Fix instability in SVH and DefPathHash computation.

Author: michaelwoerister

src/librustc/hir/map/collector.rs

@@ -142,7 +142,7 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
             });
 
         let mut upstream_crates: Vec<_> = cstore.crates_untracked().iter().map(|&cnum| {
-            let name = cstore.crate_name_untracked(cnum).as_str();
+            let name = cstore.crate_name_untracked(cnum).as_str().to_owned();
             let disambiguator = cstore.crate_disambiguator_untracked(cnum)
                                       .to_fingerprint();
             let hash = cstore.crate_hash_untracked(cnum);

src/librustc/hir/map/definitions.rs

@@ -220,7 +220,7 @@ impl DefKey {
             DefPathData::EnumVariant(name) |
             DefPathData::Field(name) |
             DefPathData::GlobalMetaData(name) => {
-                name.hash(&mut hasher);
+                (&name[..]).hash(&mut hasher);
             }
 
             DefPathData::Impl |

src/librustc_trans_utils/symbol_names.rs

@@ -194,7 +194,7 @@ fn get_symbol_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         }
 
         if avoid_cross_crate_conflicts {
-            hasher.hash(tcx.crate_name.as_str());
+            hasher.hash(&tcx.crate_name.as_str()[..]);
             hasher.hash(tcx.sess.local_crate_disambiguator());
         }
     });