---

yaml
---
r: 224364
b: refs/heads/beta
c: e99b53e
h: refs/heads/master
v: v3

Author: Ariel Ben-Yehuda

[refs]

@@ -23,7 +23,7 @@ refs/tags/0.9: 36870b185fc5f5486636d4515f0e22677493f225
 refs/tags/0.10: ac33f2b15782272ae348dbd7b14b8257b2148b5a
 refs/tags/0.11.0: e1247cb1d0d681be034adb4b558b5a0c0d5720f9
 refs/tags/0.12.0: f0c419429ef30723ceaf6b42f9b5a2aeb5d2e2d1
-refs/heads/beta: 7f9953b9745dec2d67ed735dff461795bd48863a
+refs/heads/beta: e99b53e1c16b6ab7dcac7ccc841fb9cb9fc75381
 refs/tags/1.0.0-alpha: e42bd6d93a1d3433c486200587f8f9e12590a4d7
 refs/heads/tmp: 938f5d7af401e2d8238522fed4a612943b6e77fd
 refs/tags/1.0.0-alpha.2: 4c705f6bc559886632d3871b04f58aab093bfa2f

branches/beta/src/librustc_typeck/check/dropck.rs

@@ -14,6 +14,7 @@ use middle::infer;
 use middle::region;
 use middle::subst::{self, Subst};
 use middle::ty::{self, Ty};
+use util::nodemap::FnvHashSet;
 
 use syntax::ast;
 use syntax::codemap::{self, Span};
@@ -268,7 +269,7 @@ pub fn check_safety_of_destructor_if_necessary<'a, 'tcx>(rcx: &mut Rcx<'a, 'tcx>
             rcx: rcx,
             span: span,
             parent_scope: parent_scope,
-            breadcrumbs: vec![]
+            breadcrumbs: FnvHashSet()
         },
         TypeContext::Root,
         typ,
@@ -331,7 +332,7 @@ enum TypeContext {
 struct DropckContext<'a, 'b: 'a, 'tcx: 'b> {
     rcx: &'a mut Rcx<'b, 'tcx>,
     /// types that have already been traversed
-    breadcrumbs: Vec<Ty<'tcx>>,
+    breadcrumbs: FnvHashSet<Ty<'tcx>>,
     /// span for error reporting
     span: Span,
     /// the scope reachable dtorck types must outlive
@@ -358,15 +359,13 @@ fn iterate_over_potentially_unsafe_regions_in_type<'a, 'b, 'tcx>(
 
     let opt_phantom_data_def_id = tcx.lang_items.phantom_data();
 
-    // FIXME(arielb1): don't be O(n^2)
-    if cx.breadcrumbs.contains(&ty) {
+    if !cx.breadcrumbs.insert(ty) {
         debug!("iterate_over_potentially_unsafe_regions_in_type \
                {}ty: {} scope: {:?} - cached",
                (0..depth).map(|_| ' ').collect::<String>(),
                ty, cx.parent_scope);
         return Ok(()); // we already visited this type
     }
-    cx.breadcrumbs.push(ty);
     debug!("iterate_over_potentially_unsafe_regions_in_type \
            {}ty: {} scope: {:?}",
            (0..depth).map(|_| ' ').collect::<String>(),