bless all

54 files changed, 151 insertions, 76 deletions

diff --git a/src/test/compile-fail/specialization/issue-50452.rs b/src/test/compile-fail/specialization/issue-50452.rs
index d9e5280c7e1..958f0eb2668 100644
--- a/src/test/compile-fail/specialization/issue-50452.rs
+++ b/src/test/compile-fail/specialization/issue-50452.rs
@@ -1,6 +1,6 @@
 // compile-fail
-
 #![feature(specialization)]
+//~^ WARN the feature `specialization` is incomplete
 
 pub trait Foo {
     fn foo();
diff --git a/src/test/ui/associated-types/defaults-specialization.stderr b/src/test/ui/associated-types/defaults-specialization.stderr
index d71b8045352..09a8c8f8a88 100644
--- a/src/test/ui/associated-types/defaults-specialization.stderr
+++ b/src/test/ui/associated-types/defaults-specialization.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/defaults-specialization.rs:3:38
    |
 LL | #![feature(associated_type_defaults, specialization)]
diff --git a/src/test/ui/coherence/coherence-inherited-assoc-ty-cycle-err.rs b/src/test/ui/coherence/coherence-inherited-assoc-ty-cycle-err.rs
index 7f0e5472c3c..d74d3a2a523 100644
--- a/src/test/ui/coherence/coherence-inherited-assoc-ty-cycle-err.rs
+++ b/src/test/ui/coherence/coherence-inherited-assoc-ty-cycle-err.rs
@@ -4,6 +4,7 @@
 //
 // No we expect to run into a more user-friendly cycle error instead.
 #![feature(specialization)]
+//~^ WARN the feature `specialization` is incomplete
 
 trait Trait<T> { type Assoc; }
 //~^ ERROR E0391
diff --git a/src/test/ui/coherence/coherence-inherited-assoc-ty-cycle-err.stderr b/src/test/ui/coherence/coherence-inherited-assoc-ty-cycle-err.stderr
index 71f997c54c6..7e140480b77 100644
--- a/src/test/ui/coherence/coherence-inherited-assoc-ty-cycle-err.stderr
+++ b/src/test/ui/coherence/coherence-inherited-assoc-ty-cycle-err.stderr
@@ -1,16 +1,25 @@
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/coherence-inherited-assoc-ty-cycle-err.rs:6:12
+   |
+LL | #![feature(specialization)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
+
 error[E0391]: cycle detected when building specialization graph of trait `Trait`
-  --> $DIR/coherence-inherited-assoc-ty-cycle-err.rs:8:1
+  --> $DIR/coherence-inherited-assoc-ty-cycle-err.rs:9:1
    |
 LL | trait Trait<T> { type Assoc; }
    | ^^^^^^^^^^^^^^
    |
    = note: ...which again requires building specialization graph of trait `Trait`, completing the cycle
 note: cycle used when coherence checking all impls of trait `Trait`
-  --> $DIR/coherence-inherited-assoc-ty-cycle-err.rs:8:1
+  --> $DIR/coherence-inherited-assoc-ty-cycle-err.rs:9:1
    |
 LL | trait Trait<T> { type Assoc; }
    | ^^^^^^^^^^^^^^
 
-error: aborting due to previous error
+error: aborting due to previous error; 1 warning emitted
 
 For more information about this error, try `rustc --explain E0391`.
diff --git a/src/test/ui/error-codes/E0520.rs b/src/test/ui/error-codes/E0520.rs
index b746ca63590..ead78b7ffa2 100644
--- a/src/test/ui/error-codes/E0520.rs
+++ b/src/test/ui/error-codes/E0520.rs
@@ -1,4 +1,5 @@
 #![feature(specialization)]
+//~^ WARN the feature `specialization` is incomplete
 
 trait SpaceLlama {
     fn fly(&self);
diff --git a/src/test/ui/error-codes/E0520.stderr b/src/test/ui/error-codes/E0520.stderr
index 72fc85ab1e7..1041ccee937 100644
--- a/src/test/ui/error-codes/E0520.stderr
+++ b/src/test/ui/error-codes/E0520.stderr
@@ -1,5 +1,14 @@
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/E0520.rs:1:12
+   |
+LL | #![feature(specialization)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
+
 error[E0520]: `fly` specializes an item from a parent `impl`, but that item is not marked `default`
-  --> $DIR/E0520.rs:16:5
+  --> $DIR/E0520.rs:17:5
    |
 LL | / impl<T: Clone> SpaceLlama for T {
 LL | |     fn fly(&self) {}
@@ -11,6 +20,6 @@ LL |       default fn fly(&self) {}
    |
    = note: to specialize, `fly` in the parent `impl` must be marked `default`
 
-error: aborting due to previous error
+error: aborting due to previous error; 1 warning emitted
 
 For more information about this error, try `rustc --explain E0520`.
diff --git a/src/test/ui/issues/issue-35376.rs b/src/test/ui/issues/issue-35376.rs
index eb139ec4d7f..cc35213b93d 100644
--- a/src/test/ui/issues/issue-35376.rs
+++ b/src/test/ui/issues/issue-35376.rs
@@ -1,5 +1,6 @@
 // check-pass
 #![feature(specialization)]
+//~^ WARN the feature `specialization` is incomplete
 
 fn main() {}
 
diff --git a/src/test/ui/issues/issue-35376.stderr b/src/test/ui/issues/issue-35376.stderr
new file mode 100644
index 00000000000..06c31f3bae0
--- /dev/null
+++ b/src/test/ui/issues/issue-35376.stderr
@@ -0,0 +1,11 @@
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/issue-35376.rs:2:12
+   |
+LL | #![feature(specialization)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
+
+warning: 1 warning emitted
+
diff --git a/src/test/ui/issues/issue-38091.rs b/src/test/ui/issues/issue-38091.rs
index 00aa810f830..c1262430502 100644
--- a/src/test/ui/issues/issue-38091.rs
+++ b/src/test/ui/issues/issue-38091.rs
@@ -1,5 +1,6 @@
 // run-pass
 #![feature(specialization)]
+//~^ WARN the feature `specialization` is incomplete
 
 trait Iterate<'a> {
     type Ty: Valid;
diff --git a/src/test/ui/issues/issue-38091.stderr b/src/test/ui/issues/issue-38091.stderr
new file mode 100644
index 00000000000..a9855445f66
--- /dev/null
+++ b/src/test/ui/issues/issue-38091.stderr
@@ -0,0 +1,11 @@
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/issue-38091.rs:2:12
+   |
+LL | #![feature(specialization)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
+
+warning: 1 warning emitted
+
diff --git a/src/test/ui/issues/issue-55380.rs b/src/test/ui/issues/issue-55380.rs
index 862218e2192..f7cb296d3b8 100644
--- a/src/test/ui/issues/issue-55380.rs
+++ b/src/test/ui/issues/issue-55380.rs
@@ -1,6 +1,6 @@
 // run-pass
-
 #![feature(specialization)]
+//~^ WARN the feature `specialization` is incomplete
 
 pub trait Foo {
     fn abc() -> u32;
diff --git a/src/test/ui/issues/issue-55380.stderr b/src/test/ui/issues/issue-55380.stderr
new file mode 100644
index 00000000000..451beebd106
--- /dev/null
+++ b/src/test/ui/issues/issue-55380.stderr
@@ -0,0 +1,11 @@
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/issue-55380.rs:2:12
+   |
+LL | #![feature(specialization)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
+
+warning: 1 warning emitted
+
diff --git a/src/test/ui/overlap-doesnt-conflict-with-specialization.stderr b/src/test/ui/overlap-doesnt-conflict-with-specialization.stderr
index d49e97bc09c..16df31ba2a8 100644
--- a/src/test/ui/overlap-doesnt-conflict-with-specialization.stderr
+++ b/src/test/ui/overlap-doesnt-conflict-with-specialization.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/overlap-doesnt-conflict-with-specialization.rs:4:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/parser/assoc-static-semantic-fail.rs b/src/test/ui/parser/assoc-static-semantic-fail.rs
index 215a2921315..a8759d2090d 100644
--- a/src/test/ui/parser/assoc-static-semantic-fail.rs
+++ b/src/test/ui/parser/assoc-static-semantic-fail.rs
@@ -1,6 +1,7 @@
 // Semantically, we do not allow e.g., `static X: u8 = 0;` as an associated item.
 
 #![feature(specialization)]
+//~^ WARN the feature `specialization` is incomplete
 
 fn main() {}
 
diff --git a/src/test/ui/parser/assoc-static-semantic-fail.stderr b/src/test/ui/parser/assoc-static-semantic-fail.stderr
index 612297c9cd8..bc3054c3e30 100644
--- a/src/test/ui/parser/assoc-static-semantic-fail.stderr
+++ b/src/test/ui/parser/assoc-static-semantic-fail.stderr
@@ -1,17 +1,17 @@
 error: associated `static` items are not allowed
-  --> $DIR/assoc-static-semantic-fail.rs:9:5
+  --> $DIR/assoc-static-semantic-fail.rs:10:5
    |
 LL |     static IA: u8 = 0;
    |     ^^^^^^^^^^^^^^^^^^
 
 error: associated `static` items are not allowed
-  --> $DIR/assoc-static-semantic-fail.rs:11:5
+  --> $DIR/assoc-static-semantic-fail.rs:12:5
    |
 LL |     static IB: u8;
    |     ^^^^^^^^^^^^^^
 
 error: a static item cannot be `default`
-  --> $DIR/assoc-static-semantic-fail.rs:14:5
+  --> $DIR/assoc-static-semantic-fail.rs:15:5
    |
 LL |     default static IC: u8 = 0;
    |     ^^^^^^^ `default` because of this
@@ -19,13 +19,13 @@ LL |     default static IC: u8 = 0;
    = note: only associated `fn`, `const`, and `type` items can be `default`
 
 error: associated `static` items are not allowed
-  --> $DIR/assoc-static-semantic-fail.rs:14:5
+  --> $DIR/assoc-static-semantic-fail.rs:15:5
    |
 LL |     default static IC: u8 = 0;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: a static item cannot be `default`
-  --> $DIR/assoc-static-semantic-fail.rs:17:16
+  --> $DIR/assoc-static-semantic-fail.rs:18:16
    |
 LL |     pub(crate) default static ID: u8;
    |                ^^^^^^^ `default` because of this
@@ -33,25 +33,25 @@ LL |     pub(crate) default static ID: u8;
    = note: only associated `fn`, `const`, and `type` items can be `default`
 
 error: associated `static` items are not allowed
-  --> $DIR/assoc-static-semantic-fail.rs:17:5
+  --> $DIR/assoc-static-semantic-fail.rs:18:5
    |
 LL |     pub(crate) default static ID: u8;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: associated `static` items are not allowed
-  --> $DIR/assoc-static-semantic-fail.rs:24:5
+  --> $DIR/assoc-static-semantic-fail.rs:25:5
    |
 LL |     static TA: u8 = 0;
    |     ^^^^^^^^^^^^^^^^^^
 
 error: associated `static` items are not allowed
-  --> $DIR/assoc-static-semantic-fail.rs:26:5
+  --> $DIR/assoc-static-semantic-fail.rs:27:5
    |
 LL |     static TB: u8;
    |     ^^^^^^^^^^^^^^
 
 error: a static item cannot be `default`
-  --> $DIR/assoc-static-semantic-fail.rs:28:5
+  --> $DIR/assoc-static-semantic-fail.rs:29:5
    |
 LL |     default static TC: u8 = 0;
    |     ^^^^^^^ `default` because of this
@@ -59,13 +59,13 @@ LL |     default static TC: u8 = 0;
    = note: only associated `fn`, `const`, and `type` items can be `default`
 
 error: associated `static` items are not allowed
-  --> $DIR/assoc-static-semantic-fail.rs:28:5
+  --> $DIR/assoc-static-semantic-fail.rs:29:5
    |
 LL |     default static TC: u8 = 0;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: a static item cannot be `default`
-  --> $DIR/assoc-static-semantic-fail.rs:31:16
+  --> $DIR/assoc-static-semantic-fail.rs:32:16
    |
 LL |     pub(crate) default static TD: u8;
    |                ^^^^^^^ `default` because of this
@@ -73,25 +73,25 @@ LL |     pub(crate) default static TD: u8;
    = note: only associated `fn`, `const`, and `type` items can be `default`
 
 error: associated `static` items are not allowed
-  --> $DIR/assoc-static-semantic-fail.rs:31:5
+  --> $DIR/assoc-static-semantic-fail.rs:32:5
    |
 LL |     pub(crate) default static TD: u8;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: associated `static` items are not allowed
-  --> $DIR/assoc-static-semantic-fail.rs:38:5
+  --> $DIR/assoc-static-semantic-fail.rs:39:5
    |
 LL |     static TA: u8 = 0;
    |     ^^^^^^^^^^^^^^^^^^
 
 error: associated `static` items are not allowed
-  --> $DIR/assoc-static-semantic-fail.rs:40:5
+  --> $DIR/assoc-static-semantic-fail.rs:41:5
    |
 LL |     static TB: u8;
    |     ^^^^^^^^^^^^^^
 
 error: a static item cannot be `default`
-  --> $DIR/assoc-static-semantic-fail.rs:43:5
+  --> $DIR/assoc-static-semantic-fail.rs:44:5
    |
 LL |     default static TC: u8 = 0;
    |     ^^^^^^^ `default` because of this
@@ -99,13 +99,13 @@ LL |     default static TC: u8 = 0;
    = note: only associated `fn`, `const`, and `type` items can be `default`
 
 error: associated `static` items are not allowed
-  --> $DIR/assoc-static-semantic-fail.rs:43:5
+  --> $DIR/assoc-static-semantic-fail.rs:44:5
    |
 LL |     default static TC: u8 = 0;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: a static item cannot be `default`
-  --> $DIR/assoc-static-semantic-fail.rs:46:9
+  --> $DIR/assoc-static-semantic-fail.rs:47:9
    |
 LL |     pub default static TD: u8;
    |         ^^^^^^^ `default` because of this
@@ -113,13 +113,13 @@ LL |     pub default static TD: u8;
    = note: only associated `fn`, `const`, and `type` items can be `default`
 
 error: associated `static` items are not allowed
-  --> $DIR/assoc-static-semantic-fail.rs:46:5
+  --> $DIR/assoc-static-semantic-fail.rs:47:5
    |
 LL |     pub default static TD: u8;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: associated constant in `impl` without body
-  --> $DIR/assoc-static-semantic-fail.rs:11:5
+  --> $DIR/assoc-static-semantic-fail.rs:12:5
    |
 LL |     static IB: u8;
    |     ^^^^^^^^^^^^^-
@@ -127,7 +127,7 @@ LL |     static IB: u8;
    |                  help: provide a definition for the constant: `= <expr>;`
 
 error: associated constant in `impl` without body
-  --> $DIR/assoc-static-semantic-fail.rs:17:5
+  --> $DIR/assoc-static-semantic-fail.rs:18:5
    |
 LL |     pub(crate) default static ID: u8;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
@@ -135,13 +135,13 @@ LL |     pub(crate) default static ID: u8;
    |                                     help: provide a definition for the constant: `= <expr>;`
 
 error[E0449]: unnecessary visibility qualifier
-  --> $DIR/assoc-static-semantic-fail.rs:31:5
+  --> $DIR/assoc-static-semantic-fail.rs:32:5
    |
 LL |     pub(crate) default static TD: u8;
    |     ^^^^^^^^^^
 
 error: associated constant in `impl` without body
-  --> $DIR/assoc-static-semantic-fail.rs:40:5
+  --> $DIR/assoc-static-semantic-fail.rs:41:5
    |
 LL |     static TB: u8;
    |     ^^^^^^^^^^^^^-
@@ -149,7 +149,7 @@ LL |     static TB: u8;
    |                  help: provide a definition for the constant: `= <expr>;`
 
 error: associated constant in `impl` without body
-  --> $DIR/assoc-static-semantic-fail.rs:46:5
+  --> $DIR/assoc-static-semantic-fail.rs:47:5
    |
 LL |     pub default static TD: u8;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^-
@@ -157,11 +157,20 @@ LL |     pub default static TD: u8;
    |                              help: provide a definition for the constant: `= <expr>;`
 
 error[E0449]: unnecessary visibility qualifier
-  --> $DIR/assoc-static-semantic-fail.rs:46:5
+  --> $DIR/assoc-static-semantic-fail.rs:47:5
    |
 LL |     pub default static TD: u8;
    |     ^^^ `pub` not permitted here because it's implied
 
-error: aborting due to 24 previous errors
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/assoc-static-semantic-fail.rs:3:12
+   |
+LL | #![feature(specialization)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
+
+error: aborting due to 24 previous errors; 1 warning emitted
 
 For more information about this error, try `rustc --explain E0449`.
diff --git a/src/test/ui/parser/default.rs b/src/test/ui/parser/default.rs
index 64ba4b55311..52338c1f13a 100644
--- a/src/test/ui/parser/default.rs
+++ b/src/test/ui/parser/default.rs
@@ -1,6 +1,7 @@
 // Test successful and unsuccessful parsing of the `default` contextual keyword
 
 #![feature(specialization)]
+//~^ WARN the feature `specialization` is incomplete
 
 trait Foo {
     fn foo<T: Default>() -> T;
diff --git a/src/test/ui/parser/default.stderr b/src/test/ui/parser/default.stderr
index 15c49e8b627..dea35666f37 100644
--- a/src/test/ui/parser/default.stderr
+++ b/src/test/ui/parser/default.stderr
@@ -1,5 +1,5 @@
 error: `default` is not followed by an item
-  --> $DIR/default.rs:22:5
+  --> $DIR/default.rs:23:5
    |
 LL |     default pub fn foo<T: Default>() -> T { T::default() }
    |     ^^^^^^^ the `default` qualifier
@@ -7,7 +7,7 @@ LL |     default pub fn foo<T: Default>() -> T { T::default() }
    = note: only `fn`, `const`, `type`, or `impl` items may be prefixed by `default`
 
 error: non-item in item list
-  --> $DIR/default.rs:22:13
+  --> $DIR/default.rs:23:13
    |
 LL | impl Foo for u32 {
    |                  - item list starts here
@@ -18,13 +18,22 @@ LL | }
    | - item list ends here
 
 error[E0449]: unnecessary visibility qualifier
-  --> $DIR/default.rs:16:5
+  --> $DIR/default.rs:17:5
    |
 LL |     pub default fn foo<T: Default>() -> T {
    |     ^^^ `pub` not permitted here because it's implied
 
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/default.rs:3:12
+   |
+LL | #![feature(specialization)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
+
 error[E0046]: not all trait items implemented, missing: `foo`
-  --> $DIR/default.rs:21:1
+  --> $DIR/default.rs:22:1
    |
 LL |     fn foo<T: Default>() -> T;
    |     -------------------------- `foo` from trait
@@ -32,7 +41,7 @@ LL |     fn foo<T: Default>() -> T;
 LL | impl Foo for u32 {
    | ^^^^^^^^^^^^^^^^ missing `foo` in implementation
 
-error: aborting due to 4 previous errors
+error: aborting due to 4 previous errors; 1 warning emitted
 
 Some errors have detailed explanations: E0046, E0449.
 For more information about an error, try `rustc --explain E0046`.
diff --git a/src/test/ui/specialization/assoc-ty-graph-cycle.stderr b/src/test/ui/specialization/assoc-ty-graph-cycle.stderr
index a7bd37e8259..250f48f8e59 100644
--- a/src/test/ui/specialization/assoc-ty-graph-cycle.stderr
+++ b/src/test/ui/specialization/assoc-ty-graph-cycle.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/assoc-ty-graph-cycle.rs:5:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/cross-crate-defaults.stderr b/src/test/ui/specialization/cross-crate-defaults.stderr
index 6ab4db3e7e1..f18bc99d739 100644
--- a/src/test/ui/specialization/cross-crate-defaults.stderr
+++ b/src/test/ui/specialization/cross-crate-defaults.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/cross-crate-defaults.rs:5:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/defaultimpl/allowed-cross-crate.stderr b/src/test/ui/specialization/defaultimpl/allowed-cross-crate.stderr
index 0966de8394a..1b50329719d 100644
--- a/src/test/ui/specialization/defaultimpl/allowed-cross-crate.stderr
+++ b/src/test/ui/specialization/defaultimpl/allowed-cross-crate.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/allowed-cross-crate.rs:8:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/defaultimpl/out-of-order.stderr b/src/test/ui/specialization/defaultimpl/out-of-order.stderr
index 2901272b39b..deae021a891 100644
--- a/src/test/ui/specialization/defaultimpl/out-of-order.stderr
+++ b/src/test/ui/specialization/defaultimpl/out-of-order.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/out-of-order.rs:5:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/defaultimpl/overlap-projection.stderr b/src/test/ui/specialization/defaultimpl/overlap-projection.stderr
index 245300923cd..46899ca9954 100644
--- a/src/test/ui/specialization/defaultimpl/overlap-projection.stderr
+++ b/src/test/ui/specialization/defaultimpl/overlap-projection.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/overlap-projection.rs:7:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/defaultimpl/projection.stderr b/src/test/ui/specialization/defaultimpl/projection.stderr
index 0fd5ba0e03d..8629c6c52d4 100644
--- a/src/test/ui/specialization/defaultimpl/projection.stderr
+++ b/src/test/ui/specialization/defaultimpl/projection.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/projection.rs:4:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/defaultimpl/specialization-no-default.stderr b/src/test/ui/specialization/defaultimpl/specialization-no-default.stderr
index 6cbaae7edbc..7958eddbeba 100644
--- a/src/test/ui/specialization/defaultimpl/specialization-no-default.stderr
+++ b/src/test/ui/specialization/defaultimpl/specialization-no-default.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-no-default.rs:1:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/defaultimpl/specialization-wfcheck.stderr b/src/test/ui/specialization/defaultimpl/specialization-wfcheck.stderr
index 5eeb07f992e..d45825651a8 100644
--- a/src/test/ui/specialization/defaultimpl/specialization-wfcheck.stderr
+++ b/src/test/ui/specialization/defaultimpl/specialization-wfcheck.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-wfcheck.rs:3:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/defaultimpl/validation.stderr b/src/test/ui/specialization/defaultimpl/validation.stderr
index 0752614674d..2449849725f 100644
--- a/src/test/ui/specialization/defaultimpl/validation.stderr
+++ b/src/test/ui/specialization/defaultimpl/validation.stderr
@@ -8,7 +8,7 @@ LL | default impl S {}
    |
    = note: only trait implementations may be annotated with `default`
 
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/validation.rs:2:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/issue-36804.stderr b/src/test/ui/specialization/issue-36804.stderr
index 9be2888592c..744d8820424 100644
--- a/src/test/ui/specialization/issue-36804.stderr
+++ b/src/test/ui/specialization/issue-36804.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/issue-36804.rs:2:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/issue-39448.stderr b/src/test/ui/specialization/issue-39448.stderr
index 886b2e1e8d4..f3bb69b8f71 100644
--- a/src/test/ui/specialization/issue-39448.stderr
+++ b/src/test/ui/specialization/issue-39448.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/issue-39448.rs:1:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/issue-39618.stderr b/src/test/ui/specialization/issue-39618.stderr
index 1712b4afbca..d40d17d8f71 100644
--- a/src/test/ui/specialization/issue-39618.stderr
+++ b/src/test/ui/specialization/issue-39618.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/issue-39618.rs:7:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/issue-50452.stderr b/src/test/ui/specialization/issue-50452.stderr
index efae48d0ed4..c01817e0b27 100644
--- a/src/test/ui/specialization/issue-50452.stderr
+++ b/src/test/ui/specialization/issue-50452.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/issue-50452.rs:3:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/issue-52050.stderr b/src/test/ui/specialization/issue-52050.stderr
index bf95b0a3faa..a7564ced055 100644
--- a/src/test/ui/specialization/issue-52050.stderr
+++ b/src/test/ui/specialization/issue-52050.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/issue-52050.rs:1:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/issue-63716-parse-async.stderr b/src/test/ui/specialization/issue-63716-parse-async.stderr
index 4c2bf69590e..43620e1ba51 100644
--- a/src/test/ui/specialization/issue-63716-parse-async.stderr
+++ b/src/test/ui/specialization/issue-63716-parse-async.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/issue-63716-parse-async.rs:7:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/issue-70442.stderr b/src/test/ui/specialization/issue-70442.stderr
index 1f846cc449d..f71e4c7dd1c 100644
--- a/src/test/ui/specialization/issue-70442.stderr
+++ b/src/test/ui/specialization/issue-70442.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/issue-70442.rs:1:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/non-defaulted-item-fail.stderr b/src/test/ui/specialization/non-defaulted-item-fail.stderr
index 084266205b6..eae045b92c0 100644
--- a/src/test/ui/specialization/non-defaulted-item-fail.stderr
+++ b/src/test/ui/specialization/non-defaulted-item-fail.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/non-defaulted-item-fail.rs:1:12
    |
 LL | #![feature(specialization, associated_type_defaults)]
diff --git a/src/test/ui/specialization/specialization-allowed-cross-crate.stderr b/src/test/ui/specialization/specialization-allowed-cross-crate.stderr
index 734e90baed1..7d087545725 100644
--- a/src/test/ui/specialization/specialization-allowed-cross-crate.stderr
+++ b/src/test/ui/specialization/specialization-allowed-cross-crate.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-allowed-cross-crate.rs:8:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-assoc-fns.stderr b/src/test/ui/specialization/specialization-assoc-fns.stderr
index 1ad3ea8ffd3..b12738604ea 100644
--- a/src/test/ui/specialization/specialization-assoc-fns.stderr
+++ b/src/test/ui/specialization/specialization-assoc-fns.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-assoc-fns.rs:5:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-basics.stderr b/src/test/ui/specialization/specialization-basics.stderr
index 37b586f4df7..ad00cd81df1 100644
--- a/src/test/ui/specialization/specialization-basics.stderr
+++ b/src/test/ui/specialization/specialization-basics.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-basics.rs:3:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-cross-crate.stderr b/src/test/ui/specialization/specialization-cross-crate.stderr
index fd853db4323..7481eed796d 100644
--- a/src/test/ui/specialization/specialization-cross-crate.stderr
+++ b/src/test/ui/specialization/specialization-cross-crate.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-cross-crate.rs:5:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-default-methods.stderr b/src/test/ui/specialization/specialization-default-methods.stderr
index 4e069e858fa..4fa19adad06 100644
--- a/src/test/ui/specialization/specialization-default-methods.stderr
+++ b/src/test/ui/specialization/specialization-default-methods.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-default-methods.rs:3:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-default-projection.stderr b/src/test/ui/specialization/specialization-default-projection.stderr
index 695102a1878..456eb6d5ca5 100644
--- a/src/test/ui/specialization/specialization-default-projection.stderr
+++ b/src/test/ui/specialization/specialization-default-projection.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-default-projection.rs:1:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-default-types.stderr b/src/test/ui/specialization/specialization-default-types.stderr
index 7fe2366f781..5e0221f0788 100644
--- a/src/test/ui/specialization/specialization-default-types.stderr
+++ b/src/test/ui/specialization/specialization-default-types.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-default-types.rs:5:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-no-default.stderr b/src/test/ui/specialization/specialization-no-default.stderr
index 0222cba2ba6..bb8b2a6c98e 100644
--- a/src/test/ui/specialization/specialization-no-default.stderr
+++ b/src/test/ui/specialization/specialization-no-default.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-no-default.rs:1:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-on-projection.stderr b/src/test/ui/specialization/specialization-on-projection.stderr
index 173f9eee8f9..d91668d10c5 100644
--- a/src/test/ui/specialization/specialization-on-projection.stderr
+++ b/src/test/ui/specialization/specialization-on-projection.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-on-projection.rs:4:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-out-of-order.stderr b/src/test/ui/specialization/specialization-out-of-order.stderr
index 27d5d851f52..a17f9f11a3f 100644
--- a/src/test/ui/specialization/specialization-out-of-order.stderr
+++ b/src/test/ui/specialization/specialization-out-of-order.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-out-of-order.rs:5:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-overlap-negative.stderr b/src/test/ui/specialization/specialization-overlap-negative.stderr
index a28f961c03c..6141174ba8c 100644
--- a/src/test/ui/specialization/specialization-overlap-negative.stderr
+++ b/src/test/ui/specialization/specialization-overlap-negative.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-overlap-negative.rs:2:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-overlap-projection.stderr b/src/test/ui/specialization/specialization-overlap-projection.stderr
index 10952ede91a..6f1a594bacb 100644
--- a/src/test/ui/specialization/specialization-overlap-projection.stderr
+++ b/src/test/ui/specialization/specialization-overlap-projection.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-overlap-projection.rs:7:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-overlap.stderr b/src/test/ui/specialization/specialization-overlap.stderr
index 7cc865b62ad..cf0f186a183 100644
--- a/src/test/ui/specialization/specialization-overlap.stderr
+++ b/src/test/ui/specialization/specialization-overlap.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-overlap.rs:1:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-polarity.stderr b/src/test/ui/specialization/specialization-polarity.stderr
index 7d269fe3293..c44af22b8e6 100644
--- a/src/test/ui/specialization/specialization-polarity.stderr
+++ b/src/test/ui/specialization/specialization-polarity.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-polarity.rs:5:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-projection-alias.stderr b/src/test/ui/specialization/specialization-projection-alias.stderr
index 385c4e2df91..0c3659a8f7a 100644
--- a/src/test/ui/specialization/specialization-projection-alias.stderr
+++ b/src/test/ui/specialization/specialization-projection-alias.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-projection-alias.rs:5:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-projection.stderr b/src/test/ui/specialization/specialization-projection.stderr
index ef676d2f240..c5c86f5108e 100644
--- a/src/test/ui/specialization/specialization-projection.stderr
+++ b/src/test/ui/specialization/specialization-projection.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-projection.rs:4:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-translate-projections-with-lifetimes.stderr b/src/test/ui/specialization/specialization-translate-projections-with-lifetimes.stderr
index 3fc6f350ba2..6284dd8f3f7 100644
--- a/src/test/ui/specialization/specialization-translate-projections-with-lifetimes.stderr
+++ b/src/test/ui/specialization/specialization-translate-projections-with-lifetimes.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-translate-projections-with-lifetimes.rs:3:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-translate-projections-with-params.stderr b/src/test/ui/specialization/specialization-translate-projections-with-params.stderr
index 58ac70a309c..b17794173c5 100644
--- a/src/test/ui/specialization/specialization-translate-projections-with-params.stderr
+++ b/src/test/ui/specialization/specialization-translate-projections-with-params.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-translate-projections-with-params.rs:7:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/specialization/specialization-translate-projections.stderr b/src/test/ui/specialization/specialization-translate-projections.stderr
index 8d5156d5a99..fbb28e60640 100644
--- a/src/test/ui/specialization/specialization-translate-projections.stderr
+++ b/src/test/ui/specialization/specialization-translate-projections.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/specialization-translate-projections.rs:6:12
    |
 LL | #![feature(specialization)]
diff --git a/src/test/ui/transmute-specialization.stderr b/src/test/ui/transmute-specialization.stderr
index 9158e3142d8..02315051d30 100644
--- a/src/test/ui/transmute-specialization.stderr
+++ b/src/test/ui/transmute-specialization.stderr
@@ -1,4 +1,4 @@
-warning: the feature `specialization` is incomplete and may be unsafe to use and/or cause compiler crashes
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/transmute-specialization.rs:3:12
    |
 LL | #![feature(specialization)]