Remove drop flags from structs and enums implementing Drop.

3 files changed, 17 insertions, 15 deletions

diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index 05a485cefab..d746f8e2114 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -164,10 +164,6 @@ declare_features! (
     // Allows using `box` in patterns; RFC 469
     (active, box_patterns, "1.0.0", Some(29641)),
 
-    // Allows using the unsafe_no_drop_flag attribute (unlikely to
-    // switch to Accepted; see RFC 320)
-    (active, unsafe_no_drop_flag, "1.0.0", None),
-
     // Allows using the unsafe_destructor_blind_to_params attribute;
     // RFC 1238
     (active, dropck_parametricity, "1.3.0", Some(28498)),
@@ -300,7 +296,8 @@ declare_features! (
     (removed, quad_precision_float, "1.0.0", None),
     (removed, struct_inherit, "1.0.0", None),
     (removed, test_removed_feature, "1.0.0", None),
-    (removed, visible_private_types, "1.0.0", None)
+    (removed, visible_private_types, "1.0.0", None),
+    (removed, unsafe_no_drop_flag, "1.0.0", None)
 );
 
 declare_features! (
@@ -565,10 +562,6 @@ pub const KNOWN_ATTRIBUTES: &'static [(&'static str, AttributeType, AttributeGat
                                                         attribute is just used for the Rust test \
                                                         suite",
                                                        cfg_fn!(omit_gdb_pretty_printer_section))),
-    ("unsafe_no_drop_flag", Whitelisted, Gated("unsafe_no_drop_flag",
-                                               "unsafe_no_drop_flag has unstable semantics \
-                                                and may be removed in the future",
-                                               cfg_fn!(unsafe_no_drop_flag))),
     ("unsafe_destructor_blind_to_params",
      Normal,
      Gated("dropck_parametricity",
diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index b4311fc007d..65bc9f34c90 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -26,7 +26,6 @@
 
 #![feature(associated_consts)]
 #![feature(const_fn)]
-#![feature(filling_drop)]
 #![feature(libc)]
 #![feature(rustc_private)]
 #![feature(staged_api)]
diff --git a/src/libsyntax/ptr.rs b/src/libsyntax/ptr.rs
index 9d04cb75daa..c3f8a977a65 100644
--- a/src/libsyntax/ptr.rs
+++ b/src/libsyntax/ptr.rs
@@ -39,7 +39,7 @@
 use std::fmt::{self, Display, Debug};
 use std::iter::FromIterator;
 use std::ops::Deref;
-use std::{ptr, slice, vec};
+use std::{mem, ptr, slice, vec};
 
 use serialize::{Encodable, Decodable, Encoder, Decoder};
 
@@ -74,12 +74,22 @@ impl<T: 'static> P<T> {
     pub fn map<F>(mut self, f: F) -> P<T> where
         F: FnOnce(T) -> T,
     {
+        let p: *mut T = &mut *self.ptr;
+
+        // Leak self in case of panic.
+        // FIXME(eddyb) Use some sort of "free guard" that
+        // only deallocates, without dropping the pointee,
+        // in case the call the `f` below ends in a panic.
+        mem::forget(self);
+
         unsafe {
-            let p = &mut *self.ptr;
-            // FIXME(#5016) this shouldn't need to drop-fill to be safe.
-            ptr::write(p, f(ptr::read_and_drop(p)));
+            ptr::write(p, f(ptr::read(p)));
+
+            // Recreate self from the raw pointer.
+            P {
+                ptr: Box::from_raw(p)
+            }
         }
-        self
     }
 }