From 363a56bd9049bd4bbadea6a566b4ef0b5ac30094 Mon Sep 17 00:00:00 2001
From: Inokentiy Babushkin <twk@twki.de>
Date: Sun, 23 Jul 2017 17:29:57 +0200
Subject: [PATCH] Implemented crate tracking mechanism for #17.

---
 src/semcheck/mapping.rs  | 27 +++++++++++++++++++++++++--
 src/semcheck/mismatch.rs | 10 +++-------
 src/semcheck/traverse.rs |  4 ++--
 3 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/src/semcheck/mapping.rs b/src/semcheck/mapping.rs
index 6cbef888a9596..fc26922d8cf82 100644
--- a/src/semcheck/mapping.rs
+++ b/src/semcheck/mapping.rs
@@ -4,7 +4,7 @@
 //! map used to temporarily match up unsorted item sequences' elements by name.
 
 use rustc::hir::def::{Def, Export};
-use rustc::hir::def_id::DefId;
+use rustc::hir::def_id::{CrateNum, DefId};
 use rustc::ty::TypeParameterDef;
 
 use std::collections::{BTreeSet, HashMap, VecDeque};
@@ -16,8 +16,11 @@ use syntax::ast::Name;
 /// Definitions and simple `DefId` mappings are kept separate to record both kinds of
 /// correspondence losslessly. The *access* to the stored data happens through the same API,
 /// however.
-#[derive(Default)]
 pub struct IdMapping {
+    /// The old crate.
+    old_crate: CrateNum,
+    /// The new crate.
+    new_crate: CrateNum,
     /// Toplevel items' old `DefId` mapped to old and new `Def`.
     toplevel_mapping: HashMap<DefId, (Def, Def)>,
     /// Trait items' old `DefId` mapped to old and new `Def`.
@@ -31,6 +34,18 @@ pub struct IdMapping {
 }
 
 impl IdMapping {
+    pub fn new(old_crate: CrateNum, new_crate: CrateNum) -> IdMapping {
+        IdMapping {
+            old_crate: old_crate,
+            new_crate: new_crate,
+            toplevel_mapping: HashMap::new(),
+            trait_item_mapping: HashMap::new(),
+            internal_mapping: HashMap::new(),
+            child_mapping: HashMap::new(),
+            type_params: HashMap::new(),
+        }
+    }
+
     /// Register two exports representing the same item across versions.
     pub fn add_export(&mut self, old: Def, new: Def) -> bool {
         if self.toplevel_mapping.contains_key(&old.def_id()) {
@@ -132,6 +147,14 @@ impl IdMapping {
             .get(&parent)
             .map(|m| m.iter().map(move |old| (*old, self.internal_mapping[old])))
     }
+
+    pub fn in_old_crate(&self, did: DefId) -> bool {
+        self.old_crate == did.krate
+    }
+
+    pub fn in_new_crate(&self, did: DefId) -> bool {
+        self.new_crate == did.krate
+    }
 }
 
 /// A mapping from names to pairs of old and new exports.
diff --git a/src/semcheck/mismatch.rs b/src/semcheck/mismatch.rs
index 3f03cb9181a21..caf78435f378a 100644
--- a/src/semcheck/mismatch.rs
+++ b/src/semcheck/mismatch.rs
@@ -4,7 +4,7 @@
 //! essentially just renamed instances of the same item (as long as they are both unknown to us
 //! at the time of analysis). Thus, we may match them up to avoid some false positives.
 
-use rustc::hir::def_id::{CrateNum, DefId};
+use rustc::hir::def_id::DefId;
 use rustc::ty;
 use rustc::ty::{Ty, TyCtxt};
 use rustc::ty::Visibility::Public;
@@ -27,20 +27,17 @@ pub struct Mismatch<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
     item_queue: VecDeque<(DefId, DefId)>,
     /// The id mapping to use.
     id_mapping: &'a mut IdMapping,
-    /// The old crate.
-    old_crate: CrateNum,
 }
 
 impl<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> Mismatch<'a, 'gcx, 'tcx> {
     /// Construct a new mismtach type relation.
-    pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>, old_crate: CrateNum, id_mapping: &'a mut IdMapping)
+    pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>, id_mapping: &'a mut IdMapping)
         -> Mismatch<'a, 'gcx, 'tcx>
     {
         Mismatch {
             tcx: tcx,
             item_queue: id_mapping.toplevel_queue(),
             id_mapping: id_mapping,
-            old_crate: old_crate,
         }
     }
 
@@ -191,8 +188,7 @@ impl<'a, 'gcx, 'tcx> TypeRelation<'a, 'gcx, 'tcx> for Mismatch<'a, 'gcx, 'tcx> {
         };
 
         if let Some((old_def_id, new_def_id)) = matching {
-            // TODO: implement proper crate tracking and fix this then.
-            if !self.id_mapping.contains_id(old_def_id) && old_def_id.krate == self.old_crate {
+            if !self.id_mapping.contains_id(old_def_id) && self.id_mapping.in_old_crate(old_def_id) {
                 self.id_mapping.add_internal_item(old_def_id, new_def_id);
                 self.item_queue.push_back((old_def_id, new_def_id));
             }
diff --git a/src/semcheck/traverse.rs b/src/semcheck/traverse.rs
index 2e5860de44e7d..fc08e411c256b 100644
--- a/src/semcheck/traverse.rs
+++ b/src/semcheck/traverse.rs
@@ -31,14 +31,14 @@ pub fn run_analysis<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, old: DefId, new: DefI
     -> ChangeSet<'tcx>
 {
     let mut changes = Default::default();
-    let mut id_mapping = Default::default();
+    let mut id_mapping = IdMapping::new(old.krate, new.krate);
 
     // first pass
     diff_structure(&mut changes, &mut id_mapping, tcx, old, new);
 
     // second pass
     {
-        let mut mismatch = Mismatch::new(tcx, old.krate, &mut id_mapping);
+        let mut mismatch = Mismatch::new(tcx, &mut id_mapping);
         mismatch.process();
     }