Use a Set<T> instead of a Map<T, bool>

src/librustc/middle/expr_use_visitor.rs

@@ -31,7 +31,7 @@ use std::rc::Rc;
 use syntax::ast;
 use syntax::ptr::P;
 use syntax_pos::Span;
-use util::nodemap::ItemLocalMap;
+use util::nodemap::ItemLocalSet;
 
 ///////////////////////////////////////////////////////////////////////////
 // The Delegate trait
@@ -279,7 +279,7 @@ impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx, 'tcx> {
                param_env: ty::ParamEnv<'tcx>,
                region_scope_tree: &'a region::ScopeTree,
                tables: &'a ty::TypeckTables<'tcx>,
-               rvalue_promotable_map: Option<Rc<ItemLocalMap<bool>>>)
+               rvalue_promotable_map: Option<Rc<ItemLocalSet>>)
                -> Self
     {
         ExprUseVisitor {

src/librustc/middle/mem_categorization.rs

@@ -86,7 +86,7 @@ use syntax_pos::Span;
 
 use std::fmt;
 use std::rc::Rc;
-use util::nodemap::ItemLocalMap;
+use util::nodemap::ItemLocalSet;
 
 #[derive(Clone, PartialEq)]
 pub enum Categorization<'tcx> {
@@ -286,7 +286,7 @@ pub struct MemCategorizationContext<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
     pub tcx: TyCtxt<'a, 'gcx, 'tcx>,
     pub region_scope_tree: &'a region::ScopeTree,
     pub tables: &'a ty::TypeckTables<'tcx>,
-    rvalue_promotable_map: Option<Rc<ItemLocalMap<bool>>>,
+    rvalue_promotable_map: Option<Rc<ItemLocalSet>>,
     infcx: Option<&'a InferCtxt<'a, 'gcx, 'tcx>>,
 }
 
@@ -395,7 +395,7 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx, 'tcx> {
     pub fn new(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                region_scope_tree: &'a region::ScopeTree,
                tables: &'a ty::TypeckTables<'tcx>,
-               rvalue_promotable_map: Option<Rc<ItemLocalMap<bool>>>)
+               rvalue_promotable_map: Option<Rc<ItemLocalSet>>)
                -> MemCategorizationContext<'a, 'tcx, 'tcx> {
         MemCategorizationContext {
             tcx,
@@ -897,7 +897,7 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
                            expr_ty: Ty<'tcx>)
                            -> cmt<'tcx> {
         let hir_id = self.tcx.hir.node_to_hir_id(id);
-        let promotable = self.rvalue_promotable_map.as_ref().map(|m| m[&hir_id.local_id])
+        let promotable = self.rvalue_promotable_map.as_ref().map(|m| m.contains(&hir_id.local_id))
                                                             .unwrap_or(false);
 
         // Always promote `[T; 0]` (even when e.g. borrowed mutably).

src/librustc/ty/maps/mod.rs

@@ -37,7 +37,7 @@ use ty::{self, CrateInherentImpls, Ty, TyCtxt};
 use ty::layout::{Layout, LayoutError};
 use ty::steal::Steal;
 use ty::subst::Substs;
-use util::nodemap::{DefIdSet, DefIdMap, ItemLocalMap};
+use util::nodemap::{DefIdSet, DefIdMap, ItemLocalSet};
 use util::common::{profq_msg, ProfileQueriesMsg};
 
 use rustc_data_structures::indexed_set::IdxSetBuf;
@@ -236,7 +236,7 @@ define_maps! { <'tcx>
     [] fn is_exported_symbol: IsExportedSymbol(DefId) -> bool,
     [] fn item_body_nested_bodies: ItemBodyNestedBodies(DefId) -> ExternBodyNestedBodies,
     [] fn const_is_rvalue_promotable_to_static: ConstIsRvaluePromotableToStatic(DefId) -> bool,
-    [] fn rvalue_promotable_map: RvaluePromotableMap(DefId) -> Rc<ItemLocalMap<bool>>,
+    [] fn rvalue_promotable_map: RvaluePromotableMap(DefId) -> Rc<ItemLocalSet>,
     [] fn is_mir_available: IsMirAvailable(DefId) -> bool,
     [] fn vtable_methods: vtable_methods_node(ty::PolyTraitRef<'tcx>)
                           -> Rc<Vec<Option<(DefId, &'tcx Substs<'tcx>)>>>,

src/librustc/util/nodemap.rs

@@ -25,10 +25,12 @@ pub type ItemLocalMap<T> = FxHashMap<ItemLocalId, T>;
 
 pub type NodeSet = FxHashSet<ast::NodeId>;
 pub type DefIdSet = FxHashSet<DefId>;
+pub type ItemLocalSet = FxHashSet<ItemLocalId>;
 
 pub fn NodeMap<T>() -> NodeMap<T> { FxHashMap() }
 pub fn DefIdMap<T>() -> DefIdMap<T> { FxHashMap() }
 pub fn ItemLocalMap<T>() -> ItemLocalMap<T> { FxHashMap() }
 pub fn NodeSet() -> NodeSet { FxHashSet() }
 pub fn DefIdSet() -> DefIdSet { FxHashSet() }
+pub fn ItemLocalSet() -> ItemLocalSet { FxHashSet() }
 

src/librustc_passes/consts.rs

@@ -43,7 +43,7 @@ use rustc::ty::maps::{queries, Providers};
 use rustc::ty::subst::Substs;
 use rustc::traits::Reveal;
 use rustc::util::common::ErrorReported;
-use rustc::util::nodemap::{ItemLocalMap, NodeSet};
+use rustc::util::nodemap::{ItemLocalSet, NodeSet};
 use rustc::lint::builtin::CONST_ERR;
 use rustc::hir::{self, PatKind, RangeEnd};
 use std::rc::Rc;
@@ -79,12 +79,12 @@ fn const_is_rvalue_promotable_to_static<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                      .expect("rvalue_promotable_map invoked with non-local def-id");
     let body_id = tcx.hir.body_owned_by(node_id);
     let body_hir_id = tcx.hir.node_to_hir_id(body_id.node_id);
-    tcx.rvalue_promotable_map(def_id).contains_key(&body_hir_id.local_id)
+    tcx.rvalue_promotable_map(def_id).contains(&body_hir_id.local_id)
 }
 
 fn rvalue_promotable_map<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                    def_id: DefId)
-                                   -> Rc<ItemLocalMap<bool>>
+                                   -> Rc<ItemLocalSet>
 {
     let outer_def_id = tcx.closure_base_def_id(def_id);
     if outer_def_id != def_id {
@@ -100,7 +100,7 @@ fn rvalue_promotable_map<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         mut_rvalue_borrows: NodeSet(),
         param_env: ty::ParamEnv::empty(Reveal::UserFacing),
         identity_substs: Substs::empty(),
-        result_map: ItemLocalMap(),
+        result: ItemLocalSet(),
     };
 
     // `def_id` should be a `Body` owner
@@ -109,7 +109,7 @@ fn rvalue_promotable_map<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     let body_id = tcx.hir.body_owned_by(node_id);
     visitor.visit_nested_body(body_id);
 
-    Rc::new(visitor.result_map)
+    Rc::new(visitor.result)
 }
 
 struct CheckCrateVisitor<'a, 'tcx: 'a> {
@@ -121,7 +121,7 @@ struct CheckCrateVisitor<'a, 'tcx: 'a> {
     param_env: ty::ParamEnv<'tcx>,
     identity_substs: &'tcx Substs<'tcx>,
     tables: &'a ty::TypeckTables<'tcx>,
-    result_map: ItemLocalMap<bool>,
+    result: ItemLocalSet,
 }
 
 impl<'a, 'gcx> CheckCrateVisitor<'a, 'gcx> {
@@ -322,7 +322,9 @@ impl<'a, 'tcx> Visitor<'tcx> for CheckCrateVisitor<'a, 'tcx> {
             }
         }
 
-        self.result_map.insert(ex.hir_id.local_id, self.promotable);
+        if self.promotable {
+            self.result.insert(ex.hir_id.local_id);
+        }
         self.promotable &= outer;
     }
 }