Replace a number of FxHashMaps/Sets with stable-iteration-order alternatives.

compiler/rustc_hir_analysis/src/astconv/errors.rs

@@ -6,6 +6,7 @@ use crate::errors::{
 use crate::fluent_generated as fluent;
 use crate::traits::error_reporting::report_object_safety_error;
 use rustc_data_structures::fx::{FxHashMap, FxIndexMap, FxIndexSet};
+use rustc_data_structures::unord::UnordMap;
 use rustc_errors::{pluralize, struct_span_err, Applicability, Diagnostic, ErrorGuaranteed};
 use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LocalDefId};
@@ -673,7 +674,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 }))
             })
             .flatten()
-            .collect::<FxHashMap<Symbol, &ty::AssocItem>>();
+            .collect::<UnordMap<Symbol, &ty::AssocItem>>();
 
         let mut names = names
             .into_iter()
@@ -709,7 +710,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         let mut where_constraints = vec![];
         let mut already_has_generics_args_suggestion = false;
         for (span, assoc_items) in &associated_types {
-            let mut names: FxHashMap<_, usize> = FxHashMap::default();
+            let mut names: UnordMap<_, usize> = Default::default();
             for item in assoc_items {
                 types_count += 1;
                 *names.entry(item.name).or_insert(0) += 1;

compiler/rustc_hir_analysis/src/collect.rs

@@ -16,6 +16,7 @@
 
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::unord::UnordMap;
 use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed, StashKey};
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
@@ -979,7 +980,7 @@ fn trait_def(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::TraitDef {
         })
         // Check for duplicates
         .and_then(|list| {
-            let mut set: FxHashMap<Symbol, Span> = FxHashMap::default();
+            let mut set: UnordMap<Symbol, Span> = Default::default();
             let mut no_dups = true;
 
             for ident in &*list {

compiler/rustc_lint/src/foreign_modules.rs

@@ -1,5 +1,5 @@
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::stack::ensure_sufficient_stack;
+use rustc_data_structures::unord::{UnordMap, UnordSet};
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
 use rustc_middle::query::Providers;
@@ -72,7 +72,7 @@ struct ClashingExternDeclarations {
     /// the symbol should be reported as a clashing declaration.
     // FIXME: Technically, we could just store a &'tcx str here without issue; however, the
     // `impl_lint_pass` macro doesn't currently support lints parametric over a lifetime.
-    seen_decls: FxHashMap<Symbol, hir::OwnerId>,
+    seen_decls: UnordMap<Symbol, hir::OwnerId>,
 }
 
 /// Differentiate between whether the name for an extern decl came from the link_name attribute or
@@ -96,7 +96,7 @@ impl SymbolName {
 
 impl ClashingExternDeclarations {
     pub(crate) fn new() -> Self {
-        ClashingExternDeclarations { seen_decls: FxHashMap::default() }
+        ClashingExternDeclarations { seen_decls: Default::default() }
     }
 
     /// Insert a new foreign item into the seen set. If a symbol with the same name already exists
@@ -209,12 +209,12 @@ fn structurally_same_type<'tcx>(
     b: Ty<'tcx>,
     ckind: types::CItemKind,
 ) -> bool {
-    let mut seen_types = FxHashSet::default();
+    let mut seen_types = UnordSet::default();
     structurally_same_type_impl(&mut seen_types, tcx, param_env, a, b, ckind)
 }
 
 fn structurally_same_type_impl<'tcx>(
-    seen_types: &mut FxHashSet<(Ty<'tcx>, Ty<'tcx>)>,
+    seen_types: &mut UnordSet<(Ty<'tcx>, Ty<'tcx>)>,
     tcx: TyCtxt<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     a: Ty<'tcx>,

compiler/rustc_lint/src/non_ascii_idents.rs

@@ -4,7 +4,8 @@ use crate::lints::{
 };
 use crate::{EarlyContext, EarlyLintPass, LintContext};
 use rustc_ast as ast;
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::FxIndexMap;
+use rustc_data_structures::unord::UnordMap;
 use rustc_span::symbol::Symbol;
 
 declare_lint! {
@@ -194,8 +195,8 @@ impl EarlyLintPass for NonAsciiIdents {
         }
 
         if has_non_ascii_idents && check_confusable_idents {
-            let mut skeleton_map: FxHashMap<Symbol, (Symbol, Span, bool)> =
+            let mut skeleton_map: UnordMap<Symbol, (Symbol, Span, bool)> =
-                FxHashMap::with_capacity_and_hasher(symbols.len(), Default::default());
+                UnordMap::with_capacity(symbols.len());
             let mut skeleton_buf = String::new();
 
             for (&symbol, &sp) in symbols.iter() {
@@ -248,8 +249,8 @@ impl EarlyLintPass for NonAsciiIdents {
                 Verified,
             }
 
-            let mut script_states: FxHashMap<AugmentedScriptSet, ScriptSetUsage> =
+            let mut script_states: FxIndexMap<AugmentedScriptSet, ScriptSetUsage> =
-                FxHashMap::default();
+                Default::default();
             let latin_augmented_script_set = AugmentedScriptSet::for_char('A');
             script_states.insert(latin_augmented_script_set, ScriptSetUsage::Verified);
 

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1914,14 +1914,15 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         empty_proc_macro!(self);
         let tcx = self.tcx;
         let lib_features = tcx.lib_features(LOCAL_CRATE);
-        self.lazy_array(lib_features.to_vec())
+        self.lazy_array(lib_features.to_sorted_vec())
     }
 
     fn encode_stability_implications(&mut self) -> LazyArray<(Symbol, Symbol)> {
         empty_proc_macro!(self);
         let tcx = self.tcx;
         let implications = tcx.stability_implications(LOCAL_CRATE);
-        self.lazy_array(implications.iter().map(|(k, v)| (*k, *v)))
+        let sorted = implications.to_sorted_stable_ord();
+        self.lazy_array(sorted.into_iter().map(|(k, v)| (*k, *v)))
     }
 
     fn encode_diagnostic_items(&mut self) -> LazyArray<(Symbol, DefIndex)> {

compiler/rustc_middle/src/middle/mod.rs

@@ -4,7 +4,7 @@ pub mod dependency_format;
 pub mod exported_symbols;
 pub mod lang_items;
 pub mod lib_features {
-    use rustc_data_structures::fx::FxHashMap;
+    use rustc_data_structures::unord::UnordMap;
     use rustc_span::{symbol::Symbol, Span};
 
     #[derive(Copy, Clone, Debug, PartialEq, Eq)]
@@ -16,15 +16,16 @@ pub mod lib_features {
 
     #[derive(HashStable, Debug, Default)]
     pub struct LibFeatures {
-        pub stability: FxHashMap<Symbol, (FeatureStability, Span)>,
+        pub stability: UnordMap<Symbol, (FeatureStability, Span)>,
     }
 
     impl LibFeatures {
-        pub fn to_vec(&self) -> Vec<(Symbol, FeatureStability)> {
+        pub fn to_sorted_vec(&self) -> Vec<(Symbol, FeatureStability)> {
-            let mut all_features: Vec<_> =
+            self.stability
-                self.stability.iter().map(|(&sym, &(stab, _))| (sym, stab)).collect();
+                .to_sorted_stable_ord()
-            all_features.sort_unstable_by(|(a, _), (b, _)| a.as_str().cmp(b.as_str()));
+                .iter()
-            all_features
+                .map(|(&sym, &(stab, _))| (sym, stab))
+                .collect()
         }
     }
 }

compiler/rustc_middle/src/middle/stability.rs

@@ -9,6 +9,7 @@ use rustc_attr::{
     self as attr, ConstStability, DefaultBodyStability, DeprecatedSince, Deprecation, Stability,
 };
 use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::unord::UnordMap;
 use rustc_errors::{Applicability, Diagnostic};
 use rustc_feature::GateIssue;
 use rustc_hir::def::DefKind;
@@ -77,7 +78,7 @@ pub struct Index {
     /// to know that the feature implies another feature. If it were reversed, and the `#[stable]`
     /// attribute had an `implies` meta item, then a map would be necessary when avoiding a "use of
     /// unstable feature" error for a feature that was implied.
-    pub implications: FxHashMap<Symbol, Symbol>,
+    pub implications: UnordMap<Symbol, Symbol>,
 }
 
 impl Index {

compiler/rustc_middle/src/query/mod.rs

@@ -61,7 +61,7 @@ use rustc_data_structures::fx::{FxHashMap, FxIndexMap, FxIndexSet};
 use rustc_data_structures::steal::Steal;
 use rustc_data_structures::svh::Svh;
 use rustc_data_structures::sync::Lrc;
-use rustc_data_structures::unord::UnordSet;
+use rustc_data_structures::unord::{UnordMap, UnordSet};
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, DocLinkResMap};
@@ -1739,7 +1739,7 @@ rustc_queries! {
         separate_provide_extern
         arena_cache
     }
-    query stability_implications(_: CrateNum) -> &'tcx FxHashMap<Symbol, Symbol> {
+    query stability_implications(_: CrateNum) -> &'tcx UnordMap<Symbol, Symbol> {
         arena_cache
         desc { "calculating the implications between `#[unstable]` features defined in a crate" }
         separate_provide_extern

compiler/rustc_passes/src/stability.rs

@@ -6,7 +6,8 @@ use rustc_attr::{
     self as attr, ConstStability, DeprecatedSince, Stability, StabilityLevel, StableSince,
     Unstable, UnstableReason, VERSION_PLACEHOLDER,
 };
-use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
+use rustc_data_structures::fx::FxIndexMap;
+use rustc_data_structures::unord::{ExtendUnord, UnordMap, UnordSet};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{LocalDefId, LocalModDefId, CRATE_DEF_ID, LOCAL_CRATE};
@@ -923,7 +924,7 @@ pub fn check_unused_or_stable_features(tcx: TyCtxt<'_>) {
     }
 
     let declared_lang_features = &tcx.features().declared_lang_features;
-    let mut lang_features = FxHashSet::default();
+    let mut lang_features = UnordSet::default();
     for &(feature, span, since) in declared_lang_features {
         if let Some(since) = since {
             // Warn if the user has enabled an already-stable lang feature.
@@ -980,11 +981,11 @@ pub fn check_unused_or_stable_features(tcx: TyCtxt<'_>) {
     fn check_features<'tcx>(
         tcx: TyCtxt<'tcx>,
         remaining_lib_features: &mut FxIndexMap<&Symbol, Span>,
-        remaining_implications: &mut FxHashMap<Symbol, Symbol>,
+        remaining_implications: &mut UnordMap<Symbol, Symbol>,
         defined_features: &LibFeatures,
-        all_implications: &FxHashMap<Symbol, Symbol>,
+        all_implications: &UnordMap<Symbol, Symbol>,
     ) {
-        for (feature, since) in defined_features.to_vec() {
+        for (feature, since) in defined_features.to_sorted_vec() {
             if let FeatureStability::AcceptedSince(since) = since
                 && let Some(span) = remaining_lib_features.get(&feature)
             {
@@ -1021,7 +1022,8 @@ pub fn check_unused_or_stable_features(tcx: TyCtxt<'_>) {
         // `remaining_lib_features`.
         let mut all_implications = remaining_implications.clone();
         for &cnum in tcx.crates(()) {
-            all_implications.extend(tcx.stability_implications(cnum));
+            all_implications
+                .extend_unord(tcx.stability_implications(cnum).items().map(|(k, v)| (*k, *v)));
         }
 
         check_features(
@@ -1052,8 +1054,7 @@ pub fn check_unused_or_stable_features(tcx: TyCtxt<'_>) {
 
     // We only use the hash map contents to emit errors, and the order of
     // emitted errors do not affect query stability.
-    #[allow(rustc::potential_query_instability)]
+    for (&implied_by, &feature) in remaining_implications.to_sorted_stable_ord() {
-    for (implied_by, feature) in remaining_implications {
         let local_defined_features = tcx.lib_features(LOCAL_CRATE);
         let span = local_defined_features
             .stability