rollup merge of #23288: alexcrichton/issue-19470

This is a deprecated attribute that is slated for removal, and it also affects
all implementors of the trait. This commit removes the attribute and fixes up
implementors accordingly. The primary implementation which was lost was the
ability to compare `&[T]` and `Vec<T>` (in that order).

This change also modifies the `assert_eq!` macro to not consider both directions
of equality, only the one given in the left/right forms to the macro. This
modification is motivated due to the fact that `&[T] == Vec<T>` no longer
compiles, causing hundreds of errors in unit tests in the standard library (and
likely throughout the community as well).

Closes #19470
[breaking-change]

2 files changed, 3 insertions, 20 deletions

diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index 4a977fe02c4..f88381fb36f 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -102,9 +102,6 @@ const KNOWN_FEATURES: &'static [(&'static str, &'static str, Status)] = &[
     // A way to temporarily opt out of opt in copy. This will *never* be accepted.
     ("opt_out_copy", "1.0.0", Removed),
 
-    // A way to temporarily opt out of the new orphan rules. This will *never* be accepted.
-    ("old_orphan_check", "1.0.0", Deprecated),
-
     // OIBIT specific features
     ("optin_builtin_traits", "1.0.0", Active),
 
@@ -273,9 +270,6 @@ pub const KNOWN_ATTRIBUTES: &'static [(&'static str, AttributeType)] = &[
     ("stable", Whitelisted),
     ("unstable", Whitelisted),
 
-    // FIXME: #19470 this shouldn't be needed forever
-    ("old_orphan_check", Whitelisted),
-
     ("rustc_paren_sugar", Gated("unboxed_closures",
                                 "unboxed_closures are still evolving")),
     ("rustc_reflect_like", Gated("reflect",
@@ -323,7 +317,6 @@ pub struct Features {
     pub allow_trace_macros: bool,
     pub allow_internal_unstable: bool,
     pub allow_custom_derive: bool,
-    pub old_orphan_check: bool,
     pub simd_ffi: bool,
     pub unmarked_api: bool,
     /// spans of #![feature] attrs for stable language features. for error reporting
@@ -345,7 +338,6 @@ impl Features {
             allow_trace_macros: false,
             allow_internal_unstable: false,
             allow_custom_derive: false,
-            old_orphan_check: false,
             simd_ffi: false,
             unmarked_api: false,
             declared_stable_lang_features: Vec::new(),
@@ -569,14 +561,6 @@ impl<'a, 'v> Visitor<'v> for PostExpansionVisitor<'a> {
                     },
                     _ => {}
                 }
-
-                if attr::contains_name(&i.attrs[..],
-                                       "old_orphan_check") {
-                    self.gate_feature(
-                        "old_orphan_check",
-                        i.span,
-                        "the new orphan check rules will eventually be strictly enforced");
-                }
             }
 
             _ => {}
@@ -726,7 +710,6 @@ fn check_crate_inner<F>(cm: &CodeMap, span_handler: &SpanHandler,
         allow_trace_macros: cx.has_feature("trace_macros"),
         allow_internal_unstable: cx.has_feature("allow_internal_unstable"),
         allow_custom_derive: cx.has_feature("custom_derive"),
-        old_orphan_check: cx.has_feature("old_orphan_check"),
         simd_ffi: cx.has_feature("simd_ffi"),
         unmarked_api: cx.has_feature("unmarked_api"),
         declared_stable_lang_features: accepted_features,
diff --git a/src/libsyntax/util/small_vector.rs b/src/libsyntax/util/small_vector.rs
index 5bd6591cfb0..1649934f4b1 100644
--- a/src/libsyntax/util/small_vector.rs
+++ b/src/libsyntax/util/small_vector.rs
@@ -226,13 +226,13 @@ mod test {
     fn test_move_iter() {
         let v = SmallVector::zero();
         let v: Vec<isize> = v.into_iter().collect();
-        assert_eq!(Vec::new(), v);
+        assert_eq!(v, Vec::new());
 
         let v = SmallVector::one(1);
-        assert_eq!([1], v.into_iter().collect::<Vec<_>>());
+        assert_eq!(v.into_iter().collect::<Vec<_>>(), [1]);
 
         let v = SmallVector::many(vec![1, 2, 3]);
-        assert_eq!([1, 2, 3], v.into_iter().collect::<Vec<_>>());
+        assert_eq!(v.into_iter().collect::<Vec<_>>(), [1, 2, 3]);
     }
 
     #[test]