From fffe9fbb5134da7ce77660dfc4562b5e395853e8 Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Sat, 23 Jun 2018 19:27:28 +0300
Subject: [PATCH] hygiene: More descriptive names for things involved in late
 hygienic name resolution

---
 src/librustc/hir/map/definitions.rs | 31 +++++++++++++++++------------
 src/librustc/ty/mod.rs              | 11 +++++-----
 src/librustc_resolve/macros.rs      |  3 ++-
 3 files changed, 26 insertions(+), 19 deletions(-)

diff --git a/src/librustc/hir/map/definitions.rs b/src/librustc/hir/map/definitions.rs
index b1cb9d7fbd4..b2365e22cc6 100644
--- a/src/librustc/hir/map/definitions.rs
+++ b/src/librustc/hir/map/definitions.rs
@@ -157,8 +157,13 @@ pub struct Definitions {
     node_to_def_index: NodeMap<DefIndex>,
     def_index_to_node: [Vec<ast::NodeId>; 2],
     pub(super) node_to_hir_id: IndexVec<ast::NodeId, hir::HirId>,
-    macro_def_scopes: FxHashMap<Mark, DefId>,
-    expansions: FxHashMap<DefIndex, Mark>,
+    /// If `Mark` is an ID of some macro expansion,
+    /// then `DefId` is the normal module (`mod`) in which the expanded macro was defined.
+    parent_modules_of_macro_defs: FxHashMap<Mark, DefId>,
+    /// Item with a given `DefIndex` was defined during opaque macro expansion with ID `Mark`.
+    /// It can actually be defined during transparent macro expansions inside that opaque expansion,
+    /// but transparent expansions are ignored here.
+    opaque_expansions_that_defined: FxHashMap<DefIndex, Mark>,
     next_disambiguator: FxHashMap<(DefIndex, DefPathData), u32>,
     def_index_to_span: FxHashMap<DefIndex, Span>,
 }
@@ -175,8 +180,8 @@ impl Clone for Definitions {
                 self.def_index_to_node[1].clone(),
             ],
             node_to_hir_id: self.node_to_hir_id.clone(),
-            macro_def_scopes: self.macro_def_scopes.clone(),
-            expansions: self.expansions.clone(),
+            parent_modules_of_macro_defs: self.parent_modules_of_macro_defs.clone(),
+            opaque_expansions_that_defined: self.opaque_expansions_that_defined.clone(),
             next_disambiguator: self.next_disambiguator.clone(),
             def_index_to_span: self.def_index_to_span.clone(),
         }
@@ -397,8 +402,8 @@ impl Definitions {
             node_to_def_index: NodeMap(),
             def_index_to_node: [vec![], vec![]],
             node_to_hir_id: IndexVec::new(),
-            macro_def_scopes: FxHashMap(),
-            expansions: FxHashMap(),
+            parent_modules_of_macro_defs: FxHashMap(),
+            opaque_expansions_that_defined: FxHashMap(),
             next_disambiguator: FxHashMap(),
             def_index_to_span: FxHashMap(),
         }
@@ -580,7 +585,7 @@ impl Definitions {
 
         let expansion = expansion.modern();
         if expansion != Mark::root() {
-            self.expansions.insert(index, expansion);
+            self.opaque_expansions_that_defined.insert(index, expansion);
         }
 
         // The span is added if it isn't DUMMY_SP
@@ -600,16 +605,16 @@ impl Definitions {
         self.node_to_hir_id = mapping;
     }
 
-    pub fn expansion(&self, index: DefIndex) -> Mark {
-        self.expansions.get(&index).cloned().unwrap_or(Mark::root())
+    pub fn opaque_expansion_that_defined(&self, index: DefIndex) -> Mark {
+        self.opaque_expansions_that_defined.get(&index).cloned().unwrap_or(Mark::root())
     }
 
-    pub fn macro_def_scope(&self, mark: Mark) -> DefId {
-        self.macro_def_scopes[&mark]
+    pub fn parent_module_of_macro_def(&self, mark: Mark) -> DefId {
+        self.parent_modules_of_macro_defs[&mark]
     }
 
-    pub fn add_macro_def_scope(&mut self, mark: Mark, scope: DefId) {
-        self.macro_def_scopes.insert(mark, scope);
+    pub fn add_parent_module_of_macro_def(&mut self, mark: Mark, module: DefId) {
+        self.parent_modules_of_macro_defs.insert(mark, module);
     }
 }
 
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index 4f5f0c9d740..ce709831455 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -2732,13 +2732,14 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
     }
 
     pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
-        let expansion = match scope.krate {
-            LOCAL_CRATE => self.hir.definitions().expansion(scope.index),
+        ident = ident.modern();
+        let target_expansion = match scope.krate {
+            LOCAL_CRATE => self.hir.definitions().opaque_expansion_that_defined(scope.index),
             _ => Mark::root(),
         };
-        ident = ident.modern();
-        let scope = match ident.span.adjust(expansion) {
-            Some(macro_def) => self.hir.definitions().macro_def_scope(macro_def),
+        let scope = match ident.span.adjust(target_expansion) {
+            Some(actual_expansion) =>
+                self.hir.definitions().parent_module_of_macro_def(actual_expansion),
             None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
             None => self.hir.get_module_parent(block),
         };
diff --git a/src/librustc_resolve/macros.rs b/src/librustc_resolve/macros.rs
index 1c49e8f4753..ebdaa456170 100644
--- a/src/librustc_resolve/macros.rs
+++ b/src/librustc_resolve/macros.rs
@@ -327,7 +327,8 @@ impl<'a> base::Resolver for Resolver<'a> {
         self.macro_defs.insert(invoc.expansion_data.mark, def_id);
         let normal_module_def_id =
             self.macro_def_scope(invoc.expansion_data.mark).normal_ancestor_id;
-        self.definitions.add_macro_def_scope(invoc.expansion_data.mark, normal_module_def_id);
+        self.definitions.add_parent_module_of_macro_def(invoc.expansion_data.mark,
+                                                        normal_module_def_id);
 
         self.unused_macros.remove(&def_id);
         let ext = self.get_macro(def);