From fb9cc984d0118c4d8316bca0535be43e45292c78 Mon Sep 17 00:00:00 2001
From: ismailarilik <arilik.ismail@gmail.com>
Date: Thu, 3 Oct 2024 21:59:52 +0300
Subject: [PATCH 01/15] Handle `rustc_resolve` cases of
 `rustc::potential_query_instability` lint

---
 compiler/rustc_middle/src/ty/mod.rs           |  2 +-
 compiler/rustc_resolve/src/diagnostics.rs     |  4 ++--
 compiler/rustc_resolve/src/imports.rs         |  8 +++----
 compiler/rustc_resolve/src/late.rs            | 14 +++++------
 .../rustc_resolve/src/late/diagnostics.rs     |  2 +-
 compiler/rustc_resolve/src/lib.rs             | 23 +++++++++----------
 compiler/rustc_resolve/src/macros.rs          |  4 ++--
 7 files changed, 28 insertions(+), 29 deletions(-)

diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index ed24fcc7eb88a..0c317741a9fd6 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -175,7 +175,7 @@ pub struct ResolverGlobalCtxt {
     /// Item with a given `LocalDefId` was defined during macro expansion with ID `ExpnId`.
     pub expn_that_defined: FxHashMap<LocalDefId, ExpnId>,
     pub effective_visibilities: EffectiveVisibilities,
-    pub extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
+    pub extern_crate_map: FxIndexMap<LocalDefId, CrateNum>,
     pub maybe_unused_trait_imports: FxIndexSet<LocalDefId>,
     pub module_children: LocalDefIdMap<Vec<ModChild>>,
     pub glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index 5437ca65935f8..75bd4d36d3362 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -5,7 +5,7 @@ use rustc_ast::{
     self as ast, CRATE_NODE_ID, Crate, ItemKind, MetaItemInner, MetaItemKind, ModKind, NodeId, Path,
 };
 use rustc_ast_pretty::pprust;
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
 use rustc_errors::codes::*;
 use rustc_errors::{
     Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, MultiSpan, SuggestionStyle,
@@ -2842,7 +2842,7 @@ fn show_candidates(
                 let mut kinds = accessible_path_strings
                     .iter()
                     .map(|(_, descr, _, _, _)| *descr)
-                    .collect::<FxHashSet<&str>>()
+                    .collect::<FxIndexSet<&str>>()
                     .into_iter();
                 let kind = if let Some(kind) = kinds.next()
                     && let None = kinds.next()
diff --git a/compiler/rustc_resolve/src/imports.rs b/compiler/rustc_resolve/src/imports.rs
index 51fbcb8ebb805..f767934e10d4d 100644
--- a/compiler/rustc_resolve/src/imports.rs
+++ b/compiler/rustc_resolve/src/imports.rs
@@ -4,7 +4,7 @@ use std::cell::Cell;
 use std::mem;
 
 use rustc_ast::NodeId;
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
 use rustc_data_structures::intern::Interned;
 use rustc_errors::codes::*;
 use rustc_errors::{Applicability, MultiSpan, pluralize, struct_span_code_err};
@@ -220,7 +220,7 @@ impl<'ra> ImportData<'ra> {
 pub(crate) struct NameResolution<'ra> {
     /// Single imports that may define the name in the namespace.
     /// Imports are arena-allocated, so it's ok to use pointers as keys.
-    pub single_imports: FxHashSet<Import<'ra>>,
+    pub single_imports: FxIndexSet<Import<'ra>>,
     /// The least shadowable known binding for this name, or None if there are no known bindings.
     pub binding: Option<NameBinding<'ra>>,
     pub shadowed_glob: Option<NameBinding<'ra>>,
@@ -482,7 +482,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                 let key = BindingKey::new(target, ns);
                 let _ = this.try_define(import.parent_scope.module, key, dummy_binding, false);
                 this.update_resolution(import.parent_scope.module, key, false, |_, resolution| {
-                    resolution.single_imports.remove(&import);
+                    resolution.single_imports.shift_remove(&import);
                 })
             });
             self.record_use(target, dummy_binding, Used::Other);
@@ -837,7 +837,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                         }
                         let key = BindingKey::new(target, ns);
                         this.update_resolution(parent, key, false, |_, resolution| {
-                            resolution.single_imports.remove(&import);
+                            resolution.single_imports.shift_remove(&import);
                         });
                     }
                 }
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 033cd7d58705d..ec3289017e758 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -15,7 +15,7 @@ use std::mem::{replace, swap, take};
 use rustc_ast::ptr::P;
 use rustc_ast::visit::{AssocCtxt, BoundKind, FnCtxt, FnKind, Visitor, visit_opt, walk_list};
 use rustc_ast::*;
-use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
+use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet};
 use rustc_errors::codes::*;
 use rustc_errors::{Applicability, DiagArgValue, IntoDiagArg, StashKey, Suggestions};
 use rustc_hir::def::Namespace::{self, *};
@@ -44,7 +44,7 @@ mod diagnostics;
 
 type Res = def::Res<NodeId>;
 
-type IdentMap<T> = FxHashMap<Ident, T>;
+type IdentMap<T> = FxIndexMap<Ident, T>;
 
 use diagnostics::{ElisionFnParameter, LifetimeElisionCandidate, MissingLifetime};
 
@@ -640,7 +640,7 @@ struct DiagMetadata<'ast> {
 
     /// A list of labels as of yet unused. Labels will be removed from this map when
     /// they are used (in a `break` or `continue` statement)
-    unused_labels: FxHashMap<NodeId, Span>,
+    unused_labels: FxIndexMap<NodeId, Span>,
 
     /// Only used for better errors on `let x = { foo: bar };`.
     /// In the case of a parse error with `let x = { foo: bar, };`, this isn't needed, it's only
@@ -1550,7 +1550,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                         // Allow all following defaults to refer to this type parameter.
                         forward_ty_ban_rib
                             .bindings
-                            .remove(&Ident::with_dummy_span(param.ident.name));
+                            .shift_remove(&Ident::with_dummy_span(param.ident.name));
                     }
                     GenericParamKind::Const { ref ty, kw_span: _, ref default } => {
                         // Const parameters can't have param bounds.
@@ -1578,7 +1578,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                         // Allow all following defaults to refer to this const parameter.
                         forward_const_ban_rib
                             .bindings
-                            .remove(&Ident::with_dummy_span(param.ident.name));
+                            .shift_remove(&Ident::with_dummy_span(param.ident.name));
                     }
                 }
             }
@@ -2236,7 +2236,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
             let local_candidates = self.lifetime_elision_candidates.take();
 
             if let Some(candidates) = local_candidates {
-                let distinct: FxHashSet<_> = candidates.iter().map(|(res, _)| *res).collect();
+                let distinct: FxIndexSet<_> = candidates.iter().map(|(res, _)| *res).collect();
                 let lifetime_count = distinct.len();
                 if lifetime_count != 0 {
                     parameter_info.push(ElisionFnParameter {
@@ -4621,7 +4621,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                     Ok((node_id, _)) => {
                         // Since this res is a label, it is never read.
                         self.r.label_res_map.insert(expr.id, node_id);
-                        self.diag_metadata.unused_labels.remove(&node_id);
+                        self.diag_metadata.unused_labels.shift_remove(&node_id);
                     }
                     Err(error) => {
                         self.report_error(label.ident.span, error);
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index f0632a21091bb..af0fecb59329b 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -960,7 +960,7 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
                                     Applicability::MaybeIncorrect,
                                 );
                                 // Do not lint against unused label when we suggest them.
-                                self.diag_metadata.unused_labels.remove(node_id);
+                                self.diag_metadata.unused_labels.shift_remove(node_id);
                             }
                         }
                     }
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index 35d491cfc18e7..e913b196ca0f9 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -9,7 +9,6 @@
 // tidy-alphabetical-start
 #![allow(internal_features)]
 #![allow(rustc::diagnostic_outside_of_impl)]
-#![allow(rustc::potential_query_instability)]
 #![allow(rustc::untranslatable_diagnostic)]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]
@@ -1022,7 +1021,7 @@ pub struct Resolver<'ra, 'tcx> {
     graph_root: Module<'ra>,
 
     prelude: Option<Module<'ra>>,
-    extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'ra>>,
+    extern_prelude: FxIndexMap<Ident, ExternPreludeEntry<'ra>>,
 
     /// N.B., this is used only for better diagnostics, not name resolution itself.
     field_names: LocalDefIdMap<Vec<Ident>>,
@@ -1055,7 +1054,7 @@ pub struct Resolver<'ra, 'tcx> {
     extra_lifetime_params_map: NodeMap<Vec<(Ident, NodeId, LifetimeRes)>>,
 
     /// `CrateNum` resolutions of `extern crate` items.
-    extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
+    extern_crate_map: FxIndexMap<LocalDefId, CrateNum>,
     module_children: LocalDefIdMap<Vec<ModChild>>,
     trait_map: NodeMap<Vec<TraitCandidate>>,
 
@@ -1078,7 +1077,7 @@ pub struct Resolver<'ra, 'tcx> {
     /// some AST passes can generate identifiers that only resolve to local or
     /// lang items.
     empty_module: Module<'ra>,
-    module_map: FxHashMap<DefId, Module<'ra>>,
+    module_map: FxIndexMap<DefId, Module<'ra>>,
     binding_parent_modules: FxHashMap<NameBinding<'ra>, Module<'ra>>,
 
     underscore_disambiguator: u32,
@@ -1114,16 +1113,16 @@ pub struct Resolver<'ra, 'tcx> {
     macro_names: FxHashSet<Ident>,
     builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
     registered_tools: &'tcx RegisteredTools,
-    macro_use_prelude: FxHashMap<Symbol, NameBinding<'ra>>,
+    macro_use_prelude: FxIndexMap<Symbol, NameBinding<'ra>>,
     macro_map: FxHashMap<DefId, MacroData>,
     dummy_ext_bang: Lrc<SyntaxExtension>,
     dummy_ext_derive: Lrc<SyntaxExtension>,
     non_macro_attr: MacroData,
     local_macro_def_scopes: FxHashMap<LocalDefId, Module<'ra>>,
     ast_transform_scopes: FxHashMap<LocalExpnId, Module<'ra>>,
-    unused_macros: FxHashMap<LocalDefId, (NodeId, Ident)>,
+    unused_macros: FxIndexMap<LocalDefId, (NodeId, Ident)>,
     /// A map from the macro to all its potentially unused arms.
-    unused_macro_rules: FxIndexMap<LocalDefId, FxHashMap<usize, (Ident, Span)>>,
+    unused_macro_rules: FxIndexMap<LocalDefId, FxIndexMap<usize, (Ident, Span)>>,
     proc_macro_stubs: FxHashSet<LocalDefId>,
     /// Traces collected during macro resolution and validated when it's complete.
     single_segment_macro_resolutions:
@@ -1235,7 +1234,7 @@ impl<'ra> ResolverArenas<'ra> {
         expn_id: ExpnId,
         span: Span,
         no_implicit_prelude: bool,
-        module_map: &mut FxHashMap<DefId, Module<'ra>>,
+        module_map: &mut FxIndexMap<DefId, Module<'ra>>,
         module_self_bindings: &mut FxHashMap<Module<'ra>, NameBinding<'ra>>,
     ) -> Module<'ra> {
         let module = Module(Interned::new_unchecked(self.modules.alloc(ModuleData::new(
@@ -1380,7 +1379,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         arenas: &'ra ResolverArenas<'ra>,
     ) -> Resolver<'ra, 'tcx> {
         let root_def_id = CRATE_DEF_ID.to_def_id();
-        let mut module_map = FxHashMap::default();
+        let mut module_map = FxIndexMap::default();
         let mut module_self_bindings = FxHashMap::default();
         let graph_root = arenas.new_module(
             None,
@@ -1397,7 +1396,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             ExpnId::root(),
             DUMMY_SP,
             true,
-            &mut FxHashMap::default(),
+            &mut FxIndexMap::default(),
             &mut FxHashMap::default(),
         );
 
@@ -1413,7 +1412,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         let mut invocation_parents = FxHashMap::default();
         invocation_parents.insert(LocalExpnId::ROOT, InvocationParent::ROOT);
 
-        let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = tcx
+        let mut extern_prelude: FxIndexMap<Ident, ExternPreludeEntry<'_>> = tcx
             .sess
             .opts
             .externs
@@ -1513,7 +1512,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             macro_names: FxHashSet::default(),
             builtin_macros: Default::default(),
             registered_tools,
-            macro_use_prelude: FxHashMap::default(),
+            macro_use_prelude: FxIndexMap::default(),
             macro_map: FxHashMap::default(),
             dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(edition)),
             dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(edition)),
diff --git a/compiler/rustc_resolve/src/macros.rs b/compiler/rustc_resolve/src/macros.rs
index a9ebffea8a10b..bb99565f0274e 100644
--- a/compiler/rustc_resolve/src/macros.rs
+++ b/compiler/rustc_resolve/src/macros.rs
@@ -341,7 +341,7 @@ impl<'ra, 'tcx> ResolverExpand for Resolver<'ra, 'tcx> {
     fn record_macro_rule_usage(&mut self, id: NodeId, rule_i: usize) {
         let did = self.local_def_id(id);
         if let Some(rules) = self.unused_macro_rules.get_mut(&did) {
-            rules.remove(&rule_i);
+            rules.shift_remove(&rule_i);
         }
     }
 
@@ -602,7 +602,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         match res {
             Res::Def(DefKind::Macro(_), def_id) => {
                 if let Some(def_id) = def_id.as_local() {
-                    self.unused_macros.remove(&def_id);
+                    self.unused_macros.shift_remove(&def_id);
                     if self.proc_macro_stubs.contains(&def_id) {
                         self.dcx().emit_err(errors::ProcMacroSameCrate {
                             span: path.span,

From da177090151461fa8151eff966c5817697ab0027 Mon Sep 17 00:00:00 2001
From: ismailarilik <arilik.ismail@gmail.com>
Date: Fri, 25 Oct 2024 09:41:30 +0300
Subject: [PATCH 02/15] Add requested changes by reviewer

---
 compiler/rustc_middle/src/ty/mod.rs           |  2 +-
 compiler/rustc_resolve/src/diagnostics.rs     | 21 ++++++++++++++---
 compiler/rustc_resolve/src/late.rs            | 23 +++++++++++--------
 .../rustc_resolve/src/late/diagnostics.rs     |  6 ++++-
 compiler/rustc_resolve/src/lib.rs             | 20 ++++++++--------
 compiler/rustc_resolve/src/macros.rs          |  8 +++++--
 6 files changed, 54 insertions(+), 26 deletions(-)

diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 0c317741a9fd6..ed24fcc7eb88a 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -175,7 +175,7 @@ pub struct ResolverGlobalCtxt {
     /// Item with a given `LocalDefId` was defined during macro expansion with ID `ExpnId`.
     pub expn_that_defined: FxHashMap<LocalDefId, ExpnId>,
     pub effective_visibilities: EffectiveVisibilities,
-    pub extern_crate_map: FxIndexMap<LocalDefId, CrateNum>,
+    pub extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
     pub maybe_unused_trait_imports: FxIndexSet<LocalDefId>,
     pub module_children: LocalDefIdMap<Vec<ModChild>>,
     pub glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index 75bd4d36d3362..dafb944a6db85 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -5,7 +5,7 @@ use rustc_ast::{
     self as ast, CRATE_NODE_ID, Crate, ItemKind, MetaItemInner, MetaItemKind, ModKind, NodeId, Path,
 };
 use rustc_ast_pretty::pprust;
-use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
+use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::codes::*;
 use rustc_errors::{
     Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, MultiSpan, SuggestionStyle,
@@ -1086,6 +1086,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     this.add_module_candidates(module, &mut suggestions, filter_fn, None);
                 }
                 Scope::MacroUsePrelude => {
+                    // The suggestions are deterministically sorted later
+                    #[allow(rustc::potential_query_instability)]
                     suggestions.extend(this.macro_use_prelude.iter().filter_map(
                         |(name, binding)| {
                             let res = binding.res();
@@ -1104,6 +1106,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     }
                 }
                 Scope::ExternPrelude => {
+                    // The suggestions are deterministically sorted later
+                    #[allow(rustc::potential_query_instability)]
                     suggestions.extend(this.extern_prelude.iter().filter_map(|(ident, _)| {
                         let res = Res::Def(DefKind::Mod, CRATE_DEF_ID.to_def_id());
                         filter_fn(res).then_some(TypoSuggestion::typo_from_ident(*ident, res))
@@ -1362,6 +1366,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         );
 
         if lookup_ident.span.at_least_rust_2018() {
+            // It will be sorted later.
+            #[allow(rustc::potential_query_instability)]
             for ident in self.extern_prelude.clone().into_keys() {
                 if ident.span.from_expansion() {
                     // Idents are adjusted to the root context before being
@@ -1467,7 +1473,11 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             return;
         }
 
-        let unused_macro = self.unused_macros.iter().find_map(|(def_id, (_, unused_ident))| {
+        // Make ordering consistent before iteration
+        #[allow(rustc::potential_query_instability)]
+        let mut unused_macros: Vec<_> = self.unused_macros.iter().collect();
+        unused_macros.sort_by_key(|&(_, (key, _))| key);
+        let unused_macro = unused_macros.iter().find_map(|(def_id, (_, unused_ident))| {
             if unused_ident.name == ident.name { Some((def_id, unused_ident)) } else { None }
         });
 
@@ -1954,6 +1964,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         ident: Symbol,
         current_module: Module<'ra>,
     ) -> Option<Symbol> {
+        // It will be sorted later.
+        #[allow(rustc::potential_query_instability)]
         let mut candidates = self
             .extern_prelude
             .keys()
@@ -2342,6 +2354,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         // Sort extern crate names in *reverse* order to get
         // 1) some consistent ordering for emitted diagnostics, and
         // 2) `std` suggestions before `core` suggestions.
+        #[allow(rustc::potential_query_instability)]
         let mut extern_crate_names =
             self.extern_prelude.keys().map(|ident| ident.name).collect::<Vec<_>>();
         extern_crate_names.sort_by(|a, b| b.as_str().partial_cmp(a.as_str()).unwrap());
@@ -2839,10 +2852,12 @@ fn show_candidates(
             } else {
                 // Get the unique item kinds and if there's only one, we use the right kind name
                 // instead of the more generic "items".
+                // Ordering is not important here.
+                #[allow(rustc::potential_query_instability)]
                 let mut kinds = accessible_path_strings
                     .iter()
                     .map(|(_, descr, _, _, _)| *descr)
-                    .collect::<FxIndexSet<&str>>()
+                    .collect::<FxHashSet<&str>>()
                     .into_iter();
                 let kind = if let Some(kind) = kinds.next()
                     && let None = kinds.next()
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index ec3289017e758..606b3695903a4 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -15,7 +15,7 @@ use std::mem::{replace, swap, take};
 use rustc_ast::ptr::P;
 use rustc_ast::visit::{AssocCtxt, BoundKind, FnCtxt, FnKind, Visitor, visit_opt, walk_list};
 use rustc_ast::*;
-use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet};
+use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
 use rustc_errors::codes::*;
 use rustc_errors::{Applicability, DiagArgValue, IntoDiagArg, StashKey, Suggestions};
 use rustc_hir::def::Namespace::{self, *};
@@ -44,8 +44,6 @@ mod diagnostics;
 
 type Res = def::Res<NodeId>;
 
-type IdentMap<T> = FxIndexMap<Ident, T>;
-
 use diagnostics::{ElisionFnParameter, LifetimeElisionCandidate, MissingLifetime};
 
 #[derive(Copy, Clone, Debug)]
@@ -261,7 +259,7 @@ impl RibKind<'_> {
 /// resolving, the name is looked up from inside out.
 #[derive(Debug)]
 pub(crate) struct Rib<'ra, R = Res> {
-    pub bindings: IdentMap<R>,
+    pub bindings: FxIndexMap<Ident, R>,
     pub kind: RibKind<'ra>,
 }
 
@@ -640,7 +638,7 @@ struct DiagMetadata<'ast> {
 
     /// A list of labels as of yet unused. Labels will be removed from this map when
     /// they are used (in a `break` or `continue` statement)
-    unused_labels: FxIndexMap<NodeId, Span>,
+    unused_labels: FxHashMap<NodeId, Span>,
 
     /// Only used for better errors on `let x = { foo: bar };`.
     /// In the case of a parse error with `let x = { foo: bar, };`, this isn't needed, it's only
@@ -2236,7 +2234,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
             let local_candidates = self.lifetime_elision_candidates.take();
 
             if let Some(candidates) = local_candidates {
-                let distinct: FxIndexSet<_> = candidates.iter().map(|(res, _)| *res).collect();
+                let distinct: FxHashSet<_> = candidates.iter().map(|(res, _)| *res).collect();
                 let lifetime_count = distinct.len();
                 if lifetime_count != 0 {
                     parameter_info.push(ElisionFnParameter {
@@ -2260,6 +2258,8 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                         }
                     }));
                 }
+                // Ordering is not important here.
+                #[allow(rustc::potential_query_instability)]
                 let mut distinct_iter = distinct.into_iter();
                 if let Some(res) = distinct_iter.next() {
                     match elision_lifetime {
@@ -3868,7 +3868,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
         }
     }
 
-    fn innermost_rib_bindings(&mut self, ns: Namespace) -> &mut IdentMap<Res> {
+    fn innermost_rib_bindings(&mut self, ns: Namespace) -> &mut FxIndexMap<Ident, Res> {
         &mut self.ribs[ns].last_mut().unwrap().bindings
     }
 
@@ -4621,7 +4621,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                     Ok((node_id, _)) => {
                         // Since this res is a label, it is never read.
                         self.r.label_res_map.insert(expr.id, node_id);
-                        self.diag_metadata.unused_labels.shift_remove(&node_id);
+                        self.diag_metadata.unused_labels.remove(&node_id);
                     }
                     Err(error) => {
                         self.report_error(label.ident.span, error);
@@ -5046,7 +5046,12 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         let mut late_resolution_visitor = LateResolutionVisitor::new(self);
         late_resolution_visitor.resolve_doc_links(&krate.attrs, MaybeExported::Ok(CRATE_NODE_ID));
         visit::walk_crate(&mut late_resolution_visitor, krate);
-        for (id, span) in late_resolution_visitor.diag_metadata.unused_labels.iter() {
+        // Make ordering consistent before iteration
+        #[allow(rustc::potential_query_instability)]
+        let mut unused_labels: Vec<_> =
+            late_resolution_visitor.diag_metadata.unused_labels.iter().collect();
+        unused_labels.sort_by_key(|&(key, _)| key);
+        for (id, span) in unused_labels {
             self.lint_buffer.buffer_lint(
                 lint::builtin::UNUSED_LABELS,
                 *id,
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index af0fecb59329b..4ebc2afd68d23 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -960,7 +960,7 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
                                     Applicability::MaybeIncorrect,
                                 );
                                 // Do not lint against unused label when we suggest them.
-                                self.diag_metadata.unused_labels.shift_remove(node_id);
+                                self.diag_metadata.unused_labels.remove(node_id);
                             }
                         }
                     }
@@ -1928,6 +1928,8 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
         let Some(default_trait) = default_trait else {
             return;
         };
+        // The ordering is not important here.
+        #[allow(rustc::potential_query_instability)]
         if self
             .r
             .extern_crate_map
@@ -2166,6 +2168,8 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
                         // Items from the prelude
                         if !module.no_implicit_prelude {
                             let extern_prelude = self.r.extern_prelude.clone();
+                            // It is sorted later so ordering is not important.
+                            #[allow(rustc::potential_query_instability)]
                             names.extend(extern_prelude.iter().flat_map(|(ident, _)| {
                                 self.r
                                     .crate_loader(|c| c.maybe_process_path_extern(ident.name))
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index e913b196ca0f9..7d06c0b692047 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -1021,7 +1021,7 @@ pub struct Resolver<'ra, 'tcx> {
     graph_root: Module<'ra>,
 
     prelude: Option<Module<'ra>>,
-    extern_prelude: FxIndexMap<Ident, ExternPreludeEntry<'ra>>,
+    extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'ra>>,
 
     /// N.B., this is used only for better diagnostics, not name resolution itself.
     field_names: LocalDefIdMap<Vec<Ident>>,
@@ -1054,7 +1054,7 @@ pub struct Resolver<'ra, 'tcx> {
     extra_lifetime_params_map: NodeMap<Vec<(Ident, NodeId, LifetimeRes)>>,
 
     /// `CrateNum` resolutions of `extern crate` items.
-    extern_crate_map: FxIndexMap<LocalDefId, CrateNum>,
+    extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
     module_children: LocalDefIdMap<Vec<ModChild>>,
     trait_map: NodeMap<Vec<TraitCandidate>>,
 
@@ -1077,7 +1077,7 @@ pub struct Resolver<'ra, 'tcx> {
     /// some AST passes can generate identifiers that only resolve to local or
     /// lang items.
     empty_module: Module<'ra>,
-    module_map: FxIndexMap<DefId, Module<'ra>>,
+    module_map: FxHashMap<DefId, Module<'ra>>,
     binding_parent_modules: FxHashMap<NameBinding<'ra>, Module<'ra>>,
 
     underscore_disambiguator: u32,
@@ -1113,14 +1113,14 @@ pub struct Resolver<'ra, 'tcx> {
     macro_names: FxHashSet<Ident>,
     builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
     registered_tools: &'tcx RegisteredTools,
-    macro_use_prelude: FxIndexMap<Symbol, NameBinding<'ra>>,
+    macro_use_prelude: FxHashMap<Symbol, NameBinding<'ra>>,
     macro_map: FxHashMap<DefId, MacroData>,
     dummy_ext_bang: Lrc<SyntaxExtension>,
     dummy_ext_derive: Lrc<SyntaxExtension>,
     non_macro_attr: MacroData,
     local_macro_def_scopes: FxHashMap<LocalDefId, Module<'ra>>,
     ast_transform_scopes: FxHashMap<LocalExpnId, Module<'ra>>,
-    unused_macros: FxIndexMap<LocalDefId, (NodeId, Ident)>,
+    unused_macros: FxHashMap<LocalDefId, (NodeId, Ident)>,
     /// A map from the macro to all its potentially unused arms.
     unused_macro_rules: FxIndexMap<LocalDefId, FxIndexMap<usize, (Ident, Span)>>,
     proc_macro_stubs: FxHashSet<LocalDefId>,
@@ -1234,7 +1234,7 @@ impl<'ra> ResolverArenas<'ra> {
         expn_id: ExpnId,
         span: Span,
         no_implicit_prelude: bool,
-        module_map: &mut FxIndexMap<DefId, Module<'ra>>,
+        module_map: &mut FxHashMap<DefId, Module<'ra>>,
         module_self_bindings: &mut FxHashMap<Module<'ra>, NameBinding<'ra>>,
     ) -> Module<'ra> {
         let module = Module(Interned::new_unchecked(self.modules.alloc(ModuleData::new(
@@ -1379,7 +1379,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         arenas: &'ra ResolverArenas<'ra>,
     ) -> Resolver<'ra, 'tcx> {
         let root_def_id = CRATE_DEF_ID.to_def_id();
-        let mut module_map = FxIndexMap::default();
+        let mut module_map = FxHashMap::default();
         let mut module_self_bindings = FxHashMap::default();
         let graph_root = arenas.new_module(
             None,
@@ -1396,7 +1396,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             ExpnId::root(),
             DUMMY_SP,
             true,
-            &mut FxIndexMap::default(),
+            &mut FxHashMap::default(),
             &mut FxHashMap::default(),
         );
 
@@ -1412,7 +1412,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         let mut invocation_parents = FxHashMap::default();
         invocation_parents.insert(LocalExpnId::ROOT, InvocationParent::ROOT);
 
-        let mut extern_prelude: FxIndexMap<Ident, ExternPreludeEntry<'_>> = tcx
+        let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = tcx
             .sess
             .opts
             .externs
@@ -1512,7 +1512,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             macro_names: FxHashSet::default(),
             builtin_macros: Default::default(),
             registered_tools,
-            macro_use_prelude: FxIndexMap::default(),
+            macro_use_prelude: FxHashMap::default(),
             macro_map: FxHashMap::default(),
             dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(edition)),
             dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(edition)),
diff --git a/compiler/rustc_resolve/src/macros.rs b/compiler/rustc_resolve/src/macros.rs
index bb99565f0274e..4ff70ce39a999 100644
--- a/compiler/rustc_resolve/src/macros.rs
+++ b/compiler/rustc_resolve/src/macros.rs
@@ -346,7 +346,11 @@ impl<'ra, 'tcx> ResolverExpand for Resolver<'ra, 'tcx> {
     }
 
     fn check_unused_macros(&mut self) {
-        for (_, &(node_id, ident)) in self.unused_macros.iter() {
+        // Make ordering consistent before iteration
+        #[allow(rustc::potential_query_instability)]
+        let mut unused_macros: Vec<_> = self.unused_macros.iter().collect();
+        unused_macros.sort_by_key(|&(_, (key, _))| key);
+        for (_, &(node_id, ident)) in unused_macros {
             self.lint_buffer.buffer_lint(
                 UNUSED_MACROS,
                 node_id,
@@ -602,7 +606,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         match res {
             Res::Def(DefKind::Macro(_), def_id) => {
                 if let Some(def_id) = def_id.as_local() {
-                    self.unused_macros.shift_remove(&def_id);
+                    self.unused_macros.remove(&def_id);
                     if self.proc_macro_stubs.contains(&def_id) {
                         self.dcx().emit_err(errors::ProcMacroSameCrate {
                             span: path.span,

From 34c78ce9e2919a96323d383ef6326b7b3db4a8c9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C4=B0smail=20Ar=C4=B1l=C4=B1k?= <arilik.ismail@gmail.com>
Date: Sun, 27 Oct 2024 09:56:25 +0300
Subject: [PATCH 03/15] Specify sort location in a comment

Co-authored-by: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
---
 compiler/rustc_resolve/src/diagnostics.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index dafb944a6db85..0846d04479ed4 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -1964,7 +1964,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         ident: Symbol,
         current_module: Module<'ra>,
     ) -> Option<Symbol> {
-        // It will be sorted later.
+        // The candidates are sorted just below.
         #[allow(rustc::potential_query_instability)]
         let mut candidates = self
             .extern_prelude

From aeac8a89a655b6e5f459f087e5b51b8dd2a156e0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C4=B0smail=20Ar=C4=B1l=C4=B1k?= <arilik.ismail@gmail.com>
Date: Sun, 27 Oct 2024 09:56:51 +0300
Subject: [PATCH 04/15] Specify sort location in a comment

Co-authored-by: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
---
 compiler/rustc_resolve/src/diagnostics.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index 0846d04479ed4..328013bf93db7 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -1086,7 +1086,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     this.add_module_candidates(module, &mut suggestions, filter_fn, None);
                 }
                 Scope::MacroUsePrelude => {
-                    // The suggestions are deterministically sorted later
+                    // The suggestions are deterministically sorted at the bottom of this function.
                     #[allow(rustc::potential_query_instability)]
                     suggestions.extend(this.macro_use_prelude.iter().filter_map(
                         |(name, binding)| {

From 64d3961adf1bdf35701c31f673ea933b66203a56 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C4=B0smail=20Ar=C4=B1l=C4=B1k?= <arilik.ismail@gmail.com>
Date: Sun, 27 Oct 2024 09:57:06 +0300
Subject: [PATCH 05/15] Specify sort location in a comment

Co-authored-by: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
---
 compiler/rustc_resolve/src/diagnostics.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index 328013bf93db7..37095a543060b 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -1106,7 +1106,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     }
                 }
                 Scope::ExternPrelude => {
-                    // The suggestions are deterministically sorted later
+                    // The suggestions are deterministically sorted at the bottom of this function.
                     #[allow(rustc::potential_query_instability)]
                     suggestions.extend(this.extern_prelude.iter().filter_map(|(ident, _)| {
                         let res = Res::Def(DefKind::Mod, CRATE_DEF_ID.to_def_id());

From 1121d656335648753071b89377b1c2fb4472ec4c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C4=B0smail=20Ar=C4=B1l=C4=B1k?= <arilik.ismail@gmail.com>
Date: Sun, 27 Oct 2024 09:58:02 +0300
Subject: [PATCH 06/15] Clarify reasoning behind allowing this lint in a
 comment

Co-authored-by: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
---
 compiler/rustc_resolve/src/diagnostics.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index 37095a543060b..1463f83ad1fe4 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -2852,7 +2852,7 @@ fn show_candidates(
             } else {
                 // Get the unique item kinds and if there's only one, we use the right kind name
                 // instead of the more generic "items".
-                // Ordering is not important here.
+                // Ordering is not important if there's only one element in the set.
                 #[allow(rustc::potential_query_instability)]
                 let mut kinds = accessible_path_strings
                     .iter()

From 9652373d348e300eae68b112118117f5b92f7151 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C4=B0smail=20Ar=C4=B1l=C4=B1k?= <arilik.ismail@gmail.com>
Date: Sun, 27 Oct 2024 09:58:25 +0300
Subject: [PATCH 07/15] Clarify reasoning behind allowing this lint in a
 comment

Co-authored-by: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
---
 compiler/rustc_resolve/src/late.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 606b3695903a4..e21f7be9a09ef 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -2258,7 +2258,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                         }
                     }));
                 }
-                // Ordering is not important here.
+                // Ordering is not important if there's only one element in the set.
                 #[allow(rustc::potential_query_instability)]
                 let mut distinct_iter = distinct.into_iter();
                 if let Some(res) = distinct_iter.next() {

From e592d7336c6b7c379627d271b12e4c51b2a0522d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C4=B0smail=20Ar=C4=B1l=C4=B1k?= <arilik.ismail@gmail.com>
Date: Sun, 27 Oct 2024 10:03:15 +0300
Subject: [PATCH 08/15] Clarify reasoning behind allowing this lint in a
 comment

Co-authored-by: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
---
 compiler/rustc_resolve/src/late/diagnostics.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index 4ebc2afd68d23..541afea13291c 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -1928,7 +1928,7 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
         let Some(default_trait) = default_trait else {
             return;
         };
-        // The ordering is not important here.
+        // The ordering is not important because `any` is used on the iterator.
         #[allow(rustc::potential_query_instability)]
         if self
             .r

From 477de93119080d2b5bf0305abb545d7d965bb386 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C4=B0smail=20Ar=C4=B1l=C4=B1k?= <arilik.ismail@gmail.com>
Date: Sun, 27 Oct 2024 10:03:57 +0300
Subject: [PATCH 09/15] Specify sort location in a comment

Co-authored-by: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
---
 compiler/rustc_resolve/src/late/diagnostics.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index 541afea13291c..3f830661ba523 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -2168,7 +2168,7 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
                         // Items from the prelude
                         if !module.no_implicit_prelude {
                             let extern_prelude = self.r.extern_prelude.clone();
-                            // It is sorted later so ordering is not important.
+                            // The names are sorted at the bottom of this function.
                             #[allow(rustc::potential_query_instability)]
                             names.extend(extern_prelude.iter().flat_map(|(ident, _)| {
                                 self.r

From 93ab85f3ad250661d6e6d0107a0b7d44c75f9392 Mon Sep 17 00:00:00 2001
From: ismailarilik <arilik.ismail@gmail.com>
Date: Mon, 28 Oct 2024 09:30:45 +0300
Subject: [PATCH 10/15] Sort suggestions in diagnostics to make error reporting
 deterministic

---
 compiler/rustc_resolve/src/diagnostics.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index 1463f83ad1fe4..b6417b654f206 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -1366,7 +1366,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         );
 
         if lookup_ident.span.at_least_rust_2018() {
-            // It will be sorted later.
+            // Extended suggestions will be sorted at the end of this function.
             #[allow(rustc::potential_query_instability)]
             for ident in self.extern_prelude.clone().into_keys() {
                 if ident.span.from_expansion() {
@@ -1422,6 +1422,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             }
         }
 
+        // Make sure error reporting is deterministic.
+        suggestions.sort_by_key(|suggestion| suggestion.did.unwrap().index);
         suggestions
     }
 

From 5d14c349afd52809b0dc35815cc53992c0b3fef3 Mon Sep 17 00:00:00 2001
From: ismailarilik <arilik.ismail@gmail.com>
Date: Mon, 28 Oct 2024 09:45:13 +0300
Subject: [PATCH 11/15] Revert unused_arms to HashMap; they are already sorted
 so no need to use IndexMap for it

---
 compiler/rustc_resolve/src/lib.rs    | 2 +-
 compiler/rustc_resolve/src/macros.rs | 4 +++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index 7d06c0b692047..f1d5f3e2ffa18 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -1122,7 +1122,7 @@ pub struct Resolver<'ra, 'tcx> {
     ast_transform_scopes: FxHashMap<LocalExpnId, Module<'ra>>,
     unused_macros: FxHashMap<LocalDefId, (NodeId, Ident)>,
     /// A map from the macro to all its potentially unused arms.
-    unused_macro_rules: FxIndexMap<LocalDefId, FxIndexMap<usize, (Ident, Span)>>,
+    unused_macro_rules: FxIndexMap<LocalDefId, FxHashMap<usize, (Ident, Span)>>,
     proc_macro_stubs: FxHashSet<LocalDefId>,
     /// Traces collected during macro resolution and validated when it's complete.
     single_segment_macro_resolutions:
diff --git a/compiler/rustc_resolve/src/macros.rs b/compiler/rustc_resolve/src/macros.rs
index 4ff70ce39a999..6305c0094b481 100644
--- a/compiler/rustc_resolve/src/macros.rs
+++ b/compiler/rustc_resolve/src/macros.rs
@@ -341,7 +341,7 @@ impl<'ra, 'tcx> ResolverExpand for Resolver<'ra, 'tcx> {
     fn record_macro_rule_usage(&mut self, id: NodeId, rule_i: usize) {
         let did = self.local_def_id(id);
         if let Some(rules) = self.unused_macro_rules.get_mut(&did) {
-            rules.shift_remove(&rule_i);
+            rules.remove(&rule_i);
         }
     }
 
@@ -360,6 +360,8 @@ impl<'ra, 'tcx> ResolverExpand for Resolver<'ra, 'tcx> {
         }
 
         for (&def_id, unused_arms) in self.unused_macro_rules.iter() {
+            // It is already sorted below.
+            #[allow(rustc::potential_query_instability)]
             let mut unused_arms = unused_arms.iter().collect::<Vec<_>>();
             unused_arms.sort_by_key(|&(&arm_i, _)| arm_i);
 

From f09b6a80351551e04ba5d9dc7da9e3d7245fe725 Mon Sep 17 00:00:00 2001
From: ismailarilik <arilik.ismail@gmail.com>
Date: Sun, 3 Nov 2024 13:33:12 +0300
Subject: [PATCH 12/15] Try to sort `single_imports` before usage to have a
 stable result

The `FxIndexSet` solution seems costly.
---
 compiler/rustc_resolve/src/ident.rs   | 7 ++++++-
 compiler/rustc_resolve/src/imports.rs | 8 ++++----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/compiler/rustc_resolve/src/ident.rs b/compiler/rustc_resolve/src/ident.rs
index b80e0e196ca08..0c06cc2e6a1db 100644
--- a/compiler/rustc_resolve/src/ident.rs
+++ b/compiler/rustc_resolve/src/ident.rs
@@ -984,9 +984,14 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
 
         // --- From now on we either have a glob resolution or no resolution. ---
 
+        // It is sorted before usage so ordering is not important.
+        #[allow(rustc::potential_query_instability)]
+        let mut single_imports: Vec<_> = resolution.single_imports.clone().into_iter().collect();
+        single_imports.sort_by_key(|import| import.0.id());
+
         // Check if one of single imports can still define the name,
         // if it can then our result is not determined and can be invalidated.
-        for single_import in &resolution.single_imports {
+        for single_import in &single_imports {
             if ignore_import == Some(*single_import) {
                 // This branch handles a cycle in single imports.
                 //
diff --git a/compiler/rustc_resolve/src/imports.rs b/compiler/rustc_resolve/src/imports.rs
index f767934e10d4d..51fbcb8ebb805 100644
--- a/compiler/rustc_resolve/src/imports.rs
+++ b/compiler/rustc_resolve/src/imports.rs
@@ -4,7 +4,7 @@ use std::cell::Cell;
 use std::mem;
 
 use rustc_ast::NodeId;
-use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
+use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::intern::Interned;
 use rustc_errors::codes::*;
 use rustc_errors::{Applicability, MultiSpan, pluralize, struct_span_code_err};
@@ -220,7 +220,7 @@ impl<'ra> ImportData<'ra> {
 pub(crate) struct NameResolution<'ra> {
     /// Single imports that may define the name in the namespace.
     /// Imports are arena-allocated, so it's ok to use pointers as keys.
-    pub single_imports: FxIndexSet<Import<'ra>>,
+    pub single_imports: FxHashSet<Import<'ra>>,
     /// The least shadowable known binding for this name, or None if there are no known bindings.
     pub binding: Option<NameBinding<'ra>>,
     pub shadowed_glob: Option<NameBinding<'ra>>,
@@ -482,7 +482,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                 let key = BindingKey::new(target, ns);
                 let _ = this.try_define(import.parent_scope.module, key, dummy_binding, false);
                 this.update_resolution(import.parent_scope.module, key, false, |_, resolution| {
-                    resolution.single_imports.shift_remove(&import);
+                    resolution.single_imports.remove(&import);
                 })
             });
             self.record_use(target, dummy_binding, Used::Other);
@@ -837,7 +837,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                         }
                         let key = BindingKey::new(target, ns);
                         this.update_resolution(parent, key, false, |_, resolution| {
-                            resolution.single_imports.shift_remove(&import);
+                            resolution.single_imports.remove(&import);
                         });
                     }
                 }

From 0ecb033d56ac15485ceee12b4aae15307b84d771 Mon Sep 17 00:00:00 2001
From: ismailarilik <arilik.ismail@gmail.com>
Date: Sun, 3 Nov 2024 16:17:43 +0300
Subject: [PATCH 13/15] Try to sort bindings before usage to have a stable
 result

The `FxIndexMap` solution seems costly.
---
 compiler/rustc_resolve/src/late.rs            | 16 ++++++----
 .../rustc_resolve/src/late/diagnostics.rs     | 30 ++++++++++++++++---
 2 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index e21f7be9a09ef..3e74ab19fa0de 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -259,7 +259,7 @@ impl RibKind<'_> {
 /// resolving, the name is looked up from inside out.
 #[derive(Debug)]
 pub(crate) struct Rib<'ra, R = Res> {
-    pub bindings: FxIndexMap<Ident, R>,
+    pub bindings: FxHashMap<Ident, R>,
     pub kind: RibKind<'ra>,
 }
 
@@ -1548,7 +1548,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                         // Allow all following defaults to refer to this type parameter.
                         forward_ty_ban_rib
                             .bindings
-                            .shift_remove(&Ident::with_dummy_span(param.ident.name));
+                            .remove(&Ident::with_dummy_span(param.ident.name));
                     }
                     GenericParamKind::Const { ref ty, kw_span: _, ref default } => {
                         // Const parameters can't have param bounds.
@@ -1576,7 +1576,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                         // Allow all following defaults to refer to this const parameter.
                         forward_const_ban_rib
                             .bindings
-                            .shift_remove(&Ident::with_dummy_span(param.ident.name));
+                            .remove(&Ident::with_dummy_span(param.ident.name));
                     }
                 }
             }
@@ -2795,8 +2795,12 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                         break;
                     }
 
-                    seen_bindings
-                        .extend(parent_rib.bindings.keys().map(|ident| (*ident, ident.span)));
+                    // It is sorted before usage so ordering is not important here.
+                    #[allow(rustc::potential_query_instability)]
+                    let mut idents: Vec<_> = parent_rib.bindings.keys().into_iter().collect();
+                    idents.sort_by_key(|&ident| ident.span);
+
+                    seen_bindings.extend(idents.into_iter().map(|ident| (*ident, ident.span)));
                 }
             }
 
@@ -3868,7 +3872,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
         }
     }
 
-    fn innermost_rib_bindings(&mut self, ns: Namespace) -> &mut FxIndexMap<Ident, Res> {
+    fn innermost_rib_bindings(&mut self, ns: Namespace) -> &mut FxHashMap<Ident, Res> {
         &mut self.ribs[ns].last_mut().unwrap().bindings
     }
 
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index 3f830661ba523..24bd116711922 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -762,7 +762,12 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
         if let Some(rib) = &self.last_block_rib
             && let RibKind::Normal = rib.kind
         {
-            for (ident, &res) in &rib.bindings {
+            // It is sorted before usage so ordering is not important here.
+            #[allow(rustc::potential_query_instability)]
+            let mut bindings: Vec<_> = rib.bindings.clone().into_iter().collect();
+            bindings.sort_by_key(|(ident, _)| ident.span);
+
+            for (ident, res) in &bindings {
                 if let Res::Local(_) = res
                     && path.len() == 1
                     && ident.span.eq_ctxt(path[0].ident.span)
@@ -944,7 +949,12 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
         if let Some(err_code) = err.code {
             if err_code == E0425 {
                 for label_rib in &self.label_ribs {
-                    for (label_ident, node_id) in &label_rib.bindings {
+                    // It is sorted before usage so ordering is not important here.
+                    #[allow(rustc::potential_query_instability)]
+                    let mut bindings: Vec<_> = label_rib.bindings.clone().into_iter().collect();
+                    bindings.sort_by_key(|(ident, _)| ident.span);
+
+                    for (label_ident, node_id) in &bindings {
                         let ident = path.last().unwrap().ident;
                         if format!("'{ident}") == label_ident.to_string() {
                             err.span_label(label_ident.span, "a label with a similar name exists");
@@ -2142,6 +2152,8 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
                 };
 
                 // Locals and type parameters
+                // `names` is sorted below so ordering is not important here.
+                #[allow(rustc::potential_query_instability)]
                 for (ident, &res) in &rib.bindings {
                     if filter_fn(res) && ident.span.ctxt() == rib_ctxt {
                         names.push(TypoSuggestion::typo_from_ident(*ident, res));
@@ -2605,18 +2617,28 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
         let within_scope = self.is_label_valid_from_rib(rib_index);
 
         let rib = &self.label_ribs[rib_index];
-        let names = rib
+        // `names` is sorted below so ordering is not important here.
+        #[allow(rustc::potential_query_instability)]
+        let mut names = rib
             .bindings
             .iter()
             .filter(|(id, _)| id.span.eq_ctxt(label.span))
             .map(|(id, _)| id.name)
             .collect::<Vec<Symbol>>();
 
+        // Make sure error reporting is deterministic.
+        names.sort();
+
         find_best_match_for_name(&names, label.name, None).map(|symbol| {
+            // It is sorted before usage so ordering is not important here.
+            #[allow(rustc::potential_query_instability)]
+            let mut bindings: Vec<_> = rib.bindings.clone().into_iter().collect();
+            bindings.sort_by_key(|(ident, _)| ident.span);
+
             // Upon finding a similar name, get the ident that it was from - the span
             // contained within helps make a useful diagnostic. In addition, determine
             // whether this candidate is within scope.
-            let (ident, _) = rib.bindings.iter().find(|(ident, _)| ident.name == symbol).unwrap();
+            let (ident, _) = bindings.iter().find(|(ident, _)| ident.name == symbol).unwrap();
             (*ident, within_scope)
         })
     }

From 2ff01e8b3c7f79adb31a25aaca174596b9a59a9d Mon Sep 17 00:00:00 2001
From: ismailarilik <arilik.ismail@gmail.com>
Date: Mon, 4 Nov 2024 09:15:40 +0300
Subject: [PATCH 14/15] Use `swap_remove` instead of `shift_remove`

`shift_remove` is very expensive
---
 compiler/rustc_resolve/src/ident.rs           |  7 +----
 compiler/rustc_resolve/src/imports.rs         |  8 ++---
 compiler/rustc_resolve/src/late.rs            | 16 ++++------
 .../rustc_resolve/src/late/diagnostics.rs     | 30 +++----------------
 4 files changed, 15 insertions(+), 46 deletions(-)

diff --git a/compiler/rustc_resolve/src/ident.rs b/compiler/rustc_resolve/src/ident.rs
index 0c06cc2e6a1db..b80e0e196ca08 100644
--- a/compiler/rustc_resolve/src/ident.rs
+++ b/compiler/rustc_resolve/src/ident.rs
@@ -984,14 +984,9 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
 
         // --- From now on we either have a glob resolution or no resolution. ---
 
-        // It is sorted before usage so ordering is not important.
-        #[allow(rustc::potential_query_instability)]
-        let mut single_imports: Vec<_> = resolution.single_imports.clone().into_iter().collect();
-        single_imports.sort_by_key(|import| import.0.id());
-
         // Check if one of single imports can still define the name,
         // if it can then our result is not determined and can be invalidated.
-        for single_import in &single_imports {
+        for single_import in &resolution.single_imports {
             if ignore_import == Some(*single_import) {
                 // This branch handles a cycle in single imports.
                 //
diff --git a/compiler/rustc_resolve/src/imports.rs b/compiler/rustc_resolve/src/imports.rs
index 51fbcb8ebb805..7db556ff48580 100644
--- a/compiler/rustc_resolve/src/imports.rs
+++ b/compiler/rustc_resolve/src/imports.rs
@@ -4,7 +4,7 @@ use std::cell::Cell;
 use std::mem;
 
 use rustc_ast::NodeId;
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
 use rustc_data_structures::intern::Interned;
 use rustc_errors::codes::*;
 use rustc_errors::{Applicability, MultiSpan, pluralize, struct_span_code_err};
@@ -220,7 +220,7 @@ impl<'ra> ImportData<'ra> {
 pub(crate) struct NameResolution<'ra> {
     /// Single imports that may define the name in the namespace.
     /// Imports are arena-allocated, so it's ok to use pointers as keys.
-    pub single_imports: FxHashSet<Import<'ra>>,
+    pub single_imports: FxIndexSet<Import<'ra>>,
     /// The least shadowable known binding for this name, or None if there are no known bindings.
     pub binding: Option<NameBinding<'ra>>,
     pub shadowed_glob: Option<NameBinding<'ra>>,
@@ -482,7 +482,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                 let key = BindingKey::new(target, ns);
                 let _ = this.try_define(import.parent_scope.module, key, dummy_binding, false);
                 this.update_resolution(import.parent_scope.module, key, false, |_, resolution| {
-                    resolution.single_imports.remove(&import);
+                    resolution.single_imports.swap_remove(&import);
                 })
             });
             self.record_use(target, dummy_binding, Used::Other);
@@ -837,7 +837,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                         }
                         let key = BindingKey::new(target, ns);
                         this.update_resolution(parent, key, false, |_, resolution| {
-                            resolution.single_imports.remove(&import);
+                            resolution.single_imports.swap_remove(&import);
                         });
                     }
                 }
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 3e74ab19fa0de..50cab538f143b 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -259,7 +259,7 @@ impl RibKind<'_> {
 /// resolving, the name is looked up from inside out.
 #[derive(Debug)]
 pub(crate) struct Rib<'ra, R = Res> {
-    pub bindings: FxHashMap<Ident, R>,
+    pub bindings: FxIndexMap<Ident, R>,
     pub kind: RibKind<'ra>,
 }
 
@@ -1548,7 +1548,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                         // Allow all following defaults to refer to this type parameter.
                         forward_ty_ban_rib
                             .bindings
-                            .remove(&Ident::with_dummy_span(param.ident.name));
+                            .swap_remove(&Ident::with_dummy_span(param.ident.name));
                     }
                     GenericParamKind::Const { ref ty, kw_span: _, ref default } => {
                         // Const parameters can't have param bounds.
@@ -1576,7 +1576,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                         // Allow all following defaults to refer to this const parameter.
                         forward_const_ban_rib
                             .bindings
-                            .remove(&Ident::with_dummy_span(param.ident.name));
+                            .swap_remove(&Ident::with_dummy_span(param.ident.name));
                     }
                 }
             }
@@ -2795,12 +2795,8 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                         break;
                     }
 
-                    // It is sorted before usage so ordering is not important here.
-                    #[allow(rustc::potential_query_instability)]
-                    let mut idents: Vec<_> = parent_rib.bindings.keys().into_iter().collect();
-                    idents.sort_by_key(|&ident| ident.span);
-
-                    seen_bindings.extend(idents.into_iter().map(|ident| (*ident, ident.span)));
+                    seen_bindings
+                        .extend(parent_rib.bindings.keys().map(|ident| (*ident, ident.span)));
                 }
             }
 
@@ -3872,7 +3868,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
         }
     }
 
-    fn innermost_rib_bindings(&mut self, ns: Namespace) -> &mut FxHashMap<Ident, Res> {
+    fn innermost_rib_bindings(&mut self, ns: Namespace) -> &mut FxIndexMap<Ident, Res> {
         &mut self.ribs[ns].last_mut().unwrap().bindings
     }
 
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index 24bd116711922..3f830661ba523 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -762,12 +762,7 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
         if let Some(rib) = &self.last_block_rib
             && let RibKind::Normal = rib.kind
         {
-            // It is sorted before usage so ordering is not important here.
-            #[allow(rustc::potential_query_instability)]
-            let mut bindings: Vec<_> = rib.bindings.clone().into_iter().collect();
-            bindings.sort_by_key(|(ident, _)| ident.span);
-
-            for (ident, res) in &bindings {
+            for (ident, &res) in &rib.bindings {
                 if let Res::Local(_) = res
                     && path.len() == 1
                     && ident.span.eq_ctxt(path[0].ident.span)
@@ -949,12 +944,7 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
         if let Some(err_code) = err.code {
             if err_code == E0425 {
                 for label_rib in &self.label_ribs {
-                    // It is sorted before usage so ordering is not important here.
-                    #[allow(rustc::potential_query_instability)]
-                    let mut bindings: Vec<_> = label_rib.bindings.clone().into_iter().collect();
-                    bindings.sort_by_key(|(ident, _)| ident.span);
-
-                    for (label_ident, node_id) in &bindings {
+                    for (label_ident, node_id) in &label_rib.bindings {
                         let ident = path.last().unwrap().ident;
                         if format!("'{ident}") == label_ident.to_string() {
                             err.span_label(label_ident.span, "a label with a similar name exists");
@@ -2152,8 +2142,6 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
                 };
 
                 // Locals and type parameters
-                // `names` is sorted below so ordering is not important here.
-                #[allow(rustc::potential_query_instability)]
                 for (ident, &res) in &rib.bindings {
                     if filter_fn(res) && ident.span.ctxt() == rib_ctxt {
                         names.push(TypoSuggestion::typo_from_ident(*ident, res));
@@ -2617,28 +2605,18 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
         let within_scope = self.is_label_valid_from_rib(rib_index);
 
         let rib = &self.label_ribs[rib_index];
-        // `names` is sorted below so ordering is not important here.
-        #[allow(rustc::potential_query_instability)]
-        let mut names = rib
+        let names = rib
             .bindings
             .iter()
             .filter(|(id, _)| id.span.eq_ctxt(label.span))
             .map(|(id, _)| id.name)
             .collect::<Vec<Symbol>>();
 
-        // Make sure error reporting is deterministic.
-        names.sort();
-
         find_best_match_for_name(&names, label.name, None).map(|symbol| {
-            // It is sorted before usage so ordering is not important here.
-            #[allow(rustc::potential_query_instability)]
-            let mut bindings: Vec<_> = rib.bindings.clone().into_iter().collect();
-            bindings.sort_by_key(|(ident, _)| ident.span);
-
             // Upon finding a similar name, get the ident that it was from - the span
             // contained within helps make a useful diagnostic. In addition, determine
             // whether this candidate is within scope.
-            let (ident, _) = bindings.iter().find(|(ident, _)| ident.name == symbol).unwrap();
+            let (ident, _) = rib.bindings.iter().find(|(ident, _)| ident.name == symbol).unwrap();
             (*ident, within_scope)
         })
     }

From 0944d8c1ea3bdcc40b14605a4c884acfb0f50853 Mon Sep 17 00:00:00 2001
From: ismailarilik <arilik.ismail@gmail.com>
Date: Mon, 4 Nov 2024 09:25:12 +0300
Subject: [PATCH 15/15] Sort `idents` before usage instead of `suggestions` to
 have a stable order

As requested by @petrochenkov
---
 compiler/rustc_resolve/src/diagnostics.rs | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index b6417b654f206..b5ae6ed4cda2f 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -1366,9 +1366,12 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         );
 
         if lookup_ident.span.at_least_rust_2018() {
-            // Extended suggestions will be sorted at the end of this function.
+            // `idents` is sorted before usage so ordering is not important here.
             #[allow(rustc::potential_query_instability)]
-            for ident in self.extern_prelude.clone().into_keys() {
+            let mut idents: Vec<_> = self.extern_prelude.clone().into_keys().collect();
+            idents.sort_by_key(|ident| ident.span);
+
+            for ident in idents {
                 if ident.span.from_expansion() {
                     // Idents are adjusted to the root context before being
                     // resolved in the extern prelude, so reporting this to the
@@ -1422,8 +1425,6 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             }
         }
 
-        // Make sure error reporting is deterministic.
-        suggestions.sort_by_key(|suggestion| suggestion.did.unwrap().index);
         suggestions
     }