Auto merge of rust-lang#1134 - RalfJung:macos-hashmap, r=RalfJung

test macOS hashmap

With rust-lang#1130 landed, this should work now. Thanks @christianpoveda!

Fixes rust-lang#686

tests/run-pass/hashmap.rs

@@ -1,5 +1,8 @@
-use std::collections::{self, HashMap};
-use std::hash::{BuildHasherDefault, BuildHasher};
+// macOS needs FS access for its HashMap:
+// compile-flags: -Zmiri-disable-isolation
+
+use std::collections::HashMap;
+use std::hash::BuildHasher;
 
 fn test_map<S: BuildHasher>(mut map: HashMap<i32, i32, S>) {
     map.insert(0, 0);
@@ -18,14 +21,8 @@ fn test_map<S: BuildHasher>(mut map: HashMap<i32, i32, S>) {
     assert_eq!(map.values().fold(0, |x, y| x+y), num*(num-1)/2);
 
     // TODO: Test Entry API, Iterators, ...
-
 }
 
 fn main() {
-    if cfg!(target_os = "macos") { // TODO: Implement libstd HashMap seeding for macOS (https://github.com/rust-lang/miri/issues/686).
-        // Until then, use a deterministic map.
-        test_map::<BuildHasherDefault<collections::hash_map::DefaultHasher>>(HashMap::default());
-    } else {
-        test_map(HashMap::new());
-    }
+    test_map(HashMap::new());
 }