diff --git a/src/librustc_metadata/native_libs.rs b/src/librustc_metadata/native_libs.rs
index 66971bb6f8b1..66d676b7747d 100644
--- a/src/librustc_metadata/native_libs.rs
+++ b/src/librustc_metadata/native_libs.rs
@@ -159,7 +159,7 @@ impl Collector<'tcx> {
                                            sym::link_cfg,
                                            span.unwrap(),
                                            GateIssue::Language,
-                                           "is feature gated");
+                                           "is unstable");
         }
         if lib.kind == cstore::NativeStaticNobundle &&
            !self.tcx.features().static_nobundle {
@@ -167,7 +167,7 @@ impl Collector<'tcx> {
                                            sym::static_nobundle,
                                            span.unwrap_or_else(|| syntax_pos::DUMMY_SP),
                                            GateIssue::Language,
-                                           "kind=\"static-nobundle\" is feature gated");
+                                           "kind=\"static-nobundle\" is unstable");
         }
         self.libs.push(lib);
     }
diff --git a/src/test/ui/attributes/obsolete-attr.rs b/src/test/ui/attributes/obsolete-attr.rs
index 8759344e6f82..cf6dd338552b 100644
--- a/src/test/ui/attributes/obsolete-attr.rs
+++ b/src/test/ui/attributes/obsolete-attr.rs
@@ -1,4 +1,4 @@
-// Obsolete attributes fall back to feature gated custom attributes.
+// Obsolete attributes fall back to unstable custom attributes.
 
 #[ab_isize="stdcall"] extern {}
 //~^ ERROR cannot find attribute macro `ab_isize` in this scope
diff --git a/src/test/ui/attributes/unknown-attr.rs b/src/test/ui/attributes/unknown-attr.rs
index 140a1fc3f93e..544a6e2a7e78 100644
--- a/src/test/ui/attributes/unknown-attr.rs
+++ b/src/test/ui/attributes/unknown-attr.rs
@@ -1,4 +1,4 @@
-// Unknown attributes fall back to feature gated custom attributes.
+// Unknown attributes fall back to unstable custom attributes.
 
 #![feature(custom_inner_attributes)]
 
diff --git a/src/test/ui/feature-gate/feature-gate-static-nobundle-2.rs b/src/test/ui/feature-gate/feature-gate-static-nobundle-2.rs
index 92844f9306d2..b6c8648a7d03 100644
--- a/src/test/ui/feature-gate/feature-gate-static-nobundle-2.rs
+++ b/src/test/ui/feature-gate/feature-gate-static-nobundle-2.rs
@@ -1,4 +1,4 @@
-//~ ERROR kind="static-nobundle" is feature gated
+//~ ERROR kind="static-nobundle" is unstable
 // Test the behavior of rustc when non-existent library is statically linked
 
 // compile-flags: -l static-nobundle=nonexistent
diff --git a/src/test/ui/feature-gate/feature-gate-static-nobundle-2.stderr b/src/test/ui/feature-gate/feature-gate-static-nobundle-2.stderr
index 059559dd9283..cfff4c36a6d7 100644
--- a/src/test/ui/feature-gate/feature-gate-static-nobundle-2.stderr
+++ b/src/test/ui/feature-gate/feature-gate-static-nobundle-2.stderr
@@ -1,4 +1,4 @@
-error[E0658]: kind="static-nobundle" is feature gated
+error[E0658]: kind="static-nobundle" is unstable
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/37403
    = help: add `#![feature(static_nobundle)]` to the crate attributes to enable
diff --git a/src/test/ui/feature-gates/feature-gate-is_sorted.rs b/src/test/ui/feature-gates/feature-gate-is_sorted.rs
index 078ecc577610..359ed835bcbb 100644
--- a/src/test/ui/feature-gates/feature-gate-is_sorted.rs
+++ b/src/test/ui/feature-gates/feature-gate-is_sorted.rs
@@ -1,11 +1,11 @@
 fn main() {
-    // Assert `Iterator` methods are feature gated
+    // Assert `Iterator` methods are unstable
     assert!([1, 2, 2, 9].iter().is_sorted());
     //~^ ERROR: use of unstable library feature 'is_sorted': new API
     assert!(![-2i32, -1, 0, 3].iter().is_sorted_by_key(|n| n.abs()));
     //~^ ERROR: use of unstable library feature 'is_sorted': new API
 
-    // Assert `[T]` methods are feature gated
+    // Assert `[T]` methods are unstable
     assert!([1, 2, 2, 9].is_sorted());
     //~^ ERROR: use of unstable library feature 'is_sorted': new API
     assert!(![-2i32, -1, 0, 3].is_sorted_by_key(|n| n.abs()));
diff --git a/src/test/ui/feature-gates/feature-gate-link_cfg.rs b/src/test/ui/feature-gates/feature-gate-link_cfg.rs
index 1905346e2b5d..27ec2e98eb68 100644
--- a/src/test/ui/feature-gates/feature-gate-link_cfg.rs
+++ b/src/test/ui/feature-gates/feature-gate-link_cfg.rs
@@ -1,5 +1,5 @@
 #[link(name = "foo", cfg(foo))]
-//~^ ERROR: is feature gated
+//~^ ERROR: is unstable
 extern {}
 
 fn main() {}
diff --git a/src/test/ui/feature-gates/feature-gate-link_cfg.stderr b/src/test/ui/feature-gates/feature-gate-link_cfg.stderr
index 58aa4ed7497c..f6c506154643 100644
--- a/src/test/ui/feature-gates/feature-gate-link_cfg.stderr
+++ b/src/test/ui/feature-gates/feature-gate-link_cfg.stderr
@@ -1,4 +1,4 @@
-error[E0658]: is feature gated
+error[E0658]: is unstable
   --> $DIR/feature-gate-link_cfg.rs:1:1
    |
 LL | #[link(name = "foo", cfg(foo))]
diff --git a/src/test/ui/feature-gates/feature-gate-static-nobundle.rs b/src/test/ui/feature-gates/feature-gate-static-nobundle.rs
index 1ce6c54aa4dc..644b1f964a05 100644
--- a/src/test/ui/feature-gates/feature-gate-static-nobundle.rs
+++ b/src/test/ui/feature-gates/feature-gate-static-nobundle.rs
@@ -1,5 +1,5 @@
 #[link(name="foo", kind="static-nobundle")]
-//~^ ERROR: kind="static-nobundle" is feature gated
+//~^ ERROR: kind="static-nobundle" is unstable
 extern {}
 
 fn main() {}
diff --git a/src/test/ui/feature-gates/feature-gate-static-nobundle.stderr b/src/test/ui/feature-gates/feature-gate-static-nobundle.stderr
index f2e29cf0678a..cc0d426d6cf9 100644
--- a/src/test/ui/feature-gates/feature-gate-static-nobundle.stderr
+++ b/src/test/ui/feature-gates/feature-gate-static-nobundle.stderr
@@ -1,4 +1,4 @@
-error[E0658]: kind="static-nobundle" is feature gated
+error[E0658]: kind="static-nobundle" is unstable
   --> $DIR/feature-gate-static-nobundle.rs:1:1
    |
 LL | #[link(name="foo", kind="static-nobundle")]
diff --git a/src/test/ui/feature-gates/feature-gate-type_ascription.rs b/src/test/ui/feature-gates/feature-gate-type_ascription.rs
index e42e34055068..7a597157300e 100644
--- a/src/test/ui/feature-gates/feature-gate-type_ascription.rs
+++ b/src/test/ui/feature-gates/feature-gate-type_ascription.rs
@@ -1,4 +1,4 @@
-// Type ascription is feature gated
+// Type ascription is unstable
 
 fn main() {
     let a = 10: u8; //~ ERROR type ascription is experimental
diff --git a/src/test/ui/proc-macro/resolve-error.rs b/src/test/ui/proc-macro/resolve-error.rs
index 0a7861aba6eb..088f39c6665f 100644
--- a/src/test/ui/proc-macro/resolve-error.rs
+++ b/src/test/ui/proc-macro/resolve-error.rs
@@ -23,11 +23,11 @@ macro_rules! attr_proc_mac {
 //~^ ERROR cannot find
 struct Foo;
 
-// Interpreted as a feature gated custom attribute
+// Interpreted as an unstable custom attribute
 #[attr_proc_macra] //~ ERROR cannot find attribute macro `attr_proc_macra` in this scope
 struct Bar;
 
-// Interpreted as a feature gated custom attribute
+// Interpreted as an unstable custom attribute
 #[FooWithLongNan] //~ ERROR cannot find attribute macro `FooWithLongNan` in this scope
 struct Asdf;
 
diff --git a/src/test/ui/tool-attributes/tool-attributes-misplaced-1.rs b/src/test/ui/tool-attributes/tool-attributes-misplaced-1.rs
index 8c62b34bd9ea..c07da4345f7d 100644
--- a/src/test/ui/tool-attributes/tool-attributes-misplaced-1.rs
+++ b/src/test/ui/tool-attributes/tool-attributes-misplaced-1.rs
@@ -4,7 +4,7 @@ type B = rustfmt::skip; //~ ERROR expected type, found tool attribute `rustfmt::
 #[derive(rustfmt)] //~ ERROR cannot find derive macro `rustfmt` in this scope
 struct S;
 
-// Interpreted as a feature gated custom attribute
+// Interpreted as an unstable custom attribute
 #[rustfmt] //~ ERROR cannot find attribute macro `rustfmt` in this scope
 fn check() {}