Auto merge of #106442 - matthiaskrgr:rollup-wivf7gh, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #106200 (Suggest `impl Fn*` and `impl Future` in `-> _` return suggestions)
 - #106274 (Add JSON output to -Zdump-mono-stats)
 - #106292 (Add codegen test for `Box::new(uninit)` of big arrays)
 - #106327 (Add tidy check for dbg)
 - #106361 (Note maximum integer literal for `IntLiteralTooLarge`)
 - #106396 (Allow passing a specific date to `bump-stage0`)
 - #106436 (Enable doctests for rustc_query_impl)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

11 files changed, 194 insertions, 80 deletions

diff --git a/compiler/rustc_ast/src/util/literal.rs b/compiler/rustc_ast/src/util/literal.rs
index 0daeecb53a8..69a9a583048 100644
--- a/compiler/rustc_ast/src/util/literal.rs
+++ b/compiler/rustc_ast/src/util/literal.rs
@@ -34,7 +34,7 @@ pub enum LitError {
     InvalidIntSuffix,
     InvalidFloatSuffix,
     NonDecimalFloat(u32),
-    IntTooLarge,
+    IntTooLarge(u32),
 }
 
 impl LitKind {
@@ -333,6 +333,6 @@ fn integer_lit(symbol: Symbol, suffix: Option<Symbol>) -> Result<LitKind, LitErr
         // but these kinds of errors are already reported by the lexer.
         let from_lexer =
             base < 10 && s.chars().any(|c| c.to_digit(10).map_or(false, |d| d >= base));
-        if from_lexer { LitError::LexerError } else { LitError::IntTooLarge }
+        if from_lexer { LitError::LexerError } else { LitError::IntTooLarge(base) }
     })
 }
diff --git a/compiler/rustc_error_messages/locales/en-US/session.ftl b/compiler/rustc_error_messages/locales/en-US/session.ftl
index ab9e8b6baae..bc37d91a7c6 100644
--- a/compiler/rustc_error_messages/locales/en-US/session.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/session.ftl
@@ -85,6 +85,7 @@ session_invalid_float_literal_suffix = invalid suffix `{$suffix}` for float lite
     .help = valid suffixes are `f32` and `f64`
 
 session_int_literal_too_large = integer literal is too large
+    .note = value exceeds limit of `{$limit}`
 
 session_invalid_int_literal_width = invalid width `{$width}` for integer literal
     .help = valid widths are 8, 16, 32, 64 and 128
diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs
index 1ff7429e415..cf847047c90 100644
--- a/compiler/rustc_hir_analysis/src/collect.rs
+++ b/compiler/rustc_hir_analysis/src/collect.rs
@@ -17,6 +17,7 @@
 use crate::astconv::AstConv;
 use crate::check::intrinsic::intrinsic_operation_unsafety;
 use crate::errors;
+use hir::def::DefKind;
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed, StashKey};
@@ -24,8 +25,8 @@ use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{GenericParamKind, Node};
-use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_infer::infer::TyCtxtInferExt;
+use rustc_infer::traits::ObligationCause;
 use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::util::{Discr, IntTypeExt};
@@ -1195,12 +1196,11 @@ fn infer_return_ty_for_fn_sig<'tcx>(
                 ty::ReErased => tcx.lifetimes.re_static,
                 _ => r,
             });
-            let fn_sig = ty::Binder::dummy(fn_sig);
 
             let mut visitor = HirPlaceholderCollector::default();
             visitor.visit_ty(ty);
             let mut diag = bad_placeholder(tcx, visitor.0, "return type");
-            let ret_ty = fn_sig.skip_binder().output();
+            let ret_ty = fn_sig.output();
             if ret_ty.is_suggestable(tcx, false) {
                 diag.span_suggestion(
                     ty.span,
@@ -1223,26 +1223,26 @@ fn infer_return_ty_for_fn_sig<'tcx>(
                         Applicability::MachineApplicable,
                     );
                 }
+            } else if let Some(sugg) = suggest_impl_trait(tcx, ret_ty, ty.span, hir_id, def_id) {
+                diag.span_suggestion(
+                    ty.span,
+                    "replace with an appropriate return type",
+                    sugg,
+                    Applicability::MachineApplicable,
+                );
             } else if ret_ty.is_closure() {
-                // We're dealing with a closure, so we should suggest using `impl Fn` or trait bounds
-                // to prevent the user from getting a papercut while trying to use the unique closure
-                // syntax (e.g. `[closure@src/lib.rs:2:5: 2:9]`).
                 diag.help("consider using an `Fn`, `FnMut`, or `FnOnce` trait bound");
+            }
+            // Also note how `Fn` traits work just in case!
+            if ret_ty.is_closure() {
                 diag.note(
                     "for more information on `Fn` traits and closure types, see \
                      https://doc.rust-lang.org/book/ch13-01-closures.html",
                 );
-            } else if let Some(i_ty) = suggest_impl_iterator(tcx, ret_ty, ty.span, hir_id, def_id) {
-                diag.span_suggestion(
-                    ty.span,
-                    "replace with an appropriate return type",
-                    format!("impl Iterator<Item = {}>", i_ty),
-                    Applicability::MachineApplicable,
-                );
             }
             diag.emit();
 
-            fn_sig
+            ty::Binder::dummy(fn_sig)
         }
         None => <dyn AstConv<'_>>::ty_of_fn(
             icx,
@@ -1256,47 +1256,94 @@ fn infer_return_ty_for_fn_sig<'tcx>(
     }
 }
 
-fn suggest_impl_iterator<'tcx>(
+fn suggest_impl_trait<'tcx>(
     tcx: TyCtxt<'tcx>,
     ret_ty: Ty<'tcx>,
     span: Span,
     hir_id: hir::HirId,
     def_id: LocalDefId,
-) -> Option<Ty<'tcx>> {
-    let Some(iter_trait) = tcx.get_diagnostic_item(sym::Iterator) else { return None; };
-    let Some(iterator_item) = tcx.get_diagnostic_item(sym::IteratorItem) else { return None; };
-    if !tcx
-        .infer_ctxt()
-        .build()
-        .type_implements_trait(iter_trait, [ret_ty], tcx.param_env(def_id))
-        .must_apply_modulo_regions()
-    {
-        return None;
-    }
-    let infcx = tcx.infer_ctxt().build();
-    let ocx = ObligationCtxt::new_in_snapshot(&infcx);
-    // Find the type of `Iterator::Item`.
-    let origin = TypeVariableOrigin { kind: TypeVariableOriginKind::TypeInference, span };
-    let ty_var = infcx.next_ty_var(origin);
-    let projection = ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::Projection(
-        ty::ProjectionPredicate {
-            projection_ty: tcx.mk_alias_ty(iterator_item, tcx.mk_substs([ret_ty.into()].iter())),
-            term: ty_var.into(),
-        },
-    )));
-    // Add `<ret_ty as Iterator>::Item = _` obligation.
-    ocx.register_obligation(crate::traits::Obligation::misc(
-        tcx,
-        span,
-        hir_id,
-        tcx.param_env(def_id),
-        projection,
-    ));
-    if ocx.select_where_possible().is_empty()
-        && let item_ty = infcx.resolve_vars_if_possible(ty_var)
-        && item_ty.is_suggestable(tcx, false)
-    {
-        return Some(item_ty);
+) -> Option<String> {
+    let format_as_assoc: fn(_, _, _, _, _) -> _ =
+        |tcx: TyCtxt<'tcx>,
+         _: ty::SubstsRef<'tcx>,
+         trait_def_id: DefId,
+         assoc_item_def_id: DefId,
+         item_ty: Ty<'tcx>| {
+            let trait_name = tcx.item_name(trait_def_id);
+            let assoc_name = tcx.item_name(assoc_item_def_id);
+            Some(format!("impl {trait_name}<{assoc_name} = {item_ty}>"))
+        };
+    let format_as_parenthesized: fn(_, _, _, _, _) -> _ =
+        |tcx: TyCtxt<'tcx>,
+         substs: ty::SubstsRef<'tcx>,
+         trait_def_id: DefId,
+         _: DefId,
+         item_ty: Ty<'tcx>| {
+            let trait_name = tcx.item_name(trait_def_id);
+            let args_tuple = substs.type_at(1);
+            let ty::Tuple(types) = *args_tuple.kind() else { return None; };
+            if !types.is_suggestable(tcx, false) {
+                return None;
+            }
+            let maybe_ret =
+                if item_ty.is_unit() { String::new() } else { format!(" -> {item_ty}") };
+            Some(format!(
+                "impl {trait_name}({}){maybe_ret}",
+                types.iter().map(|ty| ty.to_string()).collect::<Vec<_>>().join(", ")
+            ))
+        };
+
+    for (trait_def_id, assoc_item_def_id, formatter) in [
+        (
+            tcx.get_diagnostic_item(sym::Iterator),
+            tcx.get_diagnostic_item(sym::IteratorItem),
+            format_as_assoc,
+        ),
+        (
+            tcx.lang_items().future_trait(),
+            tcx.get_diagnostic_item(sym::FutureOutput),
+            format_as_assoc,
+        ),
+        (tcx.lang_items().fn_trait(), tcx.lang_items().fn_once_output(), format_as_parenthesized),
+        (
+            tcx.lang_items().fn_mut_trait(),
+            tcx.lang_items().fn_once_output(),
+            format_as_parenthesized,
+        ),
+        (
+            tcx.lang_items().fn_once_trait(),
+            tcx.lang_items().fn_once_output(),
+            format_as_parenthesized,
+        ),
+    ] {
+        let Some(trait_def_id) = trait_def_id else { continue; };
+        let Some(assoc_item_def_id) = assoc_item_def_id else { continue; };
+        if tcx.def_kind(assoc_item_def_id) != DefKind::AssocTy {
+            continue;
+        }
+        let param_env = tcx.param_env(def_id);
+        let infcx = tcx.infer_ctxt().build();
+        let substs = ty::InternalSubsts::for_item(tcx, trait_def_id, |param, _| {
+            if param.index == 0 { ret_ty.into() } else { infcx.var_for_def(span, param) }
+        });
+        if !infcx.type_implements_trait(trait_def_id, substs, param_env).must_apply_modulo_regions()
+        {
+            continue;
+        }
+        let ocx = ObligationCtxt::new_in_snapshot(&infcx);
+        let item_ty = ocx.normalize(
+            &ObligationCause::misc(span, hir_id),
+            param_env,
+            tcx.mk_projection(assoc_item_def_id, substs),
+        );
+        // FIXME(compiler-errors): We may benefit from resolving regions here.
+        if ocx.select_where_possible().is_empty()
+            && let item_ty = infcx.resolve_vars_if_possible(item_ty)
+            && item_ty.is_suggestable(tcx, false)
+            && let Some(sugg) = formatter(tcx, infcx.resolve_vars_if_possible(substs), trait_def_id, assoc_item_def_id, item_ty)
+        {
+            return Some(sugg);
+        }
     }
     None
 }
diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index eb3baba999b..9ec71c6b87e 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -3,17 +3,16 @@ use crate::interface::parse_cfgspecs;
 
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::{emitter::HumanReadableErrorType, registry, ColorConfig};
-use rustc_session::config::InstrumentCoverage;
-use rustc_session::config::Strip;
+use rustc_session::config::rustc_optgroups;
 use rustc_session::config::{build_configuration, build_session_options, to_crate_config};
 use rustc_session::config::{
-    rustc_optgroups, ErrorOutputType, ExternLocation, LocationDetail, Options, Passes,
-};
-use rustc_session::config::{
     BranchProtection, Externs, OomStrategy, OutputType, OutputTypes, PAuthKey, PacRet,
     ProcMacroExecutionStrategy, SymbolManglingVersion, WasiExecModel,
 };
 use rustc_session::config::{CFGuard, ExternEntry, LinkerPluginLto, LtoCli, SwitchWithOptPath};
+use rustc_session::config::{DumpMonoStatsFormat, MirSpanview};
+use rustc_session::config::{ErrorOutputType, ExternLocation, LocationDetail, Options, Strip};
+use rustc_session::config::{InstrumentCoverage, Passes};
 use rustc_session::lint::Level;
 use rustc_session::search_paths::SearchPath;
 use rustc_session::utils::{CanonicalizedPath, NativeLib, NativeLibKind};
@@ -647,6 +646,9 @@ fn test_unstable_options_tracking_hash() {
     untracked!(dump_mir_dir, String::from("abc"));
     untracked!(dump_mir_exclude_pass_number, true);
     untracked!(dump_mir_graphviz, true);
+    untracked!(dump_mir_spanview, Some(MirSpanview::Statement));
+    untracked!(dump_mono_stats, SwitchWithOptPath::Enabled(Some("mono-items-dir/".into())));
+    untracked!(dump_mono_stats_format, DumpMonoStatsFormat::Json);
     untracked!(dylib_lto, true);
     untracked!(emit_stack_sizes, true);
     untracked!(future_incompat_test, true);
diff --git a/compiler/rustc_monomorphize/Cargo.toml b/compiler/rustc_monomorphize/Cargo.toml
index 6ee5330b63f..c8af10576b4 100644
--- a/compiler/rustc_monomorphize/Cargo.toml
+++ b/compiler/rustc_monomorphize/Cargo.toml
@@ -6,6 +6,8 @@ edition = "2021"
 [lib]
 
 [dependencies]
+serde = "1"
+serde_json = "1"
 smallvec = { version = "1.8.1", features = [ "union", "may_dangle" ] }
 tracing = "0.1"
 rustc_data_structures = { path = "../rustc_data_structures" }
diff --git a/compiler/rustc_monomorphize/src/partitioning/mod.rs b/compiler/rustc_monomorphize/src/partitioning/mod.rs
index 4f25fc71314..97fbb458e79 100644
--- a/compiler/rustc_monomorphize/src/partitioning/mod.rs
+++ b/compiler/rustc_monomorphize/src/partitioning/mod.rs
@@ -102,14 +102,14 @@ use std::path::{Path, PathBuf};
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::sync;
-use rustc_hir::def_id::DefIdSet;
+use rustc_hir::def_id::{DefIdSet, LOCAL_CRATE};
 use rustc_middle::mir;
 use rustc_middle::mir::mono::MonoItem;
 use rustc_middle::mir::mono::{CodegenUnit, Linkage};
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::TyCtxt;
-use rustc_session::config::SwitchWithOptPath;
+use rustc_session::config::{DumpMonoStatsFormat, SwitchWithOptPath};
 use rustc_span::symbol::Symbol;
 
 use crate::collector::InliningMap;
@@ -417,7 +417,7 @@ fn collect_and_partition_mono_items(tcx: TyCtxt<'_>, (): ()) -> (&DefIdSet, &[Co
     // Output monomorphization stats per def_id
     if let SwitchWithOptPath::Enabled(ref path) = tcx.sess.opts.unstable_opts.dump_mono_stats {
         if let Err(err) =
-            dump_mono_items_stats(tcx, &codegen_units, path, tcx.sess.opts.crate_name.as_deref())
+            dump_mono_items_stats(tcx, &codegen_units, path, tcx.crate_name(LOCAL_CRATE))
         {
             tcx.sess.emit_fatal(CouldntDumpMonoStats { error: err.to_string() });
         }
@@ -483,7 +483,7 @@ fn dump_mono_items_stats<'tcx>(
     tcx: TyCtxt<'tcx>,
     codegen_units: &[CodegenUnit<'tcx>],
     output_directory: &Option<PathBuf>,
-    crate_name: Option<&str>,
+    crate_name: Symbol,
 ) -> Result<(), Box<dyn std::error::Error>> {
     let output_directory = if let Some(ref directory) = output_directory {
         fs::create_dir_all(directory)?;
@@ -492,9 +492,11 @@ fn dump_mono_items_stats<'tcx>(
         Path::new(".")
     };
 
-    let filename = format!("{}.mono_items.md", crate_name.unwrap_or("unknown-crate"));
+    let format = tcx.sess.opts.unstable_opts.dump_mono_stats_format;
+    let ext = format.extension();
+    let filename = format!("{crate_name}.mono_items.{ext}");
     let output_path = output_directory.join(&filename);
-    let file = File::create(output_path)?;
+    let file = File::create(&output_path)?;
     let mut file = BufWriter::new(file);
 
     // Gather instantiated mono items grouped by def_id
@@ -508,30 +510,44 @@ fn dump_mono_items_stats<'tcx>(
         }
     }
 
+    #[derive(serde::Serialize)]
+    struct MonoItem {
+        name: String,
+        instantiation_count: usize,
+        size_estimate: usize,
+        total_estimate: usize,
+    }
+
     // Output stats sorted by total instantiated size, from heaviest to lightest
     let mut stats: Vec<_> = items_per_def_id
         .into_iter()
         .map(|(def_id, items)| {
+            let name = with_no_trimmed_paths!(tcx.def_path_str(def_id));
             let instantiation_count = items.len();
             let size_estimate = items[0].size_estimate(tcx);
             let total_estimate = instantiation_count * size_estimate;
-            (def_id, instantiation_count, size_estimate, total_estimate)
+            MonoItem { name, instantiation_count, size_estimate, total_estimate }
         })
         .collect();
-    stats.sort_unstable_by_key(|(_, _, _, total_estimate)| cmp::Reverse(*total_estimate));
+    stats.sort_unstable_by_key(|item| cmp::Reverse(item.total_estimate));
 
     if !stats.is_empty() {
-        writeln!(
-            file,
-            "| Item | Instantiation count | Estimated Cost Per Instantiation | Total Estimated Cost |"
-        )?;
-        writeln!(file, "| --- | ---: | ---: | ---: |")?;
-        for (def_id, instantiation_count, size_estimate, total_estimate) in stats {
-            let item = with_no_trimmed_paths!(tcx.def_path_str(def_id));
-            writeln!(
-                file,
-                "| {item} | {instantiation_count} | {size_estimate} | {total_estimate} |"
-            )?;
+        match format {
+            DumpMonoStatsFormat::Json => serde_json::to_writer(file, &stats)?,
+            DumpMonoStatsFormat::Markdown => {
+                writeln!(
+                    file,
+                    "| Item | Instantiation count | Estimated Cost Per Instantiation | Total Estimated Cost |"
+                )?;
+                writeln!(file, "| --- | ---: | ---: | ---: |")?;
+
+                for MonoItem { name, instantiation_count, size_estimate, total_estimate } in stats {
+                    writeln!(
+                        file,
+                        "| `{name}` | {instantiation_count} | {size_estimate} | {total_estimate} |"
+                    )?;
+                }
+            }
         }
     }
 
diff --git a/compiler/rustc_query_impl/Cargo.toml b/compiler/rustc_query_impl/Cargo.toml
index b2111a1262a..46e77626479 100644
--- a/compiler/rustc_query_impl/Cargo.toml
+++ b/compiler/rustc_query_impl/Cargo.toml
@@ -4,7 +4,7 @@ version = "0.0.0"
 edition = "2021"
 
 [lib]
-doctest = false
+
 
 [dependencies]
 measureme = "10.0.0"
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index 02e3992a6a9..5f78f6d079d 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -2981,3 +2981,21 @@ pub enum ProcMacroExecutionStrategy {
     /// Run the proc-macro code on a different thread.
     CrossThread,
 }
+
+/// Which format to use for `-Z dump-mono-stats`
+#[derive(Clone, Copy, PartialEq, Hash, Debug)]
+pub enum DumpMonoStatsFormat {
+    /// Pretty-print a markdown table
+    Markdown,
+    /// Emit structured JSON
+    Json,
+}
+
+impl DumpMonoStatsFormat {
+    pub fn extension(self) -> &'static str {
+        match self {
+            Self::Markdown => "md",
+            Self::Json => "json",
+        }
+    }
+}
diff --git a/compiler/rustc_session/src/errors.rs b/compiler/rustc_session/src/errors.rs
index e72b76cfee9..f5a72573d58 100644
--- a/compiler/rustc_session/src/errors.rs
+++ b/compiler/rustc_session/src/errors.rs
@@ -260,9 +260,11 @@ pub(crate) struct InvalidFloatLiteralSuffix {
 
 #[derive(Diagnostic)]
 #[diag(session_int_literal_too_large)]
+#[note]
 pub(crate) struct IntLiteralTooLarge {
     #[primary_span]
     pub span: Span,
+    pub limit: String,
 }
 
 #[derive(Diagnostic)]
@@ -361,8 +363,15 @@ pub fn report_lit_error(sess: &ParseSess, err: LitError, lit: token::Lit, span:
                 _ => unreachable!(),
             };
         }
-        LitError::IntTooLarge => {
-            sess.emit_err(IntLiteralTooLarge { span });
+        LitError::IntTooLarge(base) => {
+            let max = u128::MAX;
+            let limit = match base {
+                2 => format!("{max:#b}"),
+                8 => format!("{max:#o}"),
+                16 => format!("{max:#x}"),
+                _ => format!("{max}"),
+            };
+            sess.emit_err(IntLiteralTooLarge { span, limit });
         }
     }
 }
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index 9bf581ff73d..b379aef80fb 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -377,6 +377,7 @@ mod desc {
     pub const parse_linker_flavor: &str = ::rustc_target::spec::LinkerFlavorCli::one_of();
     pub const parse_optimization_fuel: &str = "crate=integer";
     pub const parse_mir_spanview: &str = "`statement` (default), `terminator`, or `block`";
+    pub const parse_dump_mono_stats: &str = "`markdown` (default) or `json`";
     pub const parse_instrument_coverage: &str =
         "`all` (default), `except-unused-generics`, `except-unused-functions`, or `off`";
     pub const parse_unpretty: &str = "`string` or `string=string`";
@@ -820,6 +821,21 @@ mod parse {
         true
     }
 
+    pub(crate) fn parse_dump_mono_stats(slot: &mut DumpMonoStatsFormat, v: Option<&str>) -> bool {
+        match v {
+            None => true,
+            Some("json") => {
+                *slot = DumpMonoStatsFormat::Json;
+                true
+            }
+            Some("markdown") => {
+                *slot = DumpMonoStatsFormat::Markdown;
+                true
+            }
+            Some(_) => false,
+        }
+    }
+
     pub(crate) fn parse_instrument_coverage(
         slot: &mut Option<InstrumentCoverage>,
         v: Option<&str>,
@@ -1295,7 +1311,9 @@ options! {
         an additional `.html` file showing the computed coverage spans."),
     dump_mono_stats: SwitchWithOptPath = (SwitchWithOptPath::Disabled,
         parse_switch_with_opt_path, [UNTRACKED],
-        "output statistics about monomorphization collection (format: markdown)"),
+        "output statistics about monomorphization collection"),
+    dump_mono_stats_format: DumpMonoStatsFormat = (DumpMonoStatsFormat::Markdown, parse_dump_mono_stats, [UNTRACKED],
+        "the format to use for -Z dump-mono-stats (`markdown` (default) or `json`)"),
     dwarf_version: Option<u32> = (None, parse_opt_number, [TRACKED],
         "version of DWARF debug information to emit (default: 2 or 4, depending on platform)"),
     dylib_lto: bool = (false, parse_bool, [UNTRACKED],
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 85510fa2c66..5d5f8d6d654 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -193,6 +193,7 @@ symbols! {
         FromIterator,
         FromResidual,
         Future,
+        FutureOutput,
         FxHashMap,
         FxHashSet,
         GlobalAlloc,