Rollup merge of #132544 - dianne:unstable-library-feature-backticks, r=compiler-errors

Use backticks instead of single quotes for library feature names in diagnostics

This PR changes the text of library feature errors for using unstable or body-unstable items. Displaying library feature names in backticks is consistent with other diagnostics (e.g. those from `rustc_passes`) and with the `reason`s on unstable attributes in the library. Additionally, this simplifies diagnostics when supporting multiple unstable attributes on items (see #131824) since `DiagSymbolList` also displays symbols using backticks.

25 files changed, 110 insertions, 110 deletions

diff --git a/tests/ui/stability-attribute/accidental-stable-in-unstable.rs b/tests/ui/stability-attribute/accidental-stable-in-unstable.rs
index f8bbe90cfc5..86a9d2066eb 100644
--- a/tests/ui/stability-attribute/accidental-stable-in-unstable.rs
+++ b/tests/ui/stability-attribute/accidental-stable-in-unstable.rs
@@ -3,7 +3,7 @@ extern crate core;
 
 // Known accidental stabilizations with no known users, slated for un-stabilization
 // fully stable @ core::char::UNICODE_VERSION
-use core::unicode::UNICODE_VERSION; //~ ERROR use of unstable library feature 'unicode_internals'
+use core::unicode::UNICODE_VERSION; //~ ERROR use of unstable library feature `unicode_internals`
 
 // Known accidental stabilizations with known users
 // fully stable @ core::mem::transmute
diff --git a/tests/ui/stability-attribute/accidental-stable-in-unstable.stderr b/tests/ui/stability-attribute/accidental-stable-in-unstable.stderr
index 4abf8243d2f..9943e6d7ac6 100644
--- a/tests/ui/stability-attribute/accidental-stable-in-unstable.stderr
+++ b/tests/ui/stability-attribute/accidental-stable-in-unstable.stderr
@@ -1,4 +1,4 @@
-error[E0658]: use of unstable library feature 'unicode_internals'
+error[E0658]: use of unstable library feature `unicode_internals`
   --> $DIR/accidental-stable-in-unstable.rs:6:5
    |
 LL | use core::unicode::UNICODE_VERSION;
diff --git a/tests/ui/stability-attribute/allow-unstable-reexport.rs b/tests/ui/stability-attribute/allow-unstable-reexport.rs
index d2f1593c31a..b6ed2110918 100644
--- a/tests/ui/stability-attribute/allow-unstable-reexport.rs
+++ b/tests/ui/stability-attribute/allow-unstable-reexport.rs
@@ -20,11 +20,11 @@ pub use lint_stability_reexport::unstable_text;
 // Ensure items which aren't marked as unstable can't re-export unstable items
 #[stable(feature = "lint_stability", since = "1.0.0")]
 pub use lint_stability::unstable as unstable2;
-//~^ ERROR use of unstable library feature 'unstable_test_feature'
+//~^ ERROR use of unstable library feature `unstable_test_feature`
 
 fn main() {
     // Since we didn't enable the feature in this crate, we still can't
     // use these items, even though they're in scope from the `use`s which are now allowed.
-    unstable(); //~ ERROR use of unstable library feature 'unstable_test_feature'
-    unstable_text(); //~ ERROR use of unstable library feature 'unstable_test_feature'
+    unstable(); //~ ERROR use of unstable library feature `unstable_test_feature`
+    unstable_text(); //~ ERROR use of unstable library feature `unstable_test_feature`
 }
diff --git a/tests/ui/stability-attribute/allow-unstable-reexport.stderr b/tests/ui/stability-attribute/allow-unstable-reexport.stderr
index af75b6afb04..f869eeb790e 100644
--- a/tests/ui/stability-attribute/allow-unstable-reexport.stderr
+++ b/tests/ui/stability-attribute/allow-unstable-reexport.stderr
@@ -1,4 +1,4 @@
-error[E0658]: use of unstable library feature 'unstable_test_feature'
+error[E0658]: use of unstable library feature `unstable_test_feature`
   --> $DIR/allow-unstable-reexport.rs:22:9
    |
 LL | pub use lint_stability::unstable as unstable2;
@@ -7,7 +7,7 @@ LL | pub use lint_stability::unstable as unstable2;
    = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_test_feature'
+error[E0658]: use of unstable library feature `unstable_test_feature`
   --> $DIR/allow-unstable-reexport.rs:28:5
    |
 LL |     unstable();
@@ -16,7 +16,7 @@ LL |     unstable();
    = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_test_feature': text
+error[E0658]: use of unstable library feature `unstable_test_feature`: text
   --> $DIR/allow-unstable-reexport.rs:29:5
    |
 LL |     unstable_text();
diff --git a/tests/ui/stability-attribute/allowed-through-unstable.rs b/tests/ui/stability-attribute/allowed-through-unstable.rs
index 6bce5c87ddb..29911a70be9 100644
--- a/tests/ui/stability-attribute/allowed-through-unstable.rs
+++ b/tests/ui/stability-attribute/allowed-through-unstable.rs
@@ -6,4 +6,4 @@
 extern crate allowed_through_unstable_core;
 
 use allowed_through_unstable_core::unstable_module::OldStableTraitAllowedThoughUnstable;
-use allowed_through_unstable_core::unstable_module::NewStableTraitNotAllowedThroughUnstable; //~ ERROR use of unstable library feature 'unstable_test_feature'
+use allowed_through_unstable_core::unstable_module::NewStableTraitNotAllowedThroughUnstable; //~ ERROR use of unstable library feature `unstable_test_feature`
diff --git a/tests/ui/stability-attribute/allowed-through-unstable.stderr b/tests/ui/stability-attribute/allowed-through-unstable.stderr
index 5c8e6358b7c..00eea9f730d 100644
--- a/tests/ui/stability-attribute/allowed-through-unstable.stderr
+++ b/tests/ui/stability-attribute/allowed-through-unstable.stderr
@@ -1,4 +1,4 @@
-error[E0658]: use of unstable library feature 'unstable_test_feature'
+error[E0658]: use of unstable library feature `unstable_test_feature`
   --> $DIR/allowed-through-unstable.rs:9:5
    |
 LL | use allowed_through_unstable_core::unstable_module::NewStableTraitNotAllowedThroughUnstable;
diff --git a/tests/ui/stability-attribute/default-body-stability-err.stderr b/tests/ui/stability-attribute/default-body-stability-err.stderr
index 9d8ad81f102..6173de5020b 100644
--- a/tests/ui/stability-attribute/default-body-stability-err.stderr
+++ b/tests/ui/stability-attribute/default-body-stability-err.stderr
@@ -5,7 +5,7 @@ LL | impl JustTrait for Type {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: default implementation of `CONSTANT` is unstable
-   = note: use of unstable library feature 'constant_default_body'
+   = note: use of unstable library feature `constant_default_body`
    = help: add `#![feature(constant_default_body)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
@@ -16,7 +16,7 @@ LL | impl JustTrait for Type {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: default implementation of `fun` is unstable
-   = note: use of unstable library feature 'fun_default_body'
+   = note: use of unstable library feature `fun_default_body`
    = help: add `#![feature(fun_default_body)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
@@ -27,7 +27,7 @@ LL | impl JustTrait for Type {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: default implementation of `fun2` is unstable
-   = note: use of unstable library feature 'fun_default_body': reason
+   = note: use of unstable library feature `fun_default_body`: reason
    = help: add `#![feature(fun_default_body)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
@@ -43,7 +43,7 @@ LL | | }
    | |_^
    |
    = note: default implementation of `eq` is unstable
-   = note: use of unstable library feature 'eq_default_body'
+   = note: use of unstable library feature `eq_default_body`
    = help: add `#![feature(eq_default_body)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
diff --git a/tests/ui/stability-attribute/generics-default-stability-trait.rs b/tests/ui/stability-attribute/generics-default-stability-trait.rs
index ba8ee143d4a..a2302959638 100644
--- a/tests/ui/stability-attribute/generics-default-stability-trait.rs
+++ b/tests/ui/stability-attribute/generics-default-stability-trait.rs
@@ -13,15 +13,15 @@ impl Trait1 for S {
 
 struct S;
 
-impl Trait1<usize> for S { //~ ERROR use of unstable library feature 'unstable_default'
+impl Trait1<usize> for S { //~ ERROR use of unstable library feature `unstable_default`
     fn foo() -> usize { 0 }
 }
 
-impl Trait1<isize> for S { //~ ERROR use of unstable library feature 'unstable_default'
+impl Trait1<isize> for S { //~ ERROR use of unstable library feature `unstable_default`
     fn foo() -> isize { 0 }
 }
 
-impl Trait2<usize> for S { //~ ERROR use of unstable library feature 'unstable_default'
+impl Trait2<usize> for S { //~ ERROR use of unstable library feature `unstable_default`
     fn foo() -> usize { 0 }
 }
 
diff --git a/tests/ui/stability-attribute/generics-default-stability-trait.stderr b/tests/ui/stability-attribute/generics-default-stability-trait.stderr
index 699e7c83c70..21b21fdb945 100644
--- a/tests/ui/stability-attribute/generics-default-stability-trait.stderr
+++ b/tests/ui/stability-attribute/generics-default-stability-trait.stderr
@@ -1,4 +1,4 @@
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability-trait.rs:16:13
    |
 LL | impl Trait1<usize> for S {
@@ -7,7 +7,7 @@ LL | impl Trait1<usize> for S {
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability-trait.rs:20:13
    |
 LL | impl Trait1<isize> for S {
@@ -16,7 +16,7 @@ LL | impl Trait1<isize> for S {
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability-trait.rs:24:13
    |
 LL | impl Trait2<usize> for S {
diff --git a/tests/ui/stability-attribute/generics-default-stability-where.rs b/tests/ui/stability-attribute/generics-default-stability-where.rs
index f8a2fb4873a..a7bc1756d78 100644
--- a/tests/ui/stability-attribute/generics-default-stability-where.rs
+++ b/tests/ui/stability-attribute/generics-default-stability-where.rs
@@ -4,7 +4,7 @@ extern crate unstable_generic_param;
 
 use unstable_generic_param::*;
 
-impl<T> Trait3<usize> for T where T: Trait2<usize> { //~ ERROR use of unstable library feature 'unstable_default'
+impl<T> Trait3<usize> for T where T: Trait2<usize> { //~ ERROR use of unstable library feature `unstable_default`
 //~^ ERROR `T` must be used as the type parameter for some local type
     fn foo() -> usize { T::foo() }
 }
diff --git a/tests/ui/stability-attribute/generics-default-stability-where.stderr b/tests/ui/stability-attribute/generics-default-stability-where.stderr
index 8e4089970f5..9437f5d65fa 100644
--- a/tests/ui/stability-attribute/generics-default-stability-where.stderr
+++ b/tests/ui/stability-attribute/generics-default-stability-where.stderr
@@ -1,4 +1,4 @@
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability-where.rs:7:45
    |
 LL | impl<T> Trait3<usize> for T where T: Trait2<usize> {
diff --git a/tests/ui/stability-attribute/generics-default-stability.rs b/tests/ui/stability-attribute/generics-default-stability.rs
index abd45b651ee..e1b3971f70c 100644
--- a/tests/ui/stability-attribute/generics-default-stability.rs
+++ b/tests/ui/stability-attribute/generics-default-stability.rs
@@ -20,12 +20,12 @@ impl Trait3<usize> for S {
 fn main() {
     let _ = S;
 
-    let _: Struct1<isize> = Struct1 { field: 1 }; //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Struct1<isize> = Struct1 { field: 1 }; //~ ERROR use of unstable library feature `unstable_default`
 
     let _ = STRUCT1; // ok
     let _: Struct1 = STRUCT1; // ok
-    let _: Struct1<usize> = STRUCT1; //~ ERROR use of unstable library feature 'unstable_default'
-    let _: Struct1<isize> = Struct1 { field: 0 }; //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Struct1<usize> = STRUCT1; //~ ERROR use of unstable library feature `unstable_default`
+    let _: Struct1<isize> = Struct1 { field: 0 }; //~ ERROR use of unstable library feature `unstable_default`
 
     // Instability is not enforced for generic type parameters used in public fields.
     // Note how the unstable type default `usize` leaks,
@@ -54,10 +54,10 @@ fn main() {
 
     let _ = STRUCT3;
     let _: Struct3 = STRUCT3; // ok
-    let _: Struct3<isize, usize> = STRUCT3; //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Struct3<isize, usize> = STRUCT3; //~ ERROR use of unstable library feature `unstable_default`
     let _: Struct3<isize> = STRUCT3; // ok
-    let _: Struct3<isize, isize> = Struct3 { field1: 0, field2: 0 }; //~ ERROR use of unstable library feature 'unstable_default'
-    let _: Struct3<usize, usize> = Struct3 { field1: 0, field2: 0 }; //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Struct3<isize, isize> = Struct3 { field1: 0, field2: 0 }; //~ ERROR use of unstable library feature `unstable_default`
+    let _: Struct3<usize, usize> = Struct3 { field1: 0, field2: 0 }; //~ ERROR use of unstable library feature `unstable_default`
     let _ = STRUCT3.field1; // ok
     let _: isize = STRUCT3.field1; // ok
     let _ = STRUCT3.field1 + 1; // ok
@@ -81,15 +81,15 @@ fn main() {
     //~^^^ use of deprecated field `unstable_generic_param::Struct4::field`: test [deprecated]
 
     let _ = STRUCT5;
-    let _: Struct5<isize> = Struct5 { field: 1 }; //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Struct5<isize> = Struct5 { field: 1 }; //~ ERROR use of unstable library feature `unstable_default`
     //~^ use of deprecated struct `unstable_generic_param::Struct5`: test [deprecated]
     //~^^ use of deprecated struct `unstable_generic_param::Struct5`: test [deprecated]
     //~^^^ use of deprecated field `unstable_generic_param::Struct5::field`: test [deprecated]
     let _ = STRUCT5;
     let _: Struct5 = STRUCT5; //~ use of deprecated struct `unstable_generic_param::Struct5`: test [deprecated]
-    let _: Struct5<usize> = STRUCT5; //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Struct5<usize> = STRUCT5; //~ ERROR use of unstable library feature `unstable_default`
     //~^ use of deprecated struct `unstable_generic_param::Struct5`: test [deprecated]
-    let _: Struct5<isize> = Struct5 { field: 0 }; //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Struct5<isize> = Struct5 { field: 0 }; //~ ERROR use of unstable library feature `unstable_default`
     //~^ use of deprecated struct `unstable_generic_param::Struct5`: test [deprecated]
     //~^^ use of deprecated struct `unstable_generic_param::Struct5`: test [deprecated]
     //~^^^ use of deprecated field `unstable_generic_param::Struct5::field`: test [deprecated]
@@ -97,12 +97,12 @@ fn main() {
     let _: Struct6<isize> = Struct6 { field: 1 }; // ok
     let _: Struct6<isize> = Struct6 { field: 0 }; // ok
 
-    let _: Alias1<isize> = Alias1::Some(1); //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Alias1<isize> = Alias1::Some(1); //~ ERROR use of unstable library feature `unstable_default`
 
     let _ = ALIAS1; // ok
     let _: Alias1 = ALIAS1; // ok
-    let _: Alias1<usize> = ALIAS1; //~ ERROR use of unstable library feature 'unstable_default'
-    let _: Alias1<isize> = Alias1::Some(0); //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Alias1<usize> = ALIAS1; //~ ERROR use of unstable library feature `unstable_default`
+    let _: Alias1<isize> = Alias1::Some(0); //~ ERROR use of unstable library feature `unstable_default`
 
     // Instability is not enforced for generic type parameters used in public fields.
     // Note how the unstable type default `usize` leaks,
@@ -130,10 +130,10 @@ fn main() {
 
     let _ = ALIAS3;
     let _: Alias3 = ALIAS3; // ok
-    let _: Alias3<isize, usize> = ALIAS3; //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Alias3<isize, usize> = ALIAS3; //~ ERROR use of unstable library feature `unstable_default`
     let _: Alias3<isize> = ALIAS3; // ok
-    let _: Alias3<isize, isize> = Alias3::Ok(0); //~ ERROR use of unstable library feature 'unstable_default'
-    let _: Alias3<usize, usize> = Alias3::Ok(0); //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Alias3<isize, isize> = Alias3::Ok(0); //~ ERROR use of unstable library feature `unstable_default`
+    let _: Alias3<usize, usize> = Alias3::Ok(0); //~ ERROR use of unstable library feature `unstable_default`
     let _ = ALIAS3.unwrap(); // ok
     let _: isize = ALIAS3.unwrap(); // ok
     let _ = ALIAS3.unwrap() + 1; // ok
@@ -155,26 +155,26 @@ fn main() {
     //~^^ use of deprecated type alias `unstable_generic_param::Alias4`: test [deprecated]
 
     let _ = ALIAS5;
-    let _: Alias5<isize> = Alias5::Some(1); //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Alias5<isize> = Alias5::Some(1); //~ ERROR use of unstable library feature `unstable_default`
     //~^ use of deprecated type alias `unstable_generic_param::Alias5`: test [deprecated]
     //~^^ use of deprecated type alias `unstable_generic_param::Alias5`: test [deprecated]
     let _ = ALIAS5;
     let _: Alias5 = ALIAS5; //~ use of deprecated type alias `unstable_generic_param::Alias5`: test [deprecated]
-    let _: Alias5<usize> = ALIAS5; //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Alias5<usize> = ALIAS5; //~ ERROR use of unstable library feature `unstable_default`
     //~^ use of deprecated type alias `unstable_generic_param::Alias5`: test [deprecated]
-    let _: Alias5<isize> = Alias5::Some(0); //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Alias5<isize> = Alias5::Some(0); //~ ERROR use of unstable library feature `unstable_default`
     //~^ use of deprecated type alias `unstable_generic_param::Alias5`: test [deprecated]
     //~^^ use of deprecated type alias `unstable_generic_param::Alias5`: test [deprecated]
 
     let _: Alias6<isize> = Alias6::Some(1); // ok
     let _: Alias6<isize> = Alias6::Some(0); // ok
 
-    let _: Enum1<isize> = Enum1::Some(1); //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Enum1<isize> = Enum1::Some(1); //~ ERROR use of unstable library feature `unstable_default`
 
     let _ = ENUM1; // ok
     let _: Enum1 = ENUM1; // ok
-    let _: Enum1<usize> = ENUM1; //~ ERROR use of unstable library feature 'unstable_default'
-    let _: Enum1<isize> = Enum1::Some(0); //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Enum1<usize> = ENUM1; //~ ERROR use of unstable library feature `unstable_default`
+    let _: Enum1<isize> = Enum1::Some(0); //~ ERROR use of unstable library feature `unstable_default`
 
     // Instability is not enforced for generic type parameters used in public fields.
     // Note how the unstable type default `usize` leaks,
@@ -202,10 +202,10 @@ fn main() {
 
     let _ = ENUM3;
     let _: Enum3 = ENUM3; // ok
-    let _: Enum3<isize, usize> = ENUM3; //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Enum3<isize, usize> = ENUM3; //~ ERROR use of unstable library feature `unstable_default`
     let _: Enum3<isize> = ENUM3; // ok
-    let _: Enum3<isize, isize> = Enum3::Ok(0); //~ ERROR use of unstable library feature 'unstable_default'
-    let _: Enum3<usize, usize> = Enum3::Ok(0); //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Enum3<isize, isize> = Enum3::Ok(0); //~ ERROR use of unstable library feature `unstable_default`
+    let _: Enum3<usize, usize> = Enum3::Ok(0); //~ ERROR use of unstable library feature `unstable_default`
     if let Enum3::Ok(x) = ENUM3 {let _ = x;} // ok
     if let Enum3::Ok(x) = ENUM3 {let _: isize = x;} // ok
     if let Enum3::Ok(x) = ENUM3 {let _ = x + 1;} // ok
@@ -227,21 +227,21 @@ fn main() {
     //~^^ use of deprecated enum `unstable_generic_param::Enum4`: test [deprecated]
 
     let _ = ENUM5;
-    let _: Enum5<isize> = Enum5::Some(1); //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Enum5<isize> = Enum5::Some(1); //~ ERROR use of unstable library feature `unstable_default`
     //~^ use of deprecated tuple variant `unstable_generic_param::Enum5::Some`: test [deprecated]
     //~^^ use of deprecated enum `unstable_generic_param::Enum5`: test [deprecated]
     let _ = ENUM5;
     let _: Enum5 = ENUM5; //~ use of deprecated enum `unstable_generic_param::Enum5`: test [deprecated]
-    let _: Enum5<usize> = ENUM5; //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Enum5<usize> = ENUM5; //~ ERROR use of unstable library feature `unstable_default`
     //~^ use of deprecated enum `unstable_generic_param::Enum5`: test [deprecated]
-    let _: Enum5<isize> = Enum5::Some(0); //~ ERROR use of unstable library feature 'unstable_default'
+    let _: Enum5<isize> = Enum5::Some(0); //~ ERROR use of unstable library feature `unstable_default`
     //~^ use of deprecated tuple variant `unstable_generic_param::Enum5::Some`: test [deprecated]
     //~^^ use of deprecated enum `unstable_generic_param::Enum5`: test [deprecated]
 
     let _: Enum6<isize> = Enum6::Some(1); // ok
     let _: Enum6<isize> = Enum6::Some(0); // ok
 
-    let _: Box1<isize, System> = Box1::new(1); //~ ERROR use of unstable library feature 'box_alloc_param'
+    let _: Box1<isize, System> = Box1::new(1); //~ ERROR use of unstable library feature `box_alloc_param`
     let _: Box1<isize> = Box1::new(1); // ok
 
     let _: Box2<isize, System> = Box2::new(1); // ok
diff --git a/tests/ui/stability-attribute/generics-default-stability.stderr b/tests/ui/stability-attribute/generics-default-stability.stderr
index b1b91a850e9..f4f51a14248 100644
--- a/tests/ui/stability-attribute/generics-default-stability.stderr
+++ b/tests/ui/stability-attribute/generics-default-stability.stderr
@@ -216,7 +216,7 @@ warning: use of deprecated enum `unstable_generic_param::Enum5`: test
 LL |     let _: Enum5<isize> = Enum5::Some(0);
    |            ^^^^^
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:23:20
    |
 LL |     let _: Struct1<isize> = Struct1 { field: 1 };
@@ -225,7 +225,7 @@ LL |     let _: Struct1<isize> = Struct1 { field: 1 };
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:27:20
    |
 LL |     let _: Struct1<usize> = STRUCT1;
@@ -234,7 +234,7 @@ LL |     let _: Struct1<usize> = STRUCT1;
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:28:20
    |
 LL |     let _: Struct1<isize> = Struct1 { field: 0 };
@@ -243,7 +243,7 @@ LL |     let _: Struct1<isize> = Struct1 { field: 0 };
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:57:27
    |
 LL |     let _: Struct3<isize, usize> = STRUCT3;
@@ -252,7 +252,7 @@ LL |     let _: Struct3<isize, usize> = STRUCT3;
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:59:27
    |
 LL |     let _: Struct3<isize, isize> = Struct3 { field1: 0, field2: 0 };
@@ -261,7 +261,7 @@ LL |     let _: Struct3<isize, isize> = Struct3 { field1: 0, field2: 0 };
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:60:27
    |
 LL |     let _: Struct3<usize, usize> = Struct3 { field1: 0, field2: 0 };
@@ -270,7 +270,7 @@ LL |     let _: Struct3<usize, usize> = Struct3 { field1: 0, field2: 0 };
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:84:20
    |
 LL |     let _: Struct5<isize> = Struct5 { field: 1 };
@@ -279,7 +279,7 @@ LL |     let _: Struct5<isize> = Struct5 { field: 1 };
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:90:20
    |
 LL |     let _: Struct5<usize> = STRUCT5;
@@ -288,7 +288,7 @@ LL |     let _: Struct5<usize> = STRUCT5;
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:92:20
    |
 LL |     let _: Struct5<isize> = Struct5 { field: 0 };
@@ -297,7 +297,7 @@ LL |     let _: Struct5<isize> = Struct5 { field: 0 };
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:100:19
    |
 LL |     let _: Alias1<isize> = Alias1::Some(1);
@@ -306,7 +306,7 @@ LL |     let _: Alias1<isize> = Alias1::Some(1);
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:104:19
    |
 LL |     let _: Alias1<usize> = ALIAS1;
@@ -315,7 +315,7 @@ LL |     let _: Alias1<usize> = ALIAS1;
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:105:19
    |
 LL |     let _: Alias1<isize> = Alias1::Some(0);
@@ -324,7 +324,7 @@ LL |     let _: Alias1<isize> = Alias1::Some(0);
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:133:26
    |
 LL |     let _: Alias3<isize, usize> = ALIAS3;
@@ -333,7 +333,7 @@ LL |     let _: Alias3<isize, usize> = ALIAS3;
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:135:26
    |
 LL |     let _: Alias3<isize, isize> = Alias3::Ok(0);
@@ -342,7 +342,7 @@ LL |     let _: Alias3<isize, isize> = Alias3::Ok(0);
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:136:26
    |
 LL |     let _: Alias3<usize, usize> = Alias3::Ok(0);
@@ -351,7 +351,7 @@ LL |     let _: Alias3<usize, usize> = Alias3::Ok(0);
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:158:19
    |
 LL |     let _: Alias5<isize> = Alias5::Some(1);
@@ -360,7 +360,7 @@ LL |     let _: Alias5<isize> = Alias5::Some(1);
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:163:19
    |
 LL |     let _: Alias5<usize> = ALIAS5;
@@ -369,7 +369,7 @@ LL |     let _: Alias5<usize> = ALIAS5;
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:165:19
    |
 LL |     let _: Alias5<isize> = Alias5::Some(0);
@@ -378,7 +378,7 @@ LL |     let _: Alias5<isize> = Alias5::Some(0);
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:172:18
    |
 LL |     let _: Enum1<isize> = Enum1::Some(1);
@@ -387,7 +387,7 @@ LL |     let _: Enum1<isize> = Enum1::Some(1);
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:176:18
    |
 LL |     let _: Enum1<usize> = ENUM1;
@@ -396,7 +396,7 @@ LL |     let _: Enum1<usize> = ENUM1;
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:177:18
    |
 LL |     let _: Enum1<isize> = Enum1::Some(0);
@@ -405,7 +405,7 @@ LL |     let _: Enum1<isize> = Enum1::Some(0);
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:205:25
    |
 LL |     let _: Enum3<isize, usize> = ENUM3;
@@ -414,7 +414,7 @@ LL |     let _: Enum3<isize, usize> = ENUM3;
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:207:25
    |
 LL |     let _: Enum3<isize, isize> = Enum3::Ok(0);
@@ -423,7 +423,7 @@ LL |     let _: Enum3<isize, isize> = Enum3::Ok(0);
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:208:25
    |
 LL |     let _: Enum3<usize, usize> = Enum3::Ok(0);
@@ -432,7 +432,7 @@ LL |     let _: Enum3<usize, usize> = Enum3::Ok(0);
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:230:18
    |
 LL |     let _: Enum5<isize> = Enum5::Some(1);
@@ -441,7 +441,7 @@ LL |     let _: Enum5<isize> = Enum5::Some(1);
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:235:18
    |
 LL |     let _: Enum5<usize> = ENUM5;
@@ -450,7 +450,7 @@ LL |     let _: Enum5<usize> = ENUM5;
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_default'
+error[E0658]: use of unstable library feature `unstable_default`
   --> $DIR/generics-default-stability.rs:237:18
    |
 LL |     let _: Enum5<isize> = Enum5::Some(0);
@@ -459,7 +459,7 @@ LL |     let _: Enum5<isize> = Enum5::Some(0);
    = help: add `#![feature(unstable_default)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'box_alloc_param'
+error[E0658]: use of unstable library feature `box_alloc_param`
   --> $DIR/generics-default-stability.rs:244:24
    |
 LL |     let _: Box1<isize, System> = Box1::new(1);
diff --git a/tests/ui/stability-attribute/issue-28075.rs b/tests/ui/stability-attribute/issue-28075.rs
index 8fc2ffe3dc9..b6b231d4afa 100644
--- a/tests/ui/stability-attribute/issue-28075.rs
+++ b/tests/ui/stability-attribute/issue-28075.rs
@@ -7,7 +7,7 @@
 extern crate lint_stability;
 
 use lint_stability::{unstable, deprecated};
-//~^ ERROR use of unstable library feature 'unstable_test_feature'
+//~^ ERROR use of unstable library feature `unstable_test_feature`
 
 fn main() {
 }
diff --git a/tests/ui/stability-attribute/issue-28075.stderr b/tests/ui/stability-attribute/issue-28075.stderr
index 282686d82bb..d10a27b874e 100644
--- a/tests/ui/stability-attribute/issue-28075.stderr
+++ b/tests/ui/stability-attribute/issue-28075.stderr
@@ -1,4 +1,4 @@
-error[E0658]: use of unstable library feature 'unstable_test_feature'
+error[E0658]: use of unstable library feature `unstable_test_feature`
   --> $DIR/issue-28075.rs:9:22
    |
 LL | use lint_stability::{unstable, deprecated};
diff --git a/tests/ui/stability-attribute/issue-28388-3.rs b/tests/ui/stability-attribute/issue-28388-3.rs
index 2f61146f6e3..7b6b6ce7f4b 100644
--- a/tests/ui/stability-attribute/issue-28388-3.rs
+++ b/tests/ui/stability-attribute/issue-28388-3.rs
@@ -5,7 +5,7 @@
 extern crate lint_stability;
 
 use lint_stability::UnstableEnum::{};
-//~^ ERROR use of unstable library feature 'unstable_test_feature'
+//~^ ERROR use of unstable library feature `unstable_test_feature`
 use lint_stability::StableEnum::{}; // OK
 
 fn main() {}
diff --git a/tests/ui/stability-attribute/issue-28388-3.stderr b/tests/ui/stability-attribute/issue-28388-3.stderr
index 56ca57591ce..def27c0b44d 100644
--- a/tests/ui/stability-attribute/issue-28388-3.stderr
+++ b/tests/ui/stability-attribute/issue-28388-3.stderr
@@ -1,4 +1,4 @@
-error[E0658]: use of unstable library feature 'unstable_test_feature'
+error[E0658]: use of unstable library feature `unstable_test_feature`
   --> $DIR/issue-28388-3.rs:7:5
    |
 LL | use lint_stability::UnstableEnum::{};
diff --git a/tests/ui/stability-attribute/stability-attribute-implies-no-feature.rs b/tests/ui/stability-attribute/stability-attribute-implies-no-feature.rs
index 47f885a43d6..0cc1dd20fd8 100644
--- a/tests/ui/stability-attribute/stability-attribute-implies-no-feature.rs
+++ b/tests/ui/stability-attribute/stability-attribute-implies-no-feature.rs
@@ -5,9 +5,9 @@
 
 extern crate stability_attribute_implies;
 use stability_attribute_implies::{foo, foobar};
-//~^ ERROR use of unstable library feature 'foobar'
+//~^ ERROR use of unstable library feature `foobar`
 
 fn main() {
     foo(); // no error - stable
-    foobar(); //~ ERROR use of unstable library feature 'foobar'
+    foobar(); //~ ERROR use of unstable library feature `foobar`
 }
diff --git a/tests/ui/stability-attribute/stability-attribute-implies-no-feature.stderr b/tests/ui/stability-attribute/stability-attribute-implies-no-feature.stderr
index b35ee6c1291..a625ef504b1 100644
--- a/tests/ui/stability-attribute/stability-attribute-implies-no-feature.stderr
+++ b/tests/ui/stability-attribute/stability-attribute-implies-no-feature.stderr
@@ -1,4 +1,4 @@
-error[E0658]: use of unstable library feature 'foobar'
+error[E0658]: use of unstable library feature `foobar`
   --> $DIR/stability-attribute-implies-no-feature.rs:7:40
    |
 LL | use stability_attribute_implies::{foo, foobar};
@@ -8,7 +8,7 @@ LL | use stability_attribute_implies::{foo, foobar};
    = help: add `#![feature(foobar)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'foobar'
+error[E0658]: use of unstable library feature `foobar`
   --> $DIR/stability-attribute-implies-no-feature.rs:12:5
    |
 LL |     foobar();
diff --git a/tests/ui/stability-attribute/stability-attribute-issue.rs b/tests/ui/stability-attribute/stability-attribute-issue.rs
index 2d25c0c8bd7..e9d1f144e6b 100644
--- a/tests/ui/stability-attribute/stability-attribute-issue.rs
+++ b/tests/ui/stability-attribute/stability-attribute-issue.rs
@@ -6,7 +6,7 @@ use stability_attribute_issue::*;
 
 fn main() {
     unstable();
-    //~^ ERROR use of unstable library feature 'unstable_test_feature'
+    //~^ ERROR use of unstable library feature `unstable_test_feature`
     unstable_msg();
-    //~^ ERROR use of unstable library feature 'unstable_test_feature': message
+    //~^ ERROR use of unstable library feature `unstable_test_feature`: message
 }
diff --git a/tests/ui/stability-attribute/stability-attribute-issue.stderr b/tests/ui/stability-attribute/stability-attribute-issue.stderr
index 336e0f1718f..9dc6f441987 100644
--- a/tests/ui/stability-attribute/stability-attribute-issue.stderr
+++ b/tests/ui/stability-attribute/stability-attribute-issue.stderr
@@ -1,4 +1,4 @@
-error[E0658]: use of unstable library feature 'unstable_test_feature'
+error[E0658]: use of unstable library feature `unstable_test_feature`
   --> $DIR/stability-attribute-issue.rs:8:5
    |
 LL |     unstable();
@@ -8,7 +8,7 @@ LL |     unstable();
    = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_test_feature': message
+error[E0658]: use of unstable library feature `unstable_test_feature`: message
   --> $DIR/stability-attribute-issue.rs:10:5
    |
 LL |     unstable_msg();
diff --git a/tests/ui/stability-attribute/stable-in-unstable.rs b/tests/ui/stability-attribute/stable-in-unstable.rs
index d10845d49a3..1fe084f6e59 100644
--- a/tests/ui/stability-attribute/stable-in-unstable.rs
+++ b/tests/ui/stability-attribute/stable-in-unstable.rs
@@ -13,8 +13,8 @@ extern crate stable_in_unstable_core;
 extern crate stable_in_unstable_std;
 
 mod isolated1 {
-    use stable_in_unstable_core::new_unstable_module; //~ ERROR use of unstable library feature 'unstable_test_feature'
-    use stable_in_unstable_core::new_unstable_module::OldTrait; //~ ERROR use of unstable library feature 'unstable_test_feature'
+    use stable_in_unstable_core::new_unstable_module; //~ ERROR use of unstable library feature `unstable_test_feature`
+    use stable_in_unstable_core::new_unstable_module::OldTrait; //~ ERROR use of unstable library feature `unstable_test_feature`
 }
 
 mod isolated2 {
@@ -26,7 +26,7 @@ mod isolated2 {
 }
 
 mod isolated3 {
-    use stable_in_unstable_core::new_unstable_module::OldTrait; //~ ERROR use of unstable library feature 'unstable_test_feature'
+    use stable_in_unstable_core::new_unstable_module::OldTrait; //~ ERROR use of unstable library feature `unstable_test_feature`
 
     struct LocalType;
 
@@ -36,7 +36,7 @@ mod isolated3 {
 mod isolated4 {
     struct LocalType;
 
-    impl stable_in_unstable_core::new_unstable_module::OldTrait for LocalType {} //~ ERROR use of unstable library feature 'unstable_test_feature'
+    impl stable_in_unstable_core::new_unstable_module::OldTrait for LocalType {} //~ ERROR use of unstable library feature `unstable_test_feature`
 }
 
 mod isolated5 {
@@ -46,9 +46,9 @@ mod isolated5 {
 }
 
 mod isolated6 {
-    use stable_in_unstable_core::new_unstable_module::{OldTrait}; //~ ERROR use of unstable library feature 'unstable_test_feature'
+    use stable_in_unstable_core::new_unstable_module::{OldTrait}; //~ ERROR use of unstable library feature `unstable_test_feature`
 }
 
 mod isolated7 {
-    use stable_in_unstable_core::new_unstable_module::*; //~ ERROR use of unstable library feature 'unstable_test_feature'
+    use stable_in_unstable_core::new_unstable_module::*; //~ ERROR use of unstable library feature `unstable_test_feature`
 }
diff --git a/tests/ui/stability-attribute/stable-in-unstable.stderr b/tests/ui/stability-attribute/stable-in-unstable.stderr
index eb73f047acd..b37b4dfd586 100644
--- a/tests/ui/stability-attribute/stable-in-unstable.stderr
+++ b/tests/ui/stability-attribute/stable-in-unstable.stderr
@@ -1,4 +1,4 @@
-error[E0658]: use of unstable library feature 'unstable_test_feature'
+error[E0658]: use of unstable library feature `unstable_test_feature`
   --> $DIR/stable-in-unstable.rs:16:9
    |
 LL |     use stable_in_unstable_core::new_unstable_module;
@@ -8,7 +8,7 @@ LL |     use stable_in_unstable_core::new_unstable_module;
    = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_test_feature'
+error[E0658]: use of unstable library feature `unstable_test_feature`
   --> $DIR/stable-in-unstable.rs:17:9
    |
 LL |     use stable_in_unstable_core::new_unstable_module::OldTrait;
@@ -18,7 +18,7 @@ LL |     use stable_in_unstable_core::new_unstable_module::OldTrait;
    = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_test_feature'
+error[E0658]: use of unstable library feature `unstable_test_feature`
   --> $DIR/stable-in-unstable.rs:29:9
    |
 LL |     use stable_in_unstable_core::new_unstable_module::OldTrait;
@@ -28,7 +28,7 @@ LL |     use stable_in_unstable_core::new_unstable_module::OldTrait;
    = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_test_feature'
+error[E0658]: use of unstable library feature `unstable_test_feature`
   --> $DIR/stable-in-unstable.rs:39:10
    |
 LL |     impl stable_in_unstable_core::new_unstable_module::OldTrait for LocalType {}
@@ -38,7 +38,7 @@ LL |     impl stable_in_unstable_core::new_unstable_module::OldTrait for LocalTy
    = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_test_feature'
+error[E0658]: use of unstable library feature `unstable_test_feature`
   --> $DIR/stable-in-unstable.rs:49:56
    |
 LL |     use stable_in_unstable_core::new_unstable_module::{OldTrait};
@@ -48,7 +48,7 @@ LL |     use stable_in_unstable_core::new_unstable_module::{OldTrait};
    = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'unstable_test_feature'
+error[E0658]: use of unstable library feature `unstable_test_feature`
   --> $DIR/stable-in-unstable.rs:53:9
    |
 LL |     use stable_in_unstable_core::new_unstable_module::*;
diff --git a/tests/ui/stability-attribute/suggest-vec-allocator-api.rs b/tests/ui/stability-attribute/suggest-vec-allocator-api.rs
index fac52ab77c6..61a48c19e72 100644
--- a/tests/ui/stability-attribute/suggest-vec-allocator-api.rs
+++ b/tests/ui/stability-attribute/suggest-vec-allocator-api.rs
@@ -1,9 +1,9 @@
 fn main() {
-    let _: Vec<u8, _> = vec![]; //~ ERROR use of unstable library feature 'allocator_api'
+    let _: Vec<u8, _> = vec![]; //~ ERROR use of unstable library feature `allocator_api`
     #[rustfmt::skip]
     let _: Vec<
         String,
-        _> = vec![]; //~ ERROR use of unstable library feature 'allocator_api'
-    let _ = Vec::<u16, _>::new(); //~ ERROR use of unstable library feature 'allocator_api'
-    let _boxed: Box<u32, _> = Box::new(10); //~ ERROR use of unstable library feature 'allocator_api'
+        _> = vec![]; //~ ERROR use of unstable library feature `allocator_api`
+    let _ = Vec::<u16, _>::new(); //~ ERROR use of unstable library feature `allocator_api`
+    let _boxed: Box<u32, _> = Box::new(10); //~ ERROR use of unstable library feature `allocator_api`
 }
diff --git a/tests/ui/stability-attribute/suggest-vec-allocator-api.stderr b/tests/ui/stability-attribute/suggest-vec-allocator-api.stderr
index d7fcba4ced5..6662ceda90b 100644
--- a/tests/ui/stability-attribute/suggest-vec-allocator-api.stderr
+++ b/tests/ui/stability-attribute/suggest-vec-allocator-api.stderr
@@ -1,4 +1,4 @@
-error[E0658]: use of unstable library feature 'allocator_api'
+error[E0658]: use of unstable library feature `allocator_api`
   --> $DIR/suggest-vec-allocator-api.rs:2:20
    |
 LL |     let _: Vec<u8, _> = vec![];
@@ -10,7 +10,7 @@ LL |     let _: Vec<u8, _> = vec![];
    = help: add `#![feature(allocator_api)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'allocator_api'
+error[E0658]: use of unstable library feature `allocator_api`
   --> $DIR/suggest-vec-allocator-api.rs:6:9
    |
 LL |         _> = vec![];
@@ -26,7 +26,7 @@ LL +         String,
 LL ~         _)> = vec![];
    |
 
-error[E0658]: use of unstable library feature 'allocator_api'
+error[E0658]: use of unstable library feature `allocator_api`
   --> $DIR/suggest-vec-allocator-api.rs:8:26
    |
 LL |     let _boxed: Box<u32, _> = Box::new(10);
@@ -36,7 +36,7 @@ LL |     let _boxed: Box<u32, _> = Box::new(10);
    = help: add `#![feature(allocator_api)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: use of unstable library feature 'allocator_api'
+error[E0658]: use of unstable library feature `allocator_api`
   --> $DIR/suggest-vec-allocator-api.rs:7:24
    |
 LL |     let _ = Vec::<u16, _>::new();