Adding upstream version 1.69.0+dfsg1.upstream/1.69.0+dfsg1

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

10 files changed, 355 insertions, 186 deletions

diff --git a/compiler/rustc_errors/src/diagnostic.rs b/compiler/rustc_errors/src/diagnostic.rs
index 51b2ff6a0..9ed8ab674 100644
--- a/compiler/rustc_errors/src/diagnostic.rs
+++ b/compiler/rustc_errors/src/diagnostic.rs
@@ -7,7 +7,6 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_error_messages::fluent_value_from_str_list_sep_by_and;
 use rustc_error_messages::FluentValue;
 use rustc_lint_defs::{Applicability, LintExpectationId};
-use rustc_span::edition::LATEST_STABLE_EDITION;
 use rustc_span::symbol::Symbol;
 use rustc_span::{Span, DUMMY_SP};
 use std::borrow::Cow;
@@ -555,18 +554,6 @@ impl Diagnostic {
         self
     }
 
-    /// Help the user upgrade to the latest edition.
-    /// This is factored out to make sure it does the right thing with `Cargo.toml`.
-    pub fn help_use_latest_edition(&mut self) -> &mut Self {
-        if std::env::var_os("CARGO").is_some() {
-            self.help(&format!("set `edition = \"{}\"` in `Cargo.toml`", LATEST_STABLE_EDITION));
-        } else {
-            self.help(&format!("pass `--edition {}` to `rustc`", LATEST_STABLE_EDITION));
-        }
-        self.note("for more on editions, read https://doc.rust-lang.org/edition-guide");
-        self
-    }
-
     /// Disallow attaching suggestions this diagnostic.
     /// Any suggestions attached e.g. with the `span_suggestion_*` methods
     /// (before and after the call to `disable_suggestions`) will be ignored.
@@ -629,19 +616,27 @@ impl Diagnostic {
         applicability: Applicability,
         style: SuggestionStyle,
     ) -> &mut Self {
-        assert!(!suggestion.is_empty());
-        debug_assert!(
-            !(suggestion.iter().any(|(sp, text)| sp.is_empty() && text.is_empty())),
-            "Span must not be empty and have no suggestion"
+        let mut parts = suggestion
+            .into_iter()
+            .map(|(span, snippet)| SubstitutionPart { snippet, span })
+            .collect::<Vec<_>>();
+
+        parts.sort_unstable_by_key(|part| part.span);
+
+        assert!(!parts.is_empty());
+        debug_assert_eq!(
+            parts.iter().find(|part| part.span.is_empty() && part.snippet.is_empty()),
+            None,
+            "Span must not be empty and have no suggestion",
+        );
+        debug_assert_eq!(
+            parts.array_windows().find(|[a, b]| a.span.overlaps(b.span)),
+            None,
+            "suggestion must not have overlapping parts",
         );
 
         self.push_suggestion(CodeSuggestion {
-            substitutions: vec![Substitution {
-                parts: suggestion
-                    .into_iter()
-                    .map(|(span, snippet)| SubstitutionPart { snippet, span })
-                    .collect(),
-            }],
+            substitutions: vec![Substitution { parts }],
             msg: self.subdiagnostic_message_to_diagnostic_message(msg),
             style,
             applicability,
@@ -802,25 +797,34 @@ impl Diagnostic {
         suggestions: impl IntoIterator<Item = Vec<(Span, String)>>,
         applicability: Applicability,
     ) -> &mut Self {
-        let suggestions: Vec<_> = suggestions.into_iter().collect();
-        debug_assert!(
-            !(suggestions
-                .iter()
-                .flatten()
-                .any(|(sp, suggestion)| sp.is_empty() && suggestion.is_empty())),
-            "Span must not be empty and have no suggestion"
-        );
+        let substitutions = suggestions
+            .into_iter()
+            .map(|sugg| {
+                let mut parts = sugg
+                    .into_iter()
+                    .map(|(span, snippet)| SubstitutionPart { snippet, span })
+                    .collect::<Vec<_>>();
+
+                parts.sort_unstable_by_key(|part| part.span);
+
+                assert!(!parts.is_empty());
+                debug_assert_eq!(
+                    parts.iter().find(|part| part.span.is_empty() && part.snippet.is_empty()),
+                    None,
+                    "Span must not be empty and have no suggestion",
+                );
+                debug_assert_eq!(
+                    parts.array_windows().find(|[a, b]| a.span.overlaps(b.span)),
+                    None,
+                    "suggestion must not have overlapping parts",
+                );
+
+                Substitution { parts }
+            })
+            .collect();
 
         self.push_suggestion(CodeSuggestion {
-            substitutions: suggestions
-                .into_iter()
-                .map(|sugg| Substitution {
-                    parts: sugg
-                        .into_iter()
-                        .map(|(span, snippet)| SubstitutionPart { snippet, span })
-                        .collect(),
-                })
-                .collect(),
+            substitutions,
             msg: self.subdiagnostic_message_to_diagnostic_message(msg),
             style: SuggestionStyle::ShowCode,
             applicability,
@@ -1034,6 +1038,7 @@ impl Diagnostic {
     ) -> (
         &Level,
         &[(DiagnosticMessage, Style)],
+        Vec<(&Cow<'static, str>, &DiagnosticArgValue<'static>)>,
         &Option<DiagnosticId>,
         &MultiSpan,
         &Result<Vec<CodeSuggestion>, SuggestionsDisabled>,
@@ -1042,6 +1047,7 @@ impl Diagnostic {
         (
             &self.level,
             &self.message,
+            self.args().collect(),
             &self.code,
             &self.span,
             &self.suggestions,
diff --git a/compiler/rustc_errors/src/diagnostic_builder.rs b/compiler/rustc_errors/src/diagnostic_builder.rs
index cbfee582d..3064d2bed 100644
--- a/compiler/rustc_errors/src/diagnostic_builder.rs
+++ b/compiler/rustc_errors/src/diagnostic_builder.rs
@@ -408,6 +408,59 @@ impl EmissionGuarantee for ! {
     }
 }
 
+impl<'a> DiagnosticBuilder<'a, rustc_span::fatal_error::FatalError> {
+    /// Convenience function for internal use, clients should use one of the
+    /// `struct_*` methods on [`Handler`].
+    #[track_caller]
+    pub(crate) fn new_almost_fatal(
+        handler: &'a Handler,
+        message: impl Into<DiagnosticMessage>,
+    ) -> Self {
+        let diagnostic = Diagnostic::new_with_code(Level::Fatal, None, message);
+        Self::new_diagnostic_almost_fatal(handler, diagnostic)
+    }
+
+    /// Creates a new `DiagnosticBuilder` with an already constructed
+    /// diagnostic.
+    pub(crate) fn new_diagnostic_almost_fatal(
+        handler: &'a Handler,
+        diagnostic: Diagnostic,
+    ) -> Self {
+        debug!("Created new diagnostic");
+        Self {
+            inner: DiagnosticBuilderInner {
+                state: DiagnosticBuilderState::Emittable(handler),
+                diagnostic: Box::new(diagnostic),
+            },
+            _marker: PhantomData,
+        }
+    }
+}
+
+impl EmissionGuarantee for rustc_span::fatal_error::FatalError {
+    fn diagnostic_builder_emit_producing_guarantee(db: &mut DiagnosticBuilder<'_, Self>) -> Self {
+        match db.inner.state {
+            // First `.emit()` call, the `&Handler` is still available.
+            DiagnosticBuilderState::Emittable(handler) => {
+                db.inner.state = DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation;
+
+                handler.emit_diagnostic(&mut db.inner.diagnostic);
+            }
+            // `.emit()` was previously called, disallowed from repeating it.
+            DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation => {}
+        }
+        // Then fatally error..
+        rustc_span::fatal_error::FatalError
+    }
+
+    fn make_diagnostic_builder(
+        handler: &Handler,
+        msg: impl Into<DiagnosticMessage>,
+    ) -> DiagnosticBuilder<'_, Self> {
+        DiagnosticBuilder::new_almost_fatal(handler, msg)
+    }
+}
+
 /// In general, the `DiagnosticBuilder` uses deref to allow access to
 /// the fields and methods of the embedded `diagnostic` in a
 /// transparent way. *However,* many of the methods are intended to
@@ -616,7 +669,6 @@ impl<'a, G: EmissionGuarantee> DiagnosticBuilder<'a, G> {
         sp: impl Into<MultiSpan>,
         msg: impl Into<SubdiagnosticMessage>,
     ) -> &mut Self);
-    forward!(pub fn help_use_latest_edition(&mut self,) -> &mut Self);
     forward!(pub fn set_is_lint(&mut self,) -> &mut Self);
 
     forward!(pub fn disable_suggestions(&mut self,) -> &mut Self);
diff --git a/compiler/rustc_errors/src/diagnostic_impls.rs b/compiler/rustc_errors/src/diagnostic_impls.rs
index dad5e98aa..e82bad67b 100644
--- a/compiler/rustc_errors/src/diagnostic_impls.rs
+++ b/compiler/rustc_errors/src/diagnostic_impls.rs
@@ -1,6 +1,5 @@
-use crate::{
-    fluent, DiagnosticArgValue, DiagnosticBuilder, Handler, IntoDiagnostic, IntoDiagnosticArg,
-};
+use crate::fluent_generated as fluent;
+use crate::{DiagnosticArgValue, DiagnosticBuilder, Handler, IntoDiagnostic, IntoDiagnosticArg};
 use rustc_ast as ast;
 use rustc_ast_pretty::pprust;
 use rustc_hir as hir;
@@ -36,6 +35,12 @@ impl<'a, T: fmt::Display> From<&'a T> for DiagnosticArgFromDisplay<'a> {
     }
 }
 
+impl<'a, T: Clone + IntoDiagnosticArg> IntoDiagnosticArg for &'a T {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        self.clone().into_diagnostic_arg()
+    }
+}
+
 macro_rules! into_diagnostic_arg_using_display {
     ($( $ty:ty ),+ $(,)?) => {
         $(
@@ -49,6 +54,7 @@ macro_rules! into_diagnostic_arg_using_display {
 }
 
 into_diagnostic_arg_using_display!(
+    ast::ParamKindOrd,
     i8,
     u8,
     i16,
@@ -153,12 +159,6 @@ impl IntoDiagnosticArg for ast::Path {
     }
 }
 
-impl IntoDiagnosticArg for &ast::Path {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(pprust::path_to_string(self)))
-    }
-}
-
 impl IntoDiagnosticArg for ast::token::Token {
     fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
         DiagnosticArgValue::Str(pprust::token_to_string(&self))
@@ -177,6 +177,26 @@ impl IntoDiagnosticArg for type_ir::FloatTy {
     }
 }
 
+impl IntoDiagnosticArg for std::ffi::CString {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.to_string_lossy().into_owned()))
+    }
+}
+
+impl IntoDiagnosticArg for rustc_data_structures::small_c_str::SmallCStr {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.to_string_lossy().into_owned()))
+    }
+}
+
+impl IntoDiagnosticArg for ast::Visibility {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        let s = pprust::vis_to_string(&self);
+        let s = s.trim_end().to_string();
+        DiagnosticArgValue::Str(Cow::Owned(s))
+    }
+}
+
 impl IntoDiagnosticArg for Level {
     fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
         DiagnosticArgValue::Str(Cow::Borrowed(self.to_cmd_flag()))
diff --git a/compiler/rustc_errors/src/emitter.rs b/compiler/rustc_errors/src/emitter.rs
index 628e19999..211bbf4f5 100644
--- a/compiler/rustc_errors/src/emitter.rs
+++ b/compiler/rustc_errors/src/emitter.rs
@@ -18,7 +18,7 @@ use crate::translation::{to_fluent_args, Translate};
 use crate::{
     diagnostic::DiagnosticLocation, CodeSuggestion, Diagnostic, DiagnosticId, DiagnosticMessage,
     FluentBundle, Handler, LazyFallbackBundle, Level, MultiSpan, SubDiagnostic,
-    SubstitutionHighlight, SuggestionStyle,
+    SubstitutionHighlight, SuggestionStyle, TerminalUrl,
 };
 use rustc_lint_defs::pluralize;
 
@@ -66,6 +66,7 @@ impl HumanReadableErrorType {
         diagnostic_width: Option<usize>,
         macro_backtrace: bool,
         track_diagnostics: bool,
+        terminal_url: TerminalUrl,
     ) -> EmitterWriter {
         let (short, color_config) = self.unzip();
         let color = color_config.suggests_using_colors();
@@ -80,6 +81,7 @@ impl HumanReadableErrorType {
             diagnostic_width,
             macro_backtrace,
             track_diagnostics,
+            terminal_url,
         )
     }
 }
@@ -652,6 +654,7 @@ pub struct EmitterWriter {
 
     macro_backtrace: bool,
     track_diagnostics: bool,
+    terminal_url: TerminalUrl,
 }
 
 #[derive(Debug)]
@@ -672,6 +675,7 @@ impl EmitterWriter {
         diagnostic_width: Option<usize>,
         macro_backtrace: bool,
         track_diagnostics: bool,
+        terminal_url: TerminalUrl,
     ) -> EmitterWriter {
         let dst = Destination::from_stderr(color_config);
         EmitterWriter {
@@ -685,6 +689,7 @@ impl EmitterWriter {
             diagnostic_width,
             macro_backtrace,
             track_diagnostics,
+            terminal_url,
         }
     }
 
@@ -699,6 +704,7 @@ impl EmitterWriter {
         diagnostic_width: Option<usize>,
         macro_backtrace: bool,
         track_diagnostics: bool,
+        terminal_url: TerminalUrl,
     ) -> EmitterWriter {
         EmitterWriter {
             dst: Raw(dst, colored),
@@ -711,6 +717,7 @@ impl EmitterWriter {
             diagnostic_width,
             macro_backtrace,
             track_diagnostics,
+            terminal_url,
         }
     }
 
@@ -1378,7 +1385,13 @@ impl EmitterWriter {
             // only render error codes, not lint codes
             if let Some(DiagnosticId::Error(ref code)) = *code {
                 buffer.append(0, "[", Style::Level(*level));
-                buffer.append(0, code, Style::Level(*level));
+                let code = if let TerminalUrl::Yes = self.terminal_url {
+                    let path = "https://doc.rust-lang.org/error_codes";
+                    format!("\x1b]8;;{path}/{code}.html\x07{code}\x1b]8;;\x07")
+                } else {
+                    code.clone()
+                };
+                buffer.append(0, &code, Style::Level(*level));
                 buffer.append(0, "]", Style::Level(*level));
                 label_width += 2 + code.len();
             }
@@ -1755,7 +1768,7 @@ impl EmitterWriter {
 
         // Render the replacements for each suggestion
         let suggestions = suggestion.splice_lines(sm);
-        debug!("emit_suggestion_default: suggestions={:?}", suggestions);
+        debug!(?suggestions);
 
         if suggestions.is_empty() {
             // Suggestions coming from macros can have malformed spans. This is a heavy handed
@@ -1784,6 +1797,7 @@ impl EmitterWriter {
         for (complete, parts, highlights, only_capitalization) in
             suggestions.iter().take(MAX_SUGGESTIONS)
         {
+            debug!(?complete, ?parts, ?highlights);
             notice_capitalization |= only_capitalization;
 
             let has_deletion = parts.iter().any(|p| p.is_deletion(sm));
@@ -1796,17 +1810,17 @@ impl EmitterWriter {
                 // telling users to make a change but not clarifying *where*.
                 let loc = sm.lookup_char_pos(parts[0].span.lo());
                 if loc.file.name != sm.span_to_filename(span) && loc.file.name.is_real() {
-                    buffer.puts(row_num - 1, 0, "--> ", Style::LineNumber);
-                    buffer.append(
-                        row_num - 1,
-                        &format!(
-                            "{}:{}:{}",
-                            sm.filename_for_diagnostics(&loc.file.name),
-                            sm.doctest_offset_line(&loc.file.name, loc.line),
-                            loc.col.0 + 1,
-                        ),
-                        Style::LineAndColumn,
-                    );
+                    let arrow = "--> ";
+                    buffer.puts(row_num - 1, 0, arrow, Style::LineNumber);
+                    let filename = sm.filename_for_diagnostics(&loc.file.name);
+                    let offset = sm.doctest_offset_line(&loc.file.name, loc.line);
+                    let message = format!("{}:{}:{}", filename, offset, loc.col.0 + 1);
+                    if row_num == 2 {
+                        let col = usize::max(max_line_num_len + 1, arrow.len());
+                        buffer.puts(1, col, &message, Style::LineAndColumn);
+                    } else {
+                        buffer.append(row_num - 1, &message, Style::LineAndColumn);
+                    }
                     for _ in 0..max_line_num_len {
                         buffer.prepend(row_num - 1, " ", Style::NoStyle);
                     }
@@ -1882,9 +1896,8 @@ impl EmitterWriter {
                             &mut buffer,
                             &mut row_num,
                             &Vec::new(),
-                            p,
+                            p + line_start,
                             l,
-                            line_start,
                             show_code_change,
                             max_line_num_len,
                             &file_lines,
@@ -1907,9 +1920,8 @@ impl EmitterWriter {
                                 &mut buffer,
                                 &mut row_num,
                                 &Vec::new(),
-                                p,
+                                p + line_start,
                                 l,
-                                line_start,
                                 show_code_change,
                                 max_line_num_len,
                                 &file_lines,
@@ -1925,9 +1937,8 @@ impl EmitterWriter {
                                 &mut buffer,
                                 &mut row_num,
                                 &Vec::new(),
-                                p,
+                                p + line_start,
                                 l,
-                                line_start,
                                 show_code_change,
                                 max_line_num_len,
                                 &file_lines,
@@ -1941,9 +1952,8 @@ impl EmitterWriter {
                     &mut buffer,
                     &mut row_num,
                     highlight_parts,
-                    line_pos,
+                    line_pos + line_start,
                     line,
-                    line_start,
                     show_code_change,
                     max_line_num_len,
                     &file_lines,
@@ -2113,30 +2123,38 @@ impl EmitterWriter {
                         }
                     }
                     for sugg in suggestions {
-                        if sugg.style == SuggestionStyle::CompletelyHidden {
-                            // do not display this suggestion, it is meant only for tools
-                        } else if sugg.style == SuggestionStyle::HideCodeAlways {
-                            if let Err(e) = self.emit_message_default(
-                                &MultiSpan::new(),
-                                &[(sugg.msg.to_owned(), Style::HeaderMsg)],
-                                args,
-                                &None,
-                                &Level::Help,
-                                max_line_num_len,
-                                true,
-                                None,
-                            ) {
-                                panic!("failed to emit error: {}", e);
+                        match sugg.style {
+                            SuggestionStyle::CompletelyHidden => {
+                                // do not display this suggestion, it is meant only for tools
                             }
-                        } else if let Err(e) = self.emit_suggestion_default(
-                            span,
-                            sugg,
-                            args,
-                            &Level::Help,
-                            max_line_num_len,
-                        ) {
-                            panic!("failed to emit error: {}", e);
-                        };
+                            SuggestionStyle::HideCodeAlways => {
+                                if let Err(e) = self.emit_message_default(
+                                    &MultiSpan::new(),
+                                    &[(sugg.msg.to_owned(), Style::HeaderMsg)],
+                                    args,
+                                    &None,
+                                    &Level::Help,
+                                    max_line_num_len,
+                                    true,
+                                    None,
+                                ) {
+                                    panic!("failed to emit error: {}", e);
+                                }
+                            }
+                            SuggestionStyle::HideCodeInline
+                            | SuggestionStyle::ShowCode
+                            | SuggestionStyle::ShowAlways => {
+                                if let Err(e) = self.emit_suggestion_default(
+                                    span,
+                                    sugg,
+                                    args,
+                                    &Level::Help,
+                                    max_line_num_len,
+                                ) {
+                                    panic!("failed to emit error: {}", e);
+                                }
+                            }
+                        }
                     }
                 }
             }
@@ -2159,40 +2177,63 @@ impl EmitterWriter {
         buffer: &mut StyledBuffer,
         row_num: &mut usize,
         highlight_parts: &Vec<SubstitutionHighlight>,
-        line_pos: usize,
-        line: &str,
-        line_start: usize,
+        line_num: usize,
+        line_to_add: &str,
         show_code_change: DisplaySuggestion,
         max_line_num_len: usize,
         file_lines: &FileLines,
         is_multiline: bool,
     ) {
-        // Print the span column to avoid confusion
-        buffer.puts(*row_num, 0, &self.maybe_anonymized(line_start + line_pos), Style::LineNumber);
         if let DisplaySuggestion::Diff = show_code_change {
-            // Add the line number for both addition and removal to drive the point home.
-            //
-            // N - fn foo<A: T>(bar: A) {
-            // N + fn foo(bar: impl T) {
-            buffer.puts(
-                *row_num - 1,
-                0,
-                &self.maybe_anonymized(line_start + line_pos),
-                Style::LineNumber,
-            );
-            buffer.puts(*row_num - 1, max_line_num_len + 1, "- ", Style::Removal);
-            buffer.puts(
-                *row_num - 1,
-                max_line_num_len + 3,
-                &normalize_whitespace(
-                    &file_lines.file.get_line(file_lines.lines[line_pos].line_index).unwrap(),
-                ),
-                Style::NoStyle,
-            );
-            buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition);
+            // We need to print more than one line if the span we need to remove is multiline.
+            // For more info: https://github.com/rust-lang/rust/issues/92741
+            let lines_to_remove = file_lines.lines.iter().take(file_lines.lines.len() - 1);
+            for (index, line_to_remove) in lines_to_remove.enumerate() {
+                buffer.puts(
+                    *row_num - 1,
+                    0,
+                    &self.maybe_anonymized(line_num + index),
+                    Style::LineNumber,
+                );
+                buffer.puts(*row_num - 1, max_line_num_len + 1, "- ", Style::Removal);
+                let line = normalize_whitespace(
+                    &file_lines.file.get_line(line_to_remove.line_index).unwrap(),
+                );
+                buffer.puts(*row_num - 1, max_line_num_len + 3, &line, Style::NoStyle);
+                *row_num += 1;
+            }
+            // If the last line is exactly equal to the line we need to add, we can skip both of them.
+            // This allows us to avoid output like the following:
+            // 2 - &
+            // 2 + if true { true } else { false }
+            // 3 - if true { true } else { false }
+            // If those lines aren't equal, we print their diff
+            let last_line_index = file_lines.lines[file_lines.lines.len() - 1].line_index;
+            let last_line = &file_lines.file.get_line(last_line_index).unwrap();
+            if last_line != line_to_add {
+                buffer.puts(
+                    *row_num - 1,
+                    0,
+                    &self.maybe_anonymized(line_num + file_lines.lines.len() - 1),
+                    Style::LineNumber,
+                );
+                buffer.puts(*row_num - 1, max_line_num_len + 1, "- ", Style::Removal);
+                buffer.puts(
+                    *row_num - 1,
+                    max_line_num_len + 3,
+                    &normalize_whitespace(last_line),
+                    Style::NoStyle,
+                );
+                buffer.puts(*row_num, 0, &self.maybe_anonymized(line_num), Style::LineNumber);
+                buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition);
+                buffer.append(*row_num, &normalize_whitespace(line_to_add), Style::NoStyle);
+            } else {
+                *row_num -= 2;
+            }
         } else if is_multiline {
+            buffer.puts(*row_num, 0, &self.maybe_anonymized(line_num), Style::LineNumber);
             match &highlight_parts[..] {
-                [SubstitutionHighlight { start: 0, end }] if *end == line.len() => {
+                [SubstitutionHighlight { start: 0, end }] if *end == line_to_add.len() => {
                     buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition);
                 }
                 [] => {
@@ -2202,17 +2243,17 @@ impl EmitterWriter {
                     buffer.puts(*row_num, max_line_num_len + 1, "~ ", Style::Addition);
                 }
             }
+            buffer.append(*row_num, &normalize_whitespace(line_to_add), Style::NoStyle);
         } else {
+            buffer.puts(*row_num, 0, &self.maybe_anonymized(line_num), Style::LineNumber);
             draw_col_separator(buffer, *row_num, max_line_num_len + 1);
+            buffer.append(*row_num, &normalize_whitespace(line_to_add), Style::NoStyle);
         }
 
-        // print the suggestion
-        buffer.append(*row_num, &normalize_whitespace(line), Style::NoStyle);
-
         // Colorize addition/replacements with green.
         for &SubstitutionHighlight { start, end } in highlight_parts {
             // Account for tabs when highlighting (#87972).
-            let tabs: usize = line
+            let tabs: usize = line_to_add
                 .chars()
                 .take(start)
                 .map(|ch| match ch {
diff --git a/compiler/rustc_errors/src/json.rs b/compiler/rustc_errors/src/json.rs
index dc38b8725..f32d6b96b 100644
--- a/compiler/rustc_errors/src/json.rs
+++ b/compiler/rustc_errors/src/json.rs
@@ -17,6 +17,7 @@ use crate::translation::{to_fluent_args, Translate};
 use crate::DiagnosticId;
 use crate::{
     CodeSuggestion, FluentBundle, LazyFallbackBundle, MultiSpan, SpanLabel, SubDiagnostic,
+    TerminalUrl,
 };
 use rustc_lint_defs::Applicability;
 
@@ -47,6 +48,7 @@ pub struct JsonEmitter {
     diagnostic_width: Option<usize>,
     macro_backtrace: bool,
     track_diagnostics: bool,
+    terminal_url: TerminalUrl,
 }
 
 impl JsonEmitter {
@@ -60,6 +62,7 @@ impl JsonEmitter {
         diagnostic_width: Option<usize>,
         macro_backtrace: bool,
         track_diagnostics: bool,
+        terminal_url: TerminalUrl,
     ) -> JsonEmitter {
         JsonEmitter {
             dst: Box::new(io::BufWriter::new(io::stderr())),
@@ -73,6 +76,7 @@ impl JsonEmitter {
             diagnostic_width,
             macro_backtrace,
             track_diagnostics,
+            terminal_url,
         }
     }
 
@@ -84,6 +88,7 @@ impl JsonEmitter {
         diagnostic_width: Option<usize>,
         macro_backtrace: bool,
         track_diagnostics: bool,
+        terminal_url: TerminalUrl,
     ) -> JsonEmitter {
         let file_path_mapping = FilePathMapping::empty();
         JsonEmitter::stderr(
@@ -96,6 +101,7 @@ impl JsonEmitter {
             diagnostic_width,
             macro_backtrace,
             track_diagnostics,
+            terminal_url,
         )
     }
 
@@ -110,6 +116,7 @@ impl JsonEmitter {
         diagnostic_width: Option<usize>,
         macro_backtrace: bool,
         track_diagnostics: bool,
+        terminal_url: TerminalUrl,
     ) -> JsonEmitter {
         JsonEmitter {
             dst,
@@ -123,6 +130,7 @@ impl JsonEmitter {
             diagnostic_width,
             macro_backtrace,
             track_diagnostics,
+            terminal_url,
         }
     }
 
@@ -360,6 +368,7 @@ impl Diagnostic {
                 je.diagnostic_width,
                 je.macro_backtrace,
                 je.track_diagnostics,
+                je.terminal_url,
             )
             .ui_testing(je.ui_testing)
             .emit_diagnostic(diag);
@@ -571,7 +580,7 @@ impl DiagnosticCode {
             let je_result =
                 je.registry.as_ref().map(|registry| registry.try_find_description(&s)).unwrap();
 
-            DiagnosticCode { code: s, explanation: je_result.unwrap_or(None) }
+            DiagnosticCode { code: s, explanation: je_result.ok() }
         })
     }
 }
diff --git a/compiler/rustc_errors/src/json/tests.rs b/compiler/rustc_errors/src/json/tests.rs
index f13146897..671dc449e 100644
--- a/compiler/rustc_errors/src/json/tests.rs
+++ b/compiler/rustc_errors/src/json/tests.rs
@@ -4,7 +4,7 @@ use crate::json::JsonEmitter;
 use rustc_span::source_map::{FilePathMapping, SourceMap};
 
 use crate::emitter::{ColorConfig, HumanReadableErrorType};
-use crate::Handler;
+use crate::{Handler, TerminalUrl};
 use rustc_span::{BytePos, Span};
 
 use std::str;
@@ -46,7 +46,7 @@ fn test_positions(code: &str, span: (u32, u32), expected_output: SpanTestData) {
         let sm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
         sm.new_source_file(Path::new("test.rs").to_owned().into(), code.to_owned());
         let fallback_bundle =
-            crate::fallback_fluent_bundle(rustc_error_messages::DEFAULT_LOCALE_RESOURCES, false);
+            crate::fallback_fluent_bundle(vec![crate::DEFAULT_LOCALE_RESOURCE], false);
 
         let output = Arc::new(Mutex::new(Vec::new()));
         let je = JsonEmitter::new(
@@ -60,6 +60,7 @@ fn test_positions(code: &str, span: (u32, u32), expected_output: SpanTestData) {
             None,
             false,
             false,
+            TerminalUrl::No,
         );
 
         let span = Span::with_root_ctxt(BytePos(span.0), BytePos(span.1));
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index 535812fb0..09bf28ed4 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -3,6 +3,7 @@
 //! This module contains the code for creating and emitting diagnostics.
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
+#![feature(array_windows)]
 #![feature(drain_filter)]
 #![feature(if_let_guard)]
 #![feature(is_terminal)]
@@ -35,13 +36,13 @@ use rustc_data_structures::stable_hasher::StableHasher;
 use rustc_data_structures::sync::{self, Lock, Lrc};
 use rustc_data_structures::AtomicRef;
 pub use rustc_error_messages::{
-    fallback_fluent_bundle, fluent, fluent_bundle, DelayDm, DiagnosticMessage, FluentBundle,
+    fallback_fluent_bundle, fluent_bundle, DelayDm, DiagnosticMessage, FluentBundle,
     LanguageIdentifier, LazyFallbackBundle, MultiSpan, SpanLabel, SubdiagnosticMessage,
-    DEFAULT_LOCALE_RESOURCES,
 };
 pub use rustc_lint_defs::{pluralize, Applicability};
+use rustc_macros::fluent_messages;
 use rustc_span::source_map::SourceMap;
-use rustc_span::HashStableContext;
+pub use rustc_span::ErrorGuaranteed;
 use rustc_span::{Loc, Span};
 
 use std::borrow::Cow;
@@ -75,6 +76,8 @@ pub use snippet::Style;
 pub type PErr<'a> = DiagnosticBuilder<'a, ErrorGuaranteed>;
 pub type PResult<'a, T> = Result<T, PErr<'a>>;
 
+fluent_messages! { "../locales/en-US.ftl" }
+
 // `PResult` is used a lot. Make sure it doesn't unintentionally get bigger.
 // (See also the comment on `DiagnosticBuilderInner`'s `diagnostic` field.)
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
@@ -572,6 +575,7 @@ impl Handler {
             None,
             flags.macro_backtrace,
             flags.track_diagnostics,
+            TerminalUrl::No,
         ));
         Self::with_emitter_and_flags(emitter, flags)
     }
@@ -616,22 +620,24 @@ impl Handler {
         }
     }
 
-    /// Translate `message` eagerly with `args`.
+    /// Translate `message` eagerly with `args` to `SubdiagnosticMessage::Eager`.
     pub fn eagerly_translate<'a>(
         &self,
         message: DiagnosticMessage,
         args: impl Iterator<Item = DiagnosticArg<'a, 'static>>,
     ) -> SubdiagnosticMessage {
+        SubdiagnosticMessage::Eager(self.eagerly_translate_to_string(message, args))
+    }
+
+    /// Translate `message` eagerly with `args` to `String`.
+    pub fn eagerly_translate_to_string<'a>(
+        &self,
+        message: DiagnosticMessage,
+        args: impl Iterator<Item = DiagnosticArg<'a, 'static>>,
+    ) -> String {
         let inner = self.inner.borrow();
         let args = crate::translation::to_fluent_args(args);
-        SubdiagnosticMessage::Eager(
-            inner
-                .emitter
-                .translate_message(&message, &args)
-                .map_err(Report::new)
-                .unwrap()
-                .to_string(),
-        )
+        inner.emitter.translate_message(&message, &args).map_err(Report::new).unwrap().to_string()
     }
 
     // This is here to not allow mutation of flags;
@@ -1009,6 +1015,7 @@ impl Handler {
     }
 
     #[track_caller]
+    #[rustc_lint_diagnostics]
     pub fn span_note_without_error(
         &self,
         span: impl Into<MultiSpan>,
@@ -1018,6 +1025,7 @@ impl Handler {
     }
 
     #[track_caller]
+    #[rustc_lint_diagnostics]
     pub fn span_note_diag(
         &self,
         span: Span,
@@ -1029,19 +1037,23 @@ impl Handler {
     }
 
     // NOTE: intentionally doesn't raise an error so rustc_codegen_ssa only reports fatal errors in the main thread
+    #[rustc_lint_diagnostics]
     pub fn fatal(&self, msg: impl Into<DiagnosticMessage>) -> FatalError {
         self.inner.borrow_mut().fatal(msg)
     }
 
+    #[rustc_lint_diagnostics]
     pub fn err(&self, msg: impl Into<DiagnosticMessage>) -> ErrorGuaranteed {
         self.inner.borrow_mut().err(msg)
     }
 
+    #[rustc_lint_diagnostics]
     pub fn warn(&self, msg: impl Into<DiagnosticMessage>) {
         let mut db = DiagnosticBuilder::new(self, Warning(None), msg);
         db.emit();
     }
 
+    #[rustc_lint_diagnostics]
     pub fn note_without_error(&self, msg: impl Into<DiagnosticMessage>) {
         DiagnosticBuilder::new(self, Note, msg).emit();
     }
@@ -1056,28 +1068,26 @@ impl Handler {
     }
 
     pub fn has_errors(&self) -> Option<ErrorGuaranteed> {
-        if self.inner.borrow().has_errors() { Some(ErrorGuaranteed(())) } else { None }
+        self.inner.borrow().has_errors().then(ErrorGuaranteed::unchecked_claim_error_was_emitted)
     }
+
     pub fn has_errors_or_lint_errors(&self) -> Option<ErrorGuaranteed> {
-        if self.inner.borrow().has_errors_or_lint_errors() {
-            Some(ErrorGuaranteed::unchecked_claim_error_was_emitted())
-        } else {
-            None
-        }
+        self.inner
+            .borrow()
+            .has_errors_or_lint_errors()
+            .then(ErrorGuaranteed::unchecked_claim_error_was_emitted)
     }
     pub fn has_errors_or_delayed_span_bugs(&self) -> Option<ErrorGuaranteed> {
-        if self.inner.borrow().has_errors_or_delayed_span_bugs() {
-            Some(ErrorGuaranteed::unchecked_claim_error_was_emitted())
-        } else {
-            None
-        }
+        self.inner
+            .borrow()
+            .has_errors_or_delayed_span_bugs()
+            .then(ErrorGuaranteed::unchecked_claim_error_was_emitted)
     }
     pub fn is_compilation_going_to_fail(&self) -> Option<ErrorGuaranteed> {
-        if self.inner.borrow().is_compilation_going_to_fail() {
-            Some(ErrorGuaranteed::unchecked_claim_error_was_emitted())
-        } else {
-            None
-        }
+        self.inner
+            .borrow()
+            .is_compilation_going_to_fail()
+            .then(ErrorGuaranteed::unchecked_claim_error_was_emitted)
     }
 
     pub fn print_error_count(&self, registry: &Registry) {
@@ -1131,6 +1141,20 @@ impl Handler {
         self.create_warning(warning).emit()
     }
 
+    pub fn create_almost_fatal<'a>(
+        &'a self,
+        fatal: impl IntoDiagnostic<'a, FatalError>,
+    ) -> DiagnosticBuilder<'a, FatalError> {
+        fatal.into_diagnostic(self)
+    }
+
+    pub fn emit_almost_fatal<'a>(
+        &'a self,
+        fatal: impl IntoDiagnostic<'a, FatalError>,
+    ) -> FatalError {
+        self.create_almost_fatal(fatal).emit()
+    }
+
     pub fn create_fatal<'a>(
         &'a self,
         fatal: impl IntoDiagnostic<'a, !>,
@@ -1156,6 +1180,17 @@ impl Handler {
         self.create_bug(bug).emit()
     }
 
+    pub fn emit_note<'a>(&'a self, note: impl IntoDiagnostic<'a, Noted>) -> Noted {
+        self.create_note(note).emit()
+    }
+
+    pub fn create_note<'a>(
+        &'a self,
+        note: impl IntoDiagnostic<'a, Noted>,
+    ) -> DiagnosticBuilder<'a, Noted> {
+        note.into_diagnostic(self)
+    }
+
     fn emit_diag_at_span(
         &self,
         mut diag: Diagnostic,
@@ -1440,9 +1475,7 @@ impl HandlerInner {
                 .emitted_diagnostic_codes
                 .iter()
                 .filter_map(|x| match &x {
-                    DiagnosticId::Error(s)
-                        if registry.try_find_description(s).map_or(false, |o| o.is_some()) =>
-                    {
+                    DiagnosticId::Error(s) if registry.try_find_description(s).is_ok() => {
                         Some(s.clone())
                     }
                     _ => None,
@@ -1803,16 +1836,9 @@ pub fn add_elided_lifetime_in_path_suggestion(
     );
 }
 
-/// Useful type to use with `Result<>` indicate that an error has already
-/// been reported to the user, so no need to continue checking.
-#[derive(Clone, Copy, Debug, Encodable, Decodable, Hash, PartialEq, Eq, PartialOrd, Ord)]
-#[derive(HashStable_Generic)]
-pub struct ErrorGuaranteed(());
-
-impl ErrorGuaranteed {
-    /// To be used only if you really know what you are doing... ideally, we would find a way to
-    /// eliminate all calls to this method.
-    pub fn unchecked_claim_error_was_emitted() -> Self {
-        ErrorGuaranteed(())
-    }
+#[derive(Clone, Copy, PartialEq, Hash, Debug)]
+pub enum TerminalUrl {
+    No,
+    Yes,
+    Auto,
 }
diff --git a/compiler/rustc_errors/src/registry.rs b/compiler/rustc_errors/src/registry.rs
index da764d993..f26d8e7eb 100644
--- a/compiler/rustc_errors/src/registry.rs
+++ b/compiler/rustc_errors/src/registry.rs
@@ -5,21 +5,17 @@ pub struct InvalidErrorCode;
 
 #[derive(Clone)]
 pub struct Registry {
-    long_descriptions: FxHashMap<&'static str, Option<&'static str>>,
+    long_descriptions: FxHashMap<&'static str, &'static str>,
 }
 
 impl Registry {
-    pub fn new(long_descriptions: &[(&'static str, Option<&'static str>)]) -> Registry {
+    pub fn new(long_descriptions: &[(&'static str, &'static str)]) -> Registry {
         Registry { long_descriptions: long_descriptions.iter().copied().collect() }
     }
 
     /// Returns `InvalidErrorCode` if the code requested does not exist in the
-    /// registry. Otherwise, returns an `Option` where `None` means the error
-    /// code is valid but has no extended information.
-    pub fn try_find_description(
-        &self,
-        code: &str,
-    ) -> Result<Option<&'static str>, InvalidErrorCode> {
+    /// registry.
+    pub fn try_find_description(&self, code: &str) -> Result<&'static str, InvalidErrorCode> {
         self.long_descriptions.get(code).copied().ok_or(InvalidErrorCode)
     }
 }
diff --git a/compiler/rustc_errors/src/styled_buffer.rs b/compiler/rustc_errors/src/styled_buffer.rs
index 9abdb5fc9..9aa14e1f2 100644
--- a/compiler/rustc_errors/src/styled_buffer.rs
+++ b/compiler/rustc_errors/src/styled_buffer.rs
@@ -142,7 +142,7 @@ impl StyledBuffer {
     pub fn set_style(&mut self, line: usize, col: usize, style: Style, overwrite: bool) {
         if let Some(ref mut line) = self.lines.get_mut(line) {
             if let Some(StyledChar { style: s, .. }) = line.get_mut(col) {
-                if overwrite || *s == Style::NoStyle || *s == Style::Quotation {
+                if overwrite || matches!(s, Style::NoStyle | Style::Quotation) {
                     *s = style;
                 }
             }
diff --git a/compiler/rustc_errors/src/translation.rs b/compiler/rustc_errors/src/translation.rs
index addfc9726..ed35eb1b6 100644
--- a/compiler/rustc_errors/src/translation.rs
+++ b/compiler/rustc_errors/src/translation.rs
@@ -1,9 +1,10 @@
-use crate::error::TranslateError;
+use crate::error::{TranslateError, TranslateErrorKind};
 use crate::snippet::Style;
 use crate::{DiagnosticArg, DiagnosticMessage, FluentBundle};
 use rustc_data_structures::sync::Lrc;
 use rustc_error_messages::FluentArgs;
 use std::borrow::Cow;
+use std::env;
 use std::error::Report;
 
 /// Convert diagnostic arguments (a rustc internal type that exists to implement
@@ -94,12 +95,29 @@ pub trait Translate {
                 // The primary bundle was present and translation succeeded
                 Some(Ok(t)) => t,
 
-                // Always yeet out for errors on debug
-                Some(Err(primary)) if cfg!(debug_assertions) => do yeet primary,
-
                 // If `translate_with_bundle` returns `Err` with the primary bundle, this is likely
-                // just that the primary bundle doesn't contain the message being translated or
-                // something else went wrong) so proceed to the fallback bundle.
+                // just that the primary bundle doesn't contain the message being translated, so
+                // proceed to the fallback bundle.
+                Some(Err(
+                    primary @ TranslateError::One {
+                        kind: TranslateErrorKind::MessageMissing, ..
+                    },
+                )) => translate_with_bundle(self.fallback_fluent_bundle())
+                    .map_err(|fallback| primary.and(fallback))?,
+
+                // Always yeet out for errors on debug (unless
+                // `RUSTC_TRANSLATION_NO_DEBUG_ASSERT` is set in the environment - this allows
+                // local runs of the test suites, of builds with debug assertions, to test the
+                // behaviour in a normal build).
+                Some(Err(primary))
+                    if cfg!(debug_assertions)
+                        && env::var("RUSTC_TRANSLATION_NO_DEBUG_ASSERT").is_err() =>
+                {
+                    do yeet primary
+                }
+
+                // ..otherwise, for end users, an error about this wouldn't be useful or actionable, so
+                // just hide it and try with the fallback bundle.
                 Some(Err(primary)) => translate_with_bundle(self.fallback_fluent_bundle())
                     .map_err(|fallback| primary.and(fallback))?,