dec89d631..cd59ea9092c 100644
--- a/compiler/rustc_expand/src/module.rs
+++ b/compiler/rustc_expand/src/module.rs
@@ -43,7 +43,7 @@ pub enum ModError<'a> {
     ModInBlock(Option<Ident>),
     FileNotFound(Ident, PathBuf, PathBuf),
     MultipleCandidates(Ident, PathBuf, PathBuf),
-    ParserError(DiagnosticBuilder<'a, ErrorGuaranteed>),
+    ParserError(DiagnosticBuilder<'a>),
 }
 
 pub(crate) fn parse_external_mod(
diff --git a/compiler/rustc_hir_analysis/src/astconv/mod.rs b/compiler/rustc_hir_analysis/src/astconv/mod.rs
index 6f8e80172dd..d1f99f3b799 100644
--- a/compiler/rustc_hir_analysis/src/astconv/mod.rs
+++ b/compiler/rustc_hir_analysis/src/astconv/mod.rs
@@ -2686,7 +2686,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         &self,
         constrained_regions: FxHashSet<ty::BoundRegionKind>,
         referenced_regions: FxHashSet<ty::BoundRegionKind>,
-        generate_err: impl Fn(&str) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>,
+        generate_err: impl Fn(&str) -> DiagnosticBuilder<'tcx>,
     ) {
         for br in referenced_regions.difference(&constrained_regions) {
             let br_name = match *br {
diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
index b2ff7959106..cc34dbfd9b9 100644
--- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs
+++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
@@ -1912,11 +1912,7 @@ fn check_mod_type_wf(tcx: TyCtxt<'_>, module: LocalModDefId) -> Result<(), Error
     res.and(items.par_foreign_items(|item| tcx.ensure().check_well_formed(item.owner_id)))
 }
 
-fn error_392(
-    tcx: TyCtxt<'_>,
-    span: Span,
-    param_name: Symbol,
-) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+fn error_392(tcx: TyCtxt<'_>, span: Span, param_name: Symbol) -> DiagnosticBuilder<'_> {
     let mut err = struct_span_err!(tcx.sess, span, E0392, "parameter `{param_name}` is never used");
     err.span_label(span, "unused parameter");
     err
diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs
index d48535c82f5..d43b4adfe39 100644
--- a/compiler/rustc_hir_analysis/src/collect.rs
+++ b/compiler/rustc_hir_analysis/src/collect.rs
@@ -181,7 +181,7 @@ pub(crate) fn placeholder_type_error_diag<'tcx>(
     suggest: bool,
     hir_ty: Option<&hir::Ty<'_>>,
     kind: &'static str,
-) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+) -> DiagnosticBuilder<'tcx> {
     if placeholder_types.is_empty() {
         return bad_placeholder(tcx, additional_spans, kind);
     }
@@ -333,7 +333,7 @@ fn bad_placeholder<'tcx>(
     tcx: TyCtxt<'tcx>,
     mut spans: Vec<Span>,
     kind: &'static str,
-) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+) -> DiagnosticBuilder<'tcx> {
     let kind = if kind.ends_with('s') { format!("{kind}es") } else { format!("{kind}s") };
 
     spans.sort();
diff --git a/compiler/rustc_hir_analysis/src/structured_errors.rs b/compiler/rustc_hir_analysis/src/structured_errors.rs
index 0b46fce1735..04d04304e70 100644
--- a/compiler/rustc_hir_analysis/src/structured_errors.rs
+++ b/compiler/rustc_hir_analysis/src/structured_errors.rs
@@ -6,7 +6,7 @@ pub use self::{
     missing_cast_for_variadic_arg::*, sized_unsized_cast::*, wrong_number_of_generic_args::*,
 };
 
-use rustc_errors::{DiagnosticBuilder, DiagnosticId, ErrorGuaranteed};
+use rustc_errors::{DiagnosticBuilder, DiagnosticId};
 use rustc_session::Session;
 
 pub trait StructuredDiagnostic<'tcx> {
@@ -14,7 +14,7 @@ pub trait StructuredDiagnostic<'tcx> {
 
     fn code(&self) -> DiagnosticId;
 
-    fn diagnostic(&self) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn diagnostic(&self) -> DiagnosticBuilder<'tcx> {
         let err = self.diagnostic_common();
 
         if self.session().teach(&self.code()) {
@@ -24,19 +24,13 @@ pub trait StructuredDiagnostic<'tcx> {
         }
     }
 
-    fn diagnostic_common(&self) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>;
+    fn diagnostic_common(&self) -> DiagnosticBuilder<'tcx>;
 
-    fn diagnostic_regular(
-        &self,
-        err: DiagnosticBuilder<'tcx, ErrorGuaranteed>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn diagnostic_regular(&self, err: DiagnosticBuilder<'tcx>) -> DiagnosticBuilder<'tcx> {
         err
     }
 
-    fn diagnostic_extended(
-        &self,
-        err: DiagnosticBuilder<'tcx, ErrorGuaranteed>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn diagnostic_extended(&self, err: DiagnosticBuilder<'tcx>) -> DiagnosticBuilder<'tcx> {
         err
     }
 }
diff --git a/compiler/rustc_hir_analysis/src/structured_errors/missing_cast_for_variadic_arg.rs b/compiler/rustc_hir_analysis/src/structured_errors/missing_cast_for_variadic_arg.rs
index c37dff61b72..7cc4982820b 100644
--- a/compiler/rustc_hir_analysis/src/structured_errors/missing_cast_for_variadic_arg.rs
+++ b/compiler/rustc_hir_analysis/src/structured_errors/missing_cast_for_variadic_arg.rs
@@ -1,5 +1,5 @@
 use crate::{errors, structured_errors::StructuredDiagnostic};
-use rustc_errors::{DiagnosticBuilder, DiagnosticId, ErrorGuaranteed};
+use rustc_errors::{DiagnosticBuilder, DiagnosticId};
 use rustc_middle::ty::{Ty, TypeVisitableExt};
 use rustc_session::Session;
 use rustc_span::Span;
@@ -20,7 +20,7 @@ impl<'tcx> StructuredDiagnostic<'tcx> for MissingCastForVariadicArg<'tcx, '_> {
         rustc_errors::error_code!(E0617)
     }
 
-    fn diagnostic_common(&self) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn diagnostic_common(&self) -> DiagnosticBuilder<'tcx> {
         let (sugg_span, replace, help) =
             if let Ok(snippet) = self.sess.source_map().span_to_snippet(self.span) {
                 (Some(self.span), format!("{} as {}", snippet, self.cast_ty), None)
@@ -44,10 +44,7 @@ impl<'tcx> StructuredDiagnostic<'tcx> for MissingCastForVariadicArg<'tcx, '_> {
         err
     }
 
-    fn diagnostic_extended(
-        &self,
-        mut err: DiagnosticBuilder<'tcx, ErrorGuaranteed>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn diagnostic_extended(&self, mut err: DiagnosticBuilder<'tcx>) -> DiagnosticBuilder<'tcx> {
         err.note(format!(
             "certain types, like `{}`, must be casted before passing them to a \
                 variadic function, because of arcane ABI rules dictated by the C \
diff --git a/compiler/rustc_hir_analysis/src/structured_errors/sized_unsized_cast.rs b/compiler/rustc_hir_analysis/src/structured_errors/sized_unsized_cast.rs
index 910417abe6e..6ba27f49744 100644
--- a/compiler/rustc_hir_analysis/src/structured_errors/sized_unsized_cast.rs
+++ b/compiler/rustc_hir_analysis/src/structured_errors/sized_unsized_cast.rs
@@ -1,5 +1,5 @@
 use crate::{errors, structured_errors::StructuredDiagnostic};
-use rustc_errors::{DiagnosticBuilder, DiagnosticId, ErrorGuaranteed};
+use rustc_errors::{DiagnosticBuilder, DiagnosticId};
 use rustc_middle::ty::{Ty, TypeVisitableExt};
 use rustc_session::Session;
 use rustc_span::Span;
@@ -20,7 +20,7 @@ impl<'tcx> StructuredDiagnostic<'tcx> for SizedUnsizedCast<'tcx> {
         rustc_errors::error_code!(E0607)
     }
 
-    fn diagnostic_common(&self) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn diagnostic_common(&self) -> DiagnosticBuilder<'tcx> {
         let mut err = self.sess.create_err(errors::CastThinPointerToFatPointer {
             span: self.span,
             expr_ty: self.expr_ty,
@@ -34,10 +34,7 @@ impl<'tcx> StructuredDiagnostic<'tcx> for SizedUnsizedCast<'tcx> {
         err
     }
 
-    fn diagnostic_extended(
-        &self,
-        mut err: DiagnosticBuilder<'tcx, ErrorGuaranteed>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn diagnostic_extended(&self, mut err: DiagnosticBuilder<'tcx>) -> DiagnosticBuilder<'tcx> {
         err.help(
             "Thin pointers are \"simple\" pointers: they are purely a reference to a
 memory address.
diff --git a/compiler/rustc_hir_analysis/src/structured_errors/wrong_number_of_generic_args.rs b/compiler/rustc_hir_analysis/src/structured_errors/wrong_number_of_generic_args.rs
index fab841e3679..c7818d80dbf 100644
--- a/compiler/rustc_hir_analysis/src/structured_errors/wrong_number_of_generic_args.rs
+++ b/compiler/rustc_hir_analysis/src/structured_errors/wrong_number_of_generic_args.rs
@@ -1,7 +1,6 @@
 use crate::structured_errors::StructuredDiagnostic;
 use rustc_errors::{
-    pluralize, Applicability, Diagnostic, DiagnosticBuilder, DiagnosticId, ErrorGuaranteed,
-    MultiSpan,
+    pluralize, Applicability, Diagnostic, DiagnosticBuilder, DiagnosticId, MultiSpan,
 };
 use rustc_hir as hir;
 use rustc_middle::ty::{self as ty, AssocItems, AssocKind, TyCtxt};
@@ -521,7 +520,7 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
         }
     }
 
-    fn start_diagnostics(&self) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn start_diagnostics(&self) -> DiagnosticBuilder<'tcx> {
         let span = self.path_segment.ident.span;
         let msg = self.create_error_message();
 
@@ -1113,7 +1112,7 @@ impl<'tcx> StructuredDiagnostic<'tcx> for WrongNumberOfGenericArgs<'_, 'tcx> {
         rustc_errors::error_code!(E0107)
     }
 
-    fn diagnostic_common(&self) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    fn diagnostic_common(&self) -> DiagnosticBuilder<'tcx> {
         let mut err = self.start_diagnostics();
 
         self.notify(&mut err);
diff --git a/compiler/rustc_hir_typeck/src/cast.rs b/compiler/rustc_hir_typeck/src/cast.rs
index 0de0365364c..9783fe79a90 100644
--- a/compiler/rustc_hir_typeck/src/cast.rs
+++ b/compiler/rustc_hir_typeck/src/cast.rs
@@ -187,7 +187,7 @@ fn make_invalid_casting_error<'a, 'tcx>(
     expr_ty: Ty<'tcx>,
     cast_ty: Ty<'tcx>,
     fcx: &FnCtxt<'a, 'tcx>,
-) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+) -> DiagnosticBuilder<'a> {
     type_error_struct!(
         sess,
         span,
diff --git a/compiler/rustc_hir_typeck/src/coercion.rs b/compiler/rustc_hir_typeck/src/coercion.rs
index 61236c07135..aed2dbb4505 100644
--- a/compiler/rustc_hir_typeck/src/coercion.rs
+++ b/compiler/rustc_hir_typeck/src/coercion.rs
@@ -36,9 +36,7 @@
 //! ```
 
 use crate::FnCtxt;
-use rustc_errors::{
-    struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, MultiSpan,
-};
+use rustc_errors::{struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::{self, Visitor};
@@ -1772,7 +1770,7 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
         id: hir::HirId,
         expression: Option<&'tcx hir::Expr<'tcx>>,
         blk_id: Option<hir::HirId>,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'a> {
         let mut err = fcx.err_ctxt().report_mismatched_types(cause, expected, found, ty_err);
 
         let parent_id = fcx.tcx.hir().parent_id(id);
diff --git a/compiler/rustc_hir_typeck/src/demand.rs b/compiler/rustc_hir_typeck/src/demand.rs
index 8b666c63425..6e5bd740b2e 100644
--- a/compiler/rustc_hir_typeck/src/demand.rs
+++ b/compiler/rustc_hir_typeck/src/demand.rs
@@ -1,6 +1,6 @@
 use crate::FnCtxt;
 use rustc_errors::MultiSpan;
-use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed};
+use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder};
 use rustc_hir as hir;
 use rustc_hir::def::Res;
 use rustc_hir::intravisit::Visitor;
@@ -168,7 +168,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         sp: Span,
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'tcx>> {
         self.demand_suptype_with_origin(&self.misc(sp), expected, actual)
     }
 
@@ -178,7 +178,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         cause: &ObligationCause<'tcx>,
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'tcx>> {
         match self.at(cause, self.param_env).sup(DefineOpaqueTypes::Yes, expected, actual) {
             Ok(InferOk { obligations, value: () }) => {
                 self.register_predicates(obligations);
@@ -199,7 +199,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         sp: Span,
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'tcx>> {
         self.demand_eqtype_with_origin(&self.misc(sp), expected, actual)
     }
 
@@ -208,7 +208,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         cause: &ObligationCause<'tcx>,
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'tcx>> {
         match self.at(cause, self.param_env).eq(DefineOpaqueTypes::Yes, expected, actual) {
             Ok(InferOk { obligations, value: () }) => {
                 self.register_predicates(obligations);
@@ -246,7 +246,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expected: Ty<'tcx>,
         mut expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>,
         allow_two_phase: AllowTwoPhase,
-    ) -> (Ty<'tcx>, Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>>) {
+    ) -> (Ty<'tcx>, Option<DiagnosticBuilder<'tcx>>) {
         let expected = self.resolve_vars_with_obligations(expected);
 
         let e = match self.coerce(expr, checked_ty, expected, allow_two_phase, None) {
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
index 5d5b5f39ccf..c4755b852bd 100644
--- a/compiler/rustc_hir_typeck/src/expr.rs
+++ b/compiler/rustc_hir_typeck/src/expr.rs
@@ -966,7 +966,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     pub fn check_for_missing_semi(
         &self,
         expr: &'tcx hir::Expr<'tcx>,
-        err: &mut DiagnosticBuilder<'_, ErrorGuaranteed>,
+        err: &mut DiagnosticBuilder<'_>,
     ) -> bool {
         if let hir::ExprKind::Binary(binop, lhs, rhs) = expr.kind
             && let hir::BinOpKind::Mul = binop.node
@@ -2738,7 +2738,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         field: Ident,
         expr_t: Ty<'tcx>,
         id: HirId,
-    ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'_> {
         let span = field.span;
         debug!("no_such_field_err(span: {:?}, field: {:?}, expr_t: {:?})", span, field, expr_t);
 
@@ -2821,11 +2821,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         err
     }
 
-    fn private_field_err(
-        &self,
-        field: Ident,
-        base_did: DefId,
-    ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+    fn private_field_err(&self, field: Ident, base_did: DefId) -> DiagnosticBuilder<'_> {
         let struct_path = self.tcx().def_path_str(base_did);
         let kind_name = self.tcx().def_descr(base_did);
         let mut err = struct_span_err!(
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
index 4caa0df58b6..752401845cd 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
@@ -1258,7 +1258,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expected_ty: Ty<'tcx>,
         provided_ty: Ty<'tcx>,
         arg: &hir::Expr<'tcx>,
-        err: &mut rustc_errors::DiagnosticBuilder<'tcx, ErrorGuaranteed>,
+        err: &mut rustc_errors::DiagnosticBuilder<'tcx>,
     ) {
         if let ty::RawPtr(ty::TypeAndMut { mutbl: hir::Mutability::Mut, .. }) = expected_ty.kind()
             && let ty::RawPtr(ty::TypeAndMut { mutbl: hir::Mutability::Not, .. }) =
diff --git a/compiler/rustc_hir_typeck/src/method/suggest.rs b/compiler/rustc_hir_typeck/src/method/suggest.rs
index 7595f21d9f1..9327161eccb 100644
--- a/compiler/rustc_hir_typeck/src/method/suggest.rs
+++ b/compiler/rustc_hir_typeck/src/method/suggest.rs
@@ -13,8 +13,7 @@ use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_data_structures::unord::UnordSet;
 use rustc_errors::StashKey;
 use rustc_errors::{
-    pluralize, struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed,
-    MultiSpan,
+    pluralize, struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, MultiSpan,
 };
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
@@ -120,7 +119,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         args: Option<&'tcx [hir::Expr<'tcx>]>,
         expected: Expectation<'tcx>,
         trait_missing_method: bool,
-    ) -> Option<DiagnosticBuilder<'_, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'_>> {
         // Avoid suggestions when we don't know what's going on.
         if rcvr_ty.references_error() {
             return None;
@@ -261,7 +260,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         &self,
         rcvr_ty: Ty<'tcx>,
         rcvr_expr: &hir::Expr<'tcx>,
-    ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'_> {
         let mut file = None;
         let ty_str = self.tcx.short_ty_string(rcvr_ty, &mut file);
         let mut err = struct_span_err!(
@@ -299,7 +298,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         no_match_data: &mut NoMatchData<'tcx>,
         expected: Expectation<'tcx>,
         trait_missing_method: bool,
-    ) -> Option<DiagnosticBuilder<'_, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'_>> {
         let mode = no_match_data.mode;
         let tcx = self.tcx;
         let rcvr_ty = self.resolve_vars_if_possible(rcvr_ty);
diff --git a/compiler/rustc_hir_typeck/src/pat.rs b/compiler/rustc_hir_typeck/src/pat.rs
index 56a420fab4f..0c0af51cb0d 100644
--- a/compiler/rustc_hir_typeck/src/pat.rs
+++ b/compiler/rustc_hir_typeck/src/pat.rs
@@ -99,7 +99,7 @@ impl<'tcx> FnCtxt<'_, 'tcx> {
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
         ti: TopInfo<'tcx>,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'tcx>> {
         let mut diag =
             self.demand_eqtype_with_origin(&self.pattern_cause(ti, cause_span), expected, actual)?;
         if let Some(expr) = ti.origin_expr {
@@ -967,7 +967,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
     fn emit_bad_pat_path(
         &self,
-        mut e: DiagnosticBuilder<'_, ErrorGuaranteed>,
+        mut e: DiagnosticBuilder<'_>,
         pat: &hir::Pat<'tcx>,
         res: Res,
         pat_res: Res,
@@ -1508,7 +1508,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         variant: &VariantDef,
         pat: &'_ Pat<'_>,
         fields: &[hir::PatField<'_>],
-    ) -> Option<DiagnosticBuilder<'_, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'_>> {
         // if this is a tuple struct, then all field names will be numbers
         // so if any fields in a struct pattern use shorthand syntax, they will
         // be invalid identifiers (for example, Foo { 0, 1 }).
@@ -1584,7 +1584,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         pat: &'tcx Pat<'tcx>,
         variant: &ty::VariantDef,
         args: &'tcx ty::List<ty::GenericArg<'tcx>>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let tcx = self.tcx;
         let (field_names, t, plural) = if let [field] = inexistent_fields {
             (format!("a field named `{}`", field.ident), "this", "")
@@ -1689,7 +1689,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         pat: &Pat<'_>,
         fields: &'tcx [hir::PatField<'tcx>],
         variant: &ty::VariantDef,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'tcx>> {
         if let (Some(CtorKind::Fn), PatKind::Struct(qpath, pattern_fields, ..)) =
             (variant.ctor_kind(), &pat.kind)
         {
@@ -1775,7 +1775,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         &self,
         pat: &Pat<'_>,
         fields: &'tcx [hir::PatField<'tcx>],
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let mut err = self
             .tcx
             .sess
@@ -1867,7 +1867,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         unmentioned_fields: &[(&ty::FieldDef, Ident)],
         have_inaccessible_fields: bool,
         fields: &'tcx [hir::PatField<'tcx>],
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let inaccessible = if have_inaccessible_fields { " and inaccessible fields" } else { "" };
         let field_names = if let [(_, field)] = unmentioned_fields {
             format!("field `{field}`{inaccessible}")
diff --git a/compiler/rustc_infer/src/infer/error_reporting/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
index d396c41007b..d77c224f3c8 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/mod.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
@@ -306,7 +306,7 @@ pub fn unexpected_hidden_region_diagnostic<'tcx>(
     hidden_ty: Ty<'tcx>,
     hidden_region: ty::Region<'tcx>,
     opaque_ty_key: ty::OpaqueTypeKey<'tcx>,
-) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+) -> DiagnosticBuilder<'tcx> {
     let mut err = tcx.sess.create_err(errors::OpaqueCapturesLifetime {
         span,
         opaque_ty: Ty::new_opaque(tcx, opaque_ty_key.def_id.to_def_id(), opaque_ty_key.args),
@@ -2171,7 +2171,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         &self,
         trace: TypeTrace<'tcx>,
         terr: TypeError<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         debug!("report_and_explain_type_error(trace={:?}, terr={:?})", trace, terr);
 
         let span = trace.cause.span();
@@ -2319,7 +2319,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         origin: Option<SubregionOrigin<'tcx>>,
         bound_kind: GenericKind<'tcx>,
         sub: Region<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         if let Some(SubregionOrigin::CompareImplItemObligation {
             span,
             impl_item_def_id,
@@ -2732,7 +2732,7 @@ impl<'tcx> InferCtxt<'tcx> {
     fn report_inference_failure(
         &self,
         var_origin: RegionVariableOrigin,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let br_string = |br: ty::BoundRegionKind| {
             let mut s = match br {
                 ty::BrNamed(_, name) => name.to_string(),
diff --git a/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs b/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
index 700fb5d3510..fd38e52cfde 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
@@ -5,7 +5,7 @@ use crate::errors::{
 use crate::infer::error_reporting::TypeErrCtxt;
 use crate::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use crate::infer::InferCtxt;
-use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed, IntoDiagnosticArg};
+use rustc_errors::{DiagnosticBuilder, IntoDiagnosticArg};
 use rustc_hir as hir;
 use rustc_hir::def::Res;
 use rustc_hir::def::{CtorOf, DefKind, Namespace};
@@ -358,7 +358,7 @@ impl<'tcx> InferCtxt<'tcx> {
         span: Span,
         arg_data: InferenceDiagnosticsData,
         error_code: TypeAnnotationNeeded,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let source_kind = "other";
         let source_name = "";
         let failure_span = None;
@@ -406,7 +406,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         arg: GenericArg<'tcx>,
         error_code: TypeAnnotationNeeded,
         should_label_span: bool,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let arg = self.resolve_vars_if_possible(arg);
         let arg_data = self.extract_inference_diagnostics_data(arg, None);
 
diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mod.rs
index 2a70c4673b0..e13d1d38a89 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mod.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mod.rs
@@ -50,7 +50,7 @@ impl<'cx, 'tcx> NiceRegionError<'cx, 'tcx> {
         self.cx.tcx
     }
 
-    pub fn try_report_from_nll(&self) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    pub fn try_report_from_nll(&self) -> Option<DiagnosticBuilder<'tcx>> {
         // Due to the improved diagnostics returned by the MIR borrow checker, only a subset of
         // the nice region errors are required when running under the MIR borrow checker.
         self.try_report_named_anon_conflict()
diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/named_anon_conflict.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/named_anon_conflict.rs
index 1b43022f8f7..a5a69b77a05 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/named_anon_conflict.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/named_anon_conflict.rs
@@ -5,16 +5,14 @@ use crate::{
     errors::ExplicitLifetimeRequired,
     infer::error_reporting::nice_region_error::find_anon_type::find_anon_type,
 };
-use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed};
+use rustc_errors::DiagnosticBuilder;
 use rustc_middle::ty;
 use rustc_span::symbol::kw;
 
 impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
     /// When given a `ConcreteFailure` for a function with parameters containing a named region and
     /// an anonymous region, emit an descriptive diagnostic error.
-    pub(super) fn try_report_named_anon_conflict(
-        &self,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    pub(super) fn try_report_named_anon_conflict(&self) -> Option<DiagnosticBuilder<'tcx>> {
         let (span, sub, sup) = self.regions()?;
 
         debug!(
diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/placeholder_error.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/placeholder_error.rs
index d98ca995d71..45affb538a3 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/placeholder_error.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/placeholder_error.rs
@@ -8,7 +8,7 @@ use crate::infer::ValuePairs;
 use crate::infer::{SubregionOrigin, TypeTrace};
 use crate::traits::{ObligationCause, ObligationCauseCode};
 use rustc_data_structures::intern::Interned;
-use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed, IntoDiagnosticArg};
+use rustc_errors::{DiagnosticBuilder, IntoDiagnosticArg};
 use rustc_hir::def::Namespace;
 use rustc_hir::def_id::DefId;
 use rustc_middle::ty::error::ExpectedFound;
@@ -57,9 +57,7 @@ where
 impl<'tcx> NiceRegionError<'_, 'tcx> {
     /// When given a `ConcreteFailure` for a function with arguments containing a named region and
     /// an anonymous region, emit a descriptive diagnostic error.
-    pub(super) fn try_report_placeholder_conflict(
-        &self,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    pub(super) fn try_report_placeholder_conflict(&self) -> Option<DiagnosticBuilder<'tcx>> {
         match &self.error {
             ///////////////////////////////////////////////////////////////////////////
             // NB. The ordering of cases in this match is very
@@ -195,7 +193,7 @@ impl<'tcx> NiceRegionError<'_, 'tcx> {
         sub_placeholder: Option<Region<'tcx>>,
         sup_placeholder: Option<Region<'tcx>>,
         value_pairs: &ValuePairs<'tcx>,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'tcx>> {
         let (expected_args, found_args, trait_def_id) = match value_pairs {
             ValuePairs::PolyTraitRefs(ExpectedFound { expected, found })
                 if expected.def_id() == found.def_id() =>
@@ -238,7 +236,7 @@ impl<'tcx> NiceRegionError<'_, 'tcx> {
         trait_def_id: DefId,
         expected_args: GenericArgsRef<'tcx>,
         actual_args: GenericArgsRef<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let span = cause.span();
 
         let (leading_ellipsis, satisfy_span, where_span, dup_span, def_id) =
diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/placeholder_relation.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/placeholder_relation.rs
index f5b8912532b..51b65a9dd2d 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/placeholder_relation.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/placeholder_relation.rs
@@ -5,14 +5,12 @@ use crate::{
     },
 };
 use rustc_data_structures::intern::Interned;
-use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed};
+use rustc_errors::DiagnosticBuilder;
 use rustc_middle::ty::{self, RePlaceholder, Region};
 
 impl<'tcx> NiceRegionError<'_, 'tcx> {
     /// Emitted wwhen given a `ConcreteFailure` when relating two placeholders.
-    pub(super) fn try_report_placeholder_relation(
-        &self,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    pub(super) fn try_report_placeholder_relation(&self) -> Option<DiagnosticBuilder<'tcx>> {
         match &self.error {
             Some(RegionResolutionError::ConcreteFailure(
                 SubregionOrigin::RelateRegionParamBound(span),
diff --git a/compiler/rustc_infer/src/infer/error_reporting/note.rs b/compiler/rustc_infer/src/infer/error_reporting/note.rs
index 1f1c2bc20e2..73139d8e720 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/note.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/note.rs
@@ -5,7 +5,7 @@ use crate::errors::{
 use crate::fluent_generated as fluent;
 use crate::infer::error_reporting::{note_and_explain_region, TypeErrCtxt};
 use crate::infer::{self, SubregionOrigin};
-use rustc_errors::{AddToDiagnostic, Diagnostic, DiagnosticBuilder, ErrorGuaranteed};
+use rustc_errors::{AddToDiagnostic, Diagnostic, DiagnosticBuilder};
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_middle::traits::ObligationCauseCode;
 use rustc_middle::ty::error::TypeError;
@@ -78,7 +78,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         origin: SubregionOrigin<'tcx>,
         sub: Region<'tcx>,
         sup: Region<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let mut err = match origin {
             infer::Subtype(box trace) => {
                 let terr = TypeError::RegionsDoesNotOutlive(sup, sub);
@@ -350,7 +350,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         placeholder_origin: SubregionOrigin<'tcx>,
         sub: Region<'tcx>,
         sup: Region<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         // I can't think how to do better than this right now. -nikomatsakis
         debug!(?placeholder_origin, ?sub, ?sup, "report_placeholder_failure");
         match placeholder_origin {
diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
index e092bbbfdd6..a36735b7600 100644
--- a/compiler/rustc_infer/src/infer/mod.rs
+++ b/compiler/rustc_infer/src/infer/mod.rs
@@ -1740,9 +1740,9 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         sp: Span,
         mk_diag: M,
         actual_ty: Ty<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>
+    ) -> DiagnosticBuilder<'tcx>
     where
-        M: FnOnce(String) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>,
+        M: FnOnce(String) -> DiagnosticBuilder<'tcx>,
     {
         let actual_ty = self.resolve_vars_if_possible(actual_ty);
         debug!("type_error_struct_with_diag({:?}, {:?})", sp, actual_ty);
@@ -1763,7 +1763,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
         err: TypeError<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         self.report_and_explain_type_error(TypeTrace::types(cause, true, expected, actual), err)
     }
 
@@ -1773,7 +1773,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         expected: ty::Const<'tcx>,
         actual: ty::Const<'tcx>,
         err: TypeError<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         self.report_and_explain_type_error(TypeTrace::consts(cause, true, expected, actual), err)
     }
 }
diff --git a/compiler/rustc_infer/src/traits/error_reporting/mod.rs b/compiler/rustc_infer/src/traits/error_reporting/mod.rs
index b3cfd843ace..99fb4b33f24 100644
--- a/compiler/rustc_infer/src/traits/error_reporting/mod.rs
+++ b/compiler/rustc_infer/src/traits/error_reporting/mod.rs
@@ -2,7 +2,7 @@ use super::ObjectSafetyViolation;
 
 use crate::infer::InferCtxt;
 use rustc_data_structures::fx::FxIndexSet;
-use rustc_errors::{struct_span_err, DiagnosticBuilder, ErrorGuaranteed, MultiSpan};
+use rustc_errors::{struct_span_err, DiagnosticBuilder, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_middle::ty::print::with_no_trimmed_paths;
@@ -18,7 +18,7 @@ impl<'tcx> InferCtxt<'tcx> {
         impl_item_def_id: LocalDefId,
         trait_item_def_id: DefId,
         requirement: &dyn fmt::Display,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let mut err = struct_span_err!(
             self.tcx.sess,
             error_span,
@@ -44,7 +44,7 @@ pub fn report_object_safety_error<'tcx>(
     span: Span,
     trait_def_id: DefId,
     violations: &[ObjectSafetyViolation],
-) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+) -> DiagnosticBuilder<'tcx> {
     let trait_str = tcx.def_path_str(trait_def_id);
     let trait_span = tcx.hir().get_if_local(trait_def_id).and_then(|node| match node {
         hir::Node::Item(item) => Some(item.ident.span),
diff --git a/compiler/rustc_middle/src/mir/interpret/error.rs b/compiler/rustc_middle/src/mir/interpret/error.rs
index 41386793987..2cd2fcca9d5 100644
--- a/compiler/rustc_middle/src/mir/interpret/error.rs
+++ b/compiler/rustc_middle/src/mir/interpret/error.rs
@@ -90,10 +90,7 @@ pub type EvalToConstValueResult<'tcx> = Result<ConstValue<'tcx>, ErrorHandled>;
 /// This is needed in `thir::pattern::lower_inline_const`.
 pub type EvalToValTreeResult<'tcx> = Result<Option<ValTree<'tcx>>, ErrorHandled>;
 
-pub fn struct_error<'tcx>(
-    tcx: TyCtxtAt<'tcx>,
-    msg: &str,
-) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+pub fn struct_error<'tcx>(tcx: TyCtxtAt<'tcx>, msg: &str) -> DiagnosticBuilder<'tcx> {
     struct_span_err!(tcx.sess, tcx.span, E0080, "{}", msg)
 }
 
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 35c135830c3..36b8d387d69 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -1481,7 +1481,7 @@ impl<'tcx> OpaqueHiddenType<'tcx> {
         other: &Self,
         opaque_def_id: LocalDefId,
         tcx: TyCtxt<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         if let Some(diag) = tcx
             .sess
             .dcx()
diff --git a/compiler/rustc_mir_build/src/errors.rs b/compiler/rustc_mir_build/src/errors.rs
index 22d0a665489..8677cba6a7c 100644
--- a/compiler/rustc_mir_build/src/errors.rs
+++ b/compiler/rustc_mir_build/src/errors.rs
@@ -2,7 +2,7 @@ use crate::fluent_generated as fluent;
 use rustc_errors::DiagnosticArgValue;
 use rustc_errors::{
     error_code, AddToDiagnostic, Applicability, DiagCtxt, Diagnostic, DiagnosticBuilder,
-    ErrorGuaranteed, IntoDiagnostic, Level, MultiSpan, SubdiagnosticMessage,
+    IntoDiagnostic, Level, MultiSpan, SubdiagnosticMessage,
 };
 use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
 use rustc_middle::ty::{self, Ty};
@@ -461,11 +461,7 @@ pub(crate) struct NonExhaustivePatternsTypeNotEmpty<'p, 'tcx, 'm> {
 }
 
 impl<'a> IntoDiagnostic<'a> for NonExhaustivePatternsTypeNotEmpty<'_, '_, '_> {
-    fn into_diagnostic(
-        self,
-        dcx: &'a DiagCtxt,
-        level: Level,
-    ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+    fn into_diagnostic(self, dcx: &'a DiagCtxt, level: Level) -> DiagnosticBuilder<'_> {
         let mut diag = DiagnosticBuilder::new(
             dcx,
             level,
diff --git a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
index d67dc59c618..616cc870cf9 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
@@ -54,11 +54,7 @@ pub(crate) fn check_match(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(), Err
     visitor.error
 }
 
-fn create_e0004(
-    sess: &Session,
-    sp: Span,
-    error_message: String,
-) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+fn create_e0004(sess: &Session, sp: Span, error_message: String) -> DiagnosticBuilder<'_> {
     struct_span_err!(sess, sp, E0004, "{}", &error_message)
 }
 
diff --git a/compiler/rustc_parse/src/errors.rs b/compiler/rustc_parse/src/errors.rs
index 8ccfcb625a6..53cce9e2883 100644
--- a/compiler/rustc_parse/src/errors.rs
+++ b/compiler/rustc_parse/src/errors.rs
@@ -3,8 +3,8 @@ use std::borrow::Cow;
 use rustc_ast::token::Token;
 use rustc_ast::{Path, Visibility};
 use rustc_errors::{
-    AddToDiagnostic, Applicability, DiagCtxt, DiagnosticBuilder, ErrorGuaranteed, IntoDiagnostic,
-    Level, SubdiagnosticMessage,
+    AddToDiagnostic, Applicability, DiagCtxt, DiagnosticBuilder, IntoDiagnostic, Level,
+    SubdiagnosticMessage,
 };
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_session::errors::ExprParenthesesNeeded;
@@ -1043,11 +1043,7 @@ pub(crate) struct ExpectedIdentifier {
 
 impl<'a> IntoDiagnostic<'a> for ExpectedIdentifier {
     #[track_caller]
-    fn into_diagnostic(
-        self,
-        dcx: &'a DiagCtxt,
-        level: Level,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    fn into_diagnostic(self, dcx: &'a DiagCtxt, level: Level) -> DiagnosticBuilder<'a> {
         let token_descr = TokenDescription::from_token(&self.token);
 
         let mut diag = DiagnosticBuilder::new(
@@ -1107,11 +1103,7 @@ pub(crate) struct ExpectedSemi {
 
 impl<'a> IntoDiagnostic<'a> for ExpectedSemi {
     #[track_caller]
-    fn into_diagnostic(
-        self,
-        dcx: &'a DiagCtxt,
-        level: Level,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    fn into_diagnostic(self, dcx: &'a DiagCtxt, level: Level) -> DiagnosticBuilder<'a> {
         let token_descr = TokenDescription::from_token(&self.token);
 
         let mut diag = DiagnosticBuilder::new(
diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index f19d420bb49..4d557e495d8 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -35,7 +35,7 @@ use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::{
     pluralize, AddToDiagnostic, Applicability, DiagCtxt, Diagnostic, DiagnosticBuilder,
-    DiagnosticMessage, ErrorGuaranteed, FatalError, MultiSpan, PResult,
+    DiagnosticMessage, FatalError, MultiSpan, PResult,
 };
 use rustc_session::errors::ExprParenthesesNeeded;
 use rustc_span::source_map::Spanned;
@@ -245,7 +245,7 @@ impl<'a> Parser<'a> {
         &self,
         sp: S,
         m: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'a> {
         self.dcx().struct_span_err(sp, m)
     }
 
@@ -413,7 +413,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    pub(super) fn expected_ident_found_err(&mut self) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    pub(super) fn expected_ident_found_err(&mut self) -> DiagnosticBuilder<'a> {
         self.expected_ident_found(false).unwrap_err()
     }
 
@@ -958,7 +958,7 @@ impl<'a> Parser<'a> {
 
     pub(super) fn recover_closure_body(
         &mut self,
-        mut err: DiagnosticBuilder<'a, ErrorGuaranteed>,
+        mut err: DiagnosticBuilder<'a>,
         before: token::Token,
         prev: token::Token,
         token: token::Token,
@@ -1189,7 +1189,7 @@ impl<'a> Parser<'a> {
     /// encounter a parse error when encountering the first `,`.
     pub(super) fn check_mistyped_turbofish_with_multiple_type_params(
         &mut self,
-        mut e: DiagnosticBuilder<'a, ErrorGuaranteed>,
+        mut e: DiagnosticBuilder<'a>,
         expr: &mut P<Expr>,
     ) -> PResult<'a, ()> {
         if let ExprKind::Binary(binop, _, _) = &expr.kind
@@ -1234,10 +1234,7 @@ impl<'a> Parser<'a> {
 
     /// Suggest add the missing `let` before the identifier in stmt
     /// `a: Ty = 1` -> `let a: Ty = 1`
-    pub(super) fn suggest_add_missing_let_for_stmt(
-        &mut self,
-        err: &mut DiagnosticBuilder<'a, ErrorGuaranteed>,
-    ) {
+    pub(super) fn suggest_add_missing_let_for_stmt(&mut self, err: &mut DiagnosticBuilder<'a>) {
         if self.token == token::Colon {
             let prev_span = self.prev_token.span.shrink_to_lo();
             let snapshot = self.create_snapshot_for_diagnostic();
@@ -2320,7 +2317,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    pub(super) fn expected_expression_found(&self) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    pub(super) fn expected_expression_found(&self) -> DiagnosticBuilder<'a> {
         let (span, msg) = match (&self.token.kind, self.subparser_name) {
             (&token::Eof, Some(origin)) => {
                 let sp = self.prev_token.span.shrink_to_hi();
@@ -2572,7 +2569,7 @@ impl<'a> Parser<'a> {
     pub fn recover_const_arg(
         &mut self,
         start: Span,
-        mut err: DiagnosticBuilder<'a, ErrorGuaranteed>,
+        mut err: DiagnosticBuilder<'a>,
     ) -> PResult<'a, GenericArg> {
         let is_op_or_dot = AssocOp::from_token(&self.token)
             .and_then(|op| {
@@ -2674,7 +2671,7 @@ impl<'a> Parser<'a> {
     /// Creates a dummy const argument, and reports that the expression must be enclosed in braces
     pub fn dummy_const_arg_needs_braces(
         &self,
-        mut err: DiagnosticBuilder<'a, ErrorGuaranteed>,
+        mut err: DiagnosticBuilder<'a>,
         span: Span,
     ) -> GenericArg {
         err.multipart_suggestion(
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index e653d4064c8..a6783eaf8d4 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -26,8 +26,7 @@ use rustc_ast::{ClosureBinder, MetaItemLit, StmtKind};
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_errors::{
-    AddToDiagnostic, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, PResult,
-    StashKey,
+    AddToDiagnostic, Applicability, Diagnostic, DiagnosticBuilder, PResult, StashKey,
 };
 use rustc_macros::Subdiagnostic;
 use rustc_session::errors::{report_lit_error, ExprParenthesesNeeded};
@@ -1691,7 +1690,7 @@ impl<'a> Parser<'a> {
         &self,
         lifetime: Ident,
         mk_lit_char: impl FnOnce(Symbol, Span) -> L,
-        err: impl FnOnce(&Self) -> DiagnosticBuilder<'a, ErrorGuaranteed>,
+        err: impl FnOnce(&Self) -> DiagnosticBuilder<'a>,
     ) -> L {
         if let Some(mut diag) = self.dcx().steal_diagnostic(lifetime.span, StashKey::LifetimeIsChar)
         {
diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs
index 0ab2adb404a..47c337ad913 100644
--- a/compiler/rustc_parse/src/parser/mod.rs
+++ b/compiler/rustc_parse/src/parser/mod.rs
@@ -32,7 +32,7 @@ use rustc_ast::{HasAttrs, HasTokens, Unsafe, Visibility, VisibilityKind};
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::PResult;
-use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed, FatalError, MultiSpan};
+use rustc_errors::{Applicability, DiagnosticBuilder, FatalError, MultiSpan};
 use rustc_session::parse::ParseSess;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
@@ -908,7 +908,7 @@ impl<'a> Parser<'a> {
     fn recover_missing_braces_around_closure_body(
         &mut self,
         closure_spans: ClosureSpans,
-        mut expect_err: DiagnosticBuilder<'_, ErrorGuaranteed>,
+        mut expect_err: DiagnosticBuilder<'_>,
     ) -> PResult<'a, ()> {
         let initial_semicolon = self.token.span;
 
@@ -1490,7 +1490,7 @@ impl<'a> Parser<'a> {
 pub(crate) fn make_unclosed_delims_error(
     unmatched: UnmatchedDelim,
     sess: &ParseSess,
-) -> Option<DiagnosticBuilder<'_, ErrorGuaranteed>> {
+) -> Option<DiagnosticBuilder<'_>> {
     // `None` here means an `Eof` was found. We already emit those errors elsewhere, we add them to
     // `unmatched_delims` only for error recovery in the `Parser`.
     let found_delim = unmatched.found_delim?;
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs
index d32582fd43d..56a3f5ce3c2 100644
--- a/compiler/rustc_parse/src/parser/pat.rs
+++ b/compiler/rustc_parse/src/parser/pat.rs
@@ -18,7 +18,7 @@ use rustc_ast::{
     PatField, PatKind, Path, QSelf, RangeEnd, RangeSyntax,
 };
 use rustc_ast_pretty::pprust;
-use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed, PResult};
+use rustc_errors::{Applicability, DiagnosticBuilder, PResult};
 use rustc_session::errors::ExprParenthesesNeeded;
 use rustc_span::source_map::{respan, Spanned};
 use rustc_span::symbol::{kw, sym, Ident};
@@ -687,7 +687,7 @@ impl<'a> Parser<'a> {
 
     fn fatal_unexpected_non_pat(
         &mut self,
-        err: DiagnosticBuilder<'a, ErrorGuaranteed>,
+        err: DiagnosticBuilder<'a>,
         expected: Option<Expected>,
     ) -> PResult<'a, P<Pat>> {
         err.cancel();
@@ -969,7 +969,7 @@ impl<'a> Parser<'a> {
         let mut fields = ThinVec::new();
         let mut etc = false;
         let mut ate_comma = true;
-        let mut delayed_err: Option<DiagnosticBuilder<'a, ErrorGuaranteed>> = None;
+        let mut delayed_err: Option<DiagnosticBuilder<'a>> = None;
         let mut first_etc_and_maybe_comma_span = None;
         let mut last_non_comma_dotdot_span = None;
 
@@ -1135,7 +1135,7 @@ impl<'a> Parser<'a> {
     fn recover_misplaced_pattern_modifiers(
         &self,
         fields: &ThinVec<PatField>,
-        err: &mut DiagnosticBuilder<'a, ErrorGuaranteed>,
+        err: &mut DiagnosticBuilder<'a>,
     ) {
         if let Some(last) = fields.iter().last()
             && last.is_shorthand
diff --git a/compiler/rustc_parse/src/parser/stmt.rs b/compiler/rustc_parse/src/parser/stmt.rs
index 1ee5a96d5dc..1ac5aba212c 100644
--- a/compiler/rustc_parse/src/parser/stmt.rs
+++ b/compiler/rustc_parse/src/parser/stmt.rs
@@ -19,7 +19,7 @@ use rustc_ast::util::classify;
 use rustc_ast::{AttrStyle, AttrVec, LocalKind, MacCall, MacCallStmt, MacStmtStyle};
 use rustc_ast::{Block, BlockCheckMode, Expr, ExprKind, HasAttrs, Local, Stmt};
 use rustc_ast::{StmtKind, DUMMY_NODE_ID};
-use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed, PResult};
+use rustc_errors::{Applicability, DiagnosticBuilder, PResult};
 use rustc_span::symbol::{kw, sym, Ident};
 use rustc_span::{BytePos, Span};
 
@@ -442,7 +442,7 @@ impl<'a> Parser<'a> {
     fn error_block_no_opening_brace_msg(
         &mut self,
         msg: Cow<'static, str>,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'a> {
         let sp = self.token.span;
         let mut e = self.struct_span_err(sp, msg);
         let do_not_suggest_help = self.token.is_keyword(kw::In) || self.token == token::Colon;
diff --git a/compiler/rustc_query_system/src/query/job.rs b/compiler/rustc_query_system/src/query/job.rs
index 0561fd147a9..982b9ee94da 100644
--- a/compiler/rustc_query_system/src/query/job.rs
+++ b/compiler/rustc_query_system/src/query/job.rs
@@ -4,7 +4,7 @@ use crate::query::plumbing::CycleError;
 use crate::query::DepKind;
 use crate::query::{QueryContext, QueryStackFrame};
 use rustc_data_structures::fx::FxHashMap;
-use rustc_errors::{DiagCtxt, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, Level};
+use rustc_errors::{DiagCtxt, Diagnostic, DiagnosticBuilder, Level};
 use rustc_hir::def::DefKind;
 use rustc_session::Session;
 use rustc_span::Span;
@@ -559,7 +559,7 @@ pub fn deadlock(query_map: QueryMap, registry: &rayon_core::Registry) {
 pub(crate) fn report_cycle<'a>(
     sess: &'a Session,
     CycleError { usage, cycle: stack }: &CycleError,
-) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+) -> DiagnosticBuilder<'a> {
     assert!(!stack.is_empty());
 
     let span = stack[0].query.default_span(stack[1 % stack.len()].span);
diff --git a/compiler/rustc_query_system/src/query/plumbing.rs b/compiler/rustc_query_system/src/query/plumbing.rs
index 41638b38c74..3e29574c871 100644
--- a/compiler/rustc_query_system/src/query/plumbing.rs
+++ b/compiler/rustc_query_system/src/query/plumbing.rs
@@ -19,7 +19,7 @@ use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_data_structures::sync::Lock;
 #[cfg(parallel_compiler)]
 use rustc_data_structures::{outline, sync};
-use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed, FatalError, StashKey};
+use rustc_errors::{DiagnosticBuilder, FatalError, StashKey};
 use rustc_span::{Span, DUMMY_SP};
 use std::cell::Cell;
 use std::collections::hash_map::Entry;
@@ -112,7 +112,7 @@ fn handle_cycle_error<Q, Qcx>(
     query: Q,
     qcx: Qcx,
     cycle_error: &CycleError,
-    mut error: DiagnosticBuilder<'_, ErrorGuaranteed>,
+    mut error: DiagnosticBuilder<'_>,
 ) -> Q::Value
 where
     Q: QueryConfig<Qcx>,
diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index 542aff69e34..af0c5b56d73 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -551,7 +551,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
         &mut self,
         span: Span,
         resolution_error: ResolutionError<'a>,
-    ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'_> {
         match resolution_error {
             ResolutionError::GenericParamsFromOuterItem(outer_res, has_generic_params) => {
                 use errs::GenericParamsFromOuterItemLabel as Label;
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index 5a02e7f3269..e410e76abf4 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -424,7 +424,7 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
         span: Span,
         source: PathSource<'_>,
         res: Option<Res>,
-    ) -> (DiagnosticBuilder<'tcx, ErrorGuaranteed>, Vec<ImportSuggestion>) {
+    ) -> (DiagnosticBuilder<'tcx>, Vec<ImportSuggestion>) {
         debug!(?res, ?source);
         let base_error = self.make_base_error(path, span, source, res);
 
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index 75ec594eb9b..a14f3d494fb 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -37,7 +37,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet};
 use rustc_data_structures::intern::Interned;
 use rustc_data_structures::steal::Steal;
 use rustc_data_structures::sync::{FreezeReadGuard, Lrc};
-use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed};
+use rustc_errors::{Applicability, DiagnosticBuilder};
 use rustc_expand::base::{DeriveResolutions, SyntaxExtension, SyntaxExtensionKind};
 use rustc_feature::BUILTIN_ATTRIBUTES;
 use rustc_hir::def::Namespace::{self, *};
@@ -704,7 +704,7 @@ struct PrivacyError<'a> {
 
 #[derive(Debug)]
 struct UseError<'a> {
-    err: DiagnosticBuilder<'a, ErrorGuaranteed>,
+    err: DiagnosticBuilder<'a>,
     /// Candidates which user could `use` to access the missing type.
     candidates: Vec<ImportSuggestion>,
     /// The `DefId` of the module to place the use-statements in.
diff --git a/compiler/rustc_session/src/errors.rs b/compiler/rustc_session/src/errors.rs
index 8ab31f6f382..9f7d918d98b 100644
--- a/compiler/rustc_session/src/errors.rs
+++ b/compiler/rustc_session/src/errors.rs
@@ -4,8 +4,7 @@ use crate::parse::ParseSess;
 use rustc_ast::token;
 use rustc_ast::util::literal::LitError;
 use rustc_errors::{
-    error_code, DiagCtxt, DiagnosticBuilder, DiagnosticMessage, ErrorGuaranteed, IntoDiagnostic,
-    Level, MultiSpan,
+    error_code, DiagCtxt, DiagnosticBuilder, DiagnosticMessage, IntoDiagnostic, Level, MultiSpan,
 };
 use rustc_macros::Diagnostic;
 use rustc_span::{BytePos, Span, Symbol};
@@ -18,11 +17,7 @@ pub struct FeatureGateError {
 
 impl<'a> IntoDiagnostic<'a> for FeatureGateError {
     #[track_caller]
-    fn into_diagnostic(
-        self,
-        dcx: &'a DiagCtxt,
-        level: Level,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    fn into_diagnostic(self, dcx: &'a DiagCtxt, level: Level) -> DiagnosticBuilder<'a> {
         let mut diag = DiagnosticBuilder::new(dcx, level, self.explain);
         diag.set_span(self.span);
         diag.code(error_code!(E0658));
diff --git a/compiler/rustc_session/src/parse.rs b/compiler/rustc_session/src/parse.rs
index b33cc83f9cf..52a637b74e7 100644
--- a/compiler/rustc_session/src/parse.rs
+++ b/compiler/rustc_session/src/parse.rs
@@ -83,7 +83,7 @@ pub fn feature_err(
     feature: Symbol,
     span: impl Into<MultiSpan>,
     explain: impl Into<DiagnosticMessage>,
-) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+) -> DiagnosticBuilder<'_> {
     feature_err_issue(sess, feature, span, GateIssue::Language, explain)
 }
 
@@ -98,7 +98,7 @@ pub fn feature_err_issue(
     span: impl Into<MultiSpan>,
     issue: GateIssue,
     explain: impl Into<DiagnosticMessage>,
-) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+) -> DiagnosticBuilder<'_> {
     let span = span.into();
 
     // Cancel an earlier warning for this same error, if it exists.
@@ -318,10 +318,7 @@ impl ParseSess {
     }
 
     #[track_caller]
-    pub fn create_err<'a>(
-        &'a self,
-        err: impl IntoDiagnostic<'a>,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    pub fn create_err<'a>(&'a self, err: impl IntoDiagnostic<'a>) -> DiagnosticBuilder<'a> {
         err.into_diagnostic(&self.dcx, Level::Error { lint: false })
     }
 
@@ -371,10 +368,7 @@ impl ParseSess {
 
     #[rustc_lint_diagnostics]
     #[track_caller]
-    pub fn struct_err(
-        &self,
-        msg: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+    pub fn struct_err(&self, msg: impl Into<DiagnosticMessage>) -> DiagnosticBuilder<'_> {
         self.dcx.struct_err(msg)
     }
 
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index 358219c630f..fc006e4e9d1 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -354,7 +354,7 @@ impl Session {
         &self,
         sp: S,
         msg: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'_> {
         self.dcx().struct_span_err(sp, msg)
     }
     #[rustc_lint_diagnostics]
@@ -364,16 +364,13 @@ impl Session {
         sp: S,
         msg: impl Into<DiagnosticMessage>,
         code: DiagnosticId,
-    ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'_> {
         self.dcx().struct_span_err_with_code(sp, msg, code)
     }
     // FIXME: This method should be removed (every error should have an associated error code).
     #[rustc_lint_diagnostics]
     #[track_caller]
-    pub fn struct_err(
-        &self,
-        msg: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+    pub fn struct_err(&self, msg: impl Into<DiagnosticMessage>) -> DiagnosticBuilder<'_> {
         self.parse_sess.struct_err(msg)
     }
     #[track_caller]
@@ -382,7 +379,7 @@ impl Session {
         &self,
         msg: impl Into<DiagnosticMessage>,
         code: DiagnosticId,
-    ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'_> {
         self.dcx().struct_err_with_code(msg, code)
     }
     #[rustc_lint_diagnostics]
@@ -463,10 +460,7 @@ impl Session {
         self.dcx().err(msg)
     }
     #[track_caller]
-    pub fn create_err<'a>(
-        &'a self,
-        err: impl IntoDiagnostic<'a>,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    pub fn create_err<'a>(&'a self, err: impl IntoDiagnostic<'a>) -> DiagnosticBuilder<'a> {
         self.parse_sess.create_err(err)
     }
     #[track_caller]
@@ -474,7 +468,7 @@ impl Session {
         &'a self,
         err: impl IntoDiagnostic<'a>,
         feature: Symbol,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'a> {
         let mut err = self.parse_sess.create_err(err);
         if err.code.is_none() {
             err.code = std::option::Option::Some(error_code!(E0658));
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/infer_ctxt_ext.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/infer_ctxt_ext.rs
index 0190d5ab4be..676b40850b1 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/infer_ctxt_ext.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/infer_ctxt_ext.rs
@@ -1,7 +1,7 @@
 use crate::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use crate::infer::InferCtxt;
 use crate::traits::{Obligation, ObligationCause, ObligationCtxt};
-use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed};
+use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticBuilder};
 use rustc_hir as hir;
 use rustc_hir::Node;
 use rustc_middle::ty::{self, Ty};
@@ -29,7 +29,7 @@ pub trait InferCtxtExt<'tcx> {
         found_args: Vec<ArgKind>,
         is_closure: bool,
         closure_pipe_span: Option<Span>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>;
+    ) -> DiagnosticBuilder<'tcx>;
 
     /// Checks if the type implements one of `Fn`, `FnMut`, or `FnOnce`
     /// in that order, and returns the generic type corresponding to the
@@ -118,7 +118,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
         found_args: Vec<ArgKind>,
         is_closure: bool,
         closure_arg_span: Option<Span>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let kind = if is_closure { "closure" } else { "function" };
 
         let args_str = |arguments: &[ArgKind], other: &[ArgKind]| {
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
index a1b896d2251..e26ea7ee07b 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -14,7 +14,7 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_errors::{
     error_code, pluralize, struct_span_err, Applicability, Diagnostic, DiagnosticBuilder,
-    ErrorGuaranteed, MultiSpan, Style, SuggestionStyle,
+    MultiSpan, Style, SuggestionStyle,
 };
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
@@ -207,7 +207,7 @@ pub trait TypeErrCtxtExt<'tcx> {
 
     fn point_at_returns_when_relevant(
         &self,
-        err: &mut DiagnosticBuilder<'tcx, ErrorGuaranteed>,
+        err: &mut DiagnosticBuilder<'tcx>,
         obligation: &PredicateObligation<'tcx>,
     );
 
@@ -220,7 +220,7 @@ pub trait TypeErrCtxtExt<'tcx> {
         cause: &ObligationCauseCode<'tcx>,
         found_node: Option<Node<'_>>,
         param_env: ty::ParamEnv<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>;
+    ) -> DiagnosticBuilder<'tcx>;
 
     fn note_conflicting_fn_args(
         &self,
@@ -234,7 +234,7 @@ pub trait TypeErrCtxtExt<'tcx> {
     fn note_conflicting_closure_bounds(
         &self,
         cause: &ObligationCauseCode<'tcx>,
-        err: &mut DiagnosticBuilder<'tcx, ErrorGuaranteed>,
+        err: &mut DiagnosticBuilder<'tcx>,
     );
 
     fn suggest_fully_qualified_path(
@@ -1920,7 +1920,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
     fn point_at_returns_when_relevant(
         &self,
-        err: &mut DiagnosticBuilder<'tcx, ErrorGuaranteed>,
+        err: &mut DiagnosticBuilder<'tcx>,
         obligation: &PredicateObligation<'tcx>,
     ) {
         match obligation.cause.code().peel_derives() {
@@ -1961,7 +1961,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         cause: &ObligationCauseCode<'tcx>,
         found_node: Option<Node<'_>>,
         param_env: ty::ParamEnv<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         pub(crate) fn build_fn_sig_ty<'tcx>(
             infcx: &InferCtxt<'tcx>,
             trait_ref: ty::PolyTraitRef<'tcx>,
@@ -2187,7 +2187,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
     fn note_conflicting_closure_bounds(
         &self,
         cause: &ObligationCauseCode<'tcx>,
-        err: &mut DiagnosticBuilder<'tcx, ErrorGuaranteed>,
+        err: &mut DiagnosticBuilder<'tcx>,
     ) {
         // First, look for an `ExprBindingObligation`, which means we can get
         // the unsubstituted predicate list of the called function. And check
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs
index 9ee091bbd1e..fa820ea20a5 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs
@@ -59,7 +59,7 @@ pub trait TypeErrCtxtExt<'tcx> {
         predicate: &T,
         span: Span,
         suggest_increasing_limit: bool,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>
+    ) -> DiagnosticBuilder<'tcx>
     where
         T: fmt::Display + TypeFoldable<TyCtxt<'tcx>> + Print<'tcx, FmtPrinter<'tcx, 'tcx>>;
 
@@ -118,7 +118,7 @@ pub trait TypeErrCtxtExt<'tcx> {
         &self,
         ty: Ty<'tcx>,
         obligation: &PredicateObligation<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>;
+    ) -> DiagnosticBuilder<'tcx>;
 }
 
 impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
@@ -263,7 +263,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         predicate: &T,
         span: Span,
         suggest_increasing_limit: bool,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>
+    ) -> DiagnosticBuilder<'tcx>
     where
         T: fmt::Display + TypeFoldable<TyCtxt<'tcx>> + Print<'tcx, FmtPrinter<'tcx, 'tcx>>,
     {
@@ -1226,7 +1226,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         &self,
         ty: Ty<'tcx>,
         obligation: &PredicateObligation<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let span = obligation.cause.span;
 
         let mut diag = match ty.kind() {
@@ -1491,7 +1491,7 @@ pub(super) trait InferCtxtPrivExt<'tcx> {
         closure_def_id: DefId,
         found_kind: ty::ClosureKind,
         kind: ty::ClosureKind,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>;
+    ) -> DiagnosticBuilder<'tcx>;
 
     fn report_type_parameter_mismatch_cyclic_type_error(
         &self,
@@ -1499,13 +1499,13 @@ pub(super) trait InferCtxtPrivExt<'tcx> {
         found_trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>,
         expected_trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>,
         terr: TypeError<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>;
+    ) -> DiagnosticBuilder<'tcx>;
 
     fn report_opaque_type_auto_trait_leakage(
         &self,
         obligation: &PredicateObligation<'tcx>,
         def_id: DefId,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>;
+    ) -> DiagnosticBuilder<'tcx>;
 
     fn report_type_parameter_mismatch_error(
         &self,
@@ -1513,13 +1513,13 @@ pub(super) trait InferCtxtPrivExt<'tcx> {
         span: Span,
         found_trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>,
         expected_trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>>;
+    ) -> Option<DiagnosticBuilder<'tcx>>;
 
     fn report_not_const_evaluatable_error(
         &self,
         obligation: &PredicateObligation<'tcx>,
         span: Span,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>>;
+    ) -> Option<DiagnosticBuilder<'tcx>>;
 }
 
 impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
@@ -3305,7 +3305,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         closure_def_id: DefId,
         found_kind: ty::ClosureKind,
         kind: ty::ClosureKind,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let closure_span = self.tcx.def_span(closure_def_id);
 
         let mut err = ClosureKindMismatch {
@@ -3347,7 +3347,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         found_trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>,
         expected_trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>,
         terr: TypeError<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let self_ty = found_trait_ref.self_ty().skip_binder();
         let (cause, terr) = if let ty::Closure(def_id, _) = self_ty.kind() {
             (
@@ -3367,7 +3367,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         &self,
         obligation: &PredicateObligation<'tcx>,
         def_id: DefId,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
+    ) -> DiagnosticBuilder<'tcx> {
         let name = match self.tcx.opaque_type_origin(def_id.expect_local()) {
             hir::OpaqueTyOrigin::FnReturn(_) | hir::OpaqueTyOrigin::AsyncFn(_) => {
                 "opaque type".to_string()
@@ -3409,7 +3409,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         span: Span,
         found_trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>,
         expected_trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'tcx>> {
         let found_trait_ref = self.resolve_vars_if_possible(found_trait_ref);
         let expected_trait_ref = self.resolve_vars_if_possible(expected_trait_ref);
 
@@ -3515,7 +3515,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         &self,
         obligation: &PredicateObligation<'tcx>,
         span: Span,
-    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+    ) -> Option<DiagnosticBuilder<'tcx>> {
         if !self.tcx.features().generic_const_exprs {
             let mut err = self
                 .tcx
-- 
cgit 1.4.1-3-g733a5