Add RFC 1238's `unsafe_destructor_blind_to_params` (UGEH) where needed.

I needed it in `RawVec`, `Vec`, and `TypedArena` for `rustc` to
bootstrap; but of course that alone was not sufficient for `make
check`.

Later I added `unsafe_destructor_blind_to_params` to collections, in
particular `LinkedList` and `RawTable` (the backing representation for
`HashMap` and `HashSet`), to get the regression tests exercising
cyclic structure from PR #27185 building.

----

Note that the feature is `dropck_parametricity` (which is not the same
as the attribute's name). We will almost certainly vary our strategy
here in the future, so it makes some sense to have a not-as-ugly name
for the feature gate. (The attribute name was deliberately selected to
be ugly looking.)

1 files changed, 4 insertions, 4 deletions

diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index e364716bdf2..e134e5617dc 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -136,9 +136,9 @@ const KNOWN_FEATURES: &'static [(&'static str, &'static str, Option<u32>, Status
     // switch to Accepted; see RFC 320)
     ("unsafe_no_drop_flag", "1.0.0", None, Active),
 
-    // Allows using the unsafe_destructor_blind_to_params attribute
-    // (Needs an RFC link)
-    ("unsafe_destructor_blind_to_params", "1.3.0", Some(28498), Active),
+    // Allows using the unsafe_destructor_blind_to_params attribute;
+    // RFC 1238
+    ("dropck_parametricity", "1.3.0", Some(28498), Active),
 
     // Allows the use of custom attributes; RFC 572
     ("custom_attribute", "1.0.0", None, Active),
@@ -345,7 +345,7 @@ pub const KNOWN_ATTRIBUTES: &'static [(&'static str, AttributeType, AttributeGat
                                                 and may be removed in the future")),
     ("unsafe_destructor_blind_to_params",
      Normal,
-     Gated("unsafe_destructor_blind_to_params",
+     Gated("dropck_parametricity",
            "unsafe_destructor_blind_to_params has unstable semantics \
             and may be removed in the future")),
     ("unwind", Whitelisted, Gated("unwind_attributes", "#[unwind] is experimental")),