Rollup merge of #62646 - estebank:wording, r=petrochenkov

Tweak wording in feature gate errors

Author: Mark-Simulacrum

src/libsyntax/feature_gate.rs

@@ -1451,7 +1451,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     template!(Word),
     Gated(Stability::Unstable,
         sym::dropck_eyepatch,
-        "may_dangle has unstable semantics and may be removed in the future",
+        "`may_dangle` has unstable semantics and may be removed in the future",
         cfg_fn!(dropck_eyepatch))),
     (sym::unwind, Whitelisted, template!(List: "allowed|aborts"), Gated(Stability::Unstable,
                                 sym::unwind_attributes,
@@ -1693,8 +1693,8 @@ impl<'a> Context<'a> {
             // Only run the custom attribute lint during regular feature gate
             // checking. Macro gating runs before the plugin attributes are
             // registered, so we skip this in that case.
-            let msg = format!("The attribute `{}` is currently unknown to the compiler and \
-                                may have meaning added to it in the future", attr.path);
+            let msg = format!("the attribute `{}` is currently unknown to the compiler and \
+                               may have meaning added to it in the future", attr.path);
             gate_feature!(self, custom_attribute, attr.span, &msg);
         }
     }

src/test/ui/conditional-compilation/cfg-generic-params.stderr

@@ -16,7 +16,7 @@ error: only lifetime parameters can be used in this context
 LL | struct WhereBad where for<#[cfg(no)] 'a, #[cfg(yes)] T> u8: Copy;
    |                                                      ^
 
-error[E0658]: The attribute `unknown` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `unknown` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/cfg-generic-params.rs:19:29
    |
 LL | fn f_lt_yes<#[cfg_attr(yes, unknown)] 'a>() {}
@@ -25,7 +25,7 @@ LL | fn f_lt_yes<#[cfg_attr(yes, unknown)] 'a>() {}
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `unknown` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `unknown` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/cfg-generic-params.rs:21:29
    |
 LL | fn f_ty_yes<#[cfg_attr(yes, unknown)] T>() {}
@@ -34,7 +34,7 @@ LL | fn f_ty_yes<#[cfg_attr(yes, unknown)] T>() {}
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `unknown` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `unknown` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/cfg-generic-params.rs:24:34
    |
 LL | type FnYes = for<#[cfg_attr(yes, unknown)] 'a> fn();
@@ -43,7 +43,7 @@ LL | type FnYes = for<#[cfg_attr(yes, unknown)] 'a> fn();
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `unknown` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `unknown` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/cfg-generic-params.rs:28:40
    |
 LL | type PolyYes = dyn for<#[cfg_attr(yes, unknown)] 'a> Copy;
@@ -52,7 +52,7 @@ LL | type PolyYes = dyn for<#[cfg_attr(yes, unknown)] 'a> Copy;
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `unknown` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `unknown` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/cfg-generic-params.rs:32:43
    |
 LL | struct WhereYes where for<#[cfg_attr(yes, unknown)] 'a> u8: Copy;

src/test/ui/feature-gates/feature-gate-custom_attribute2.rs

@@ -4,54 +4,54 @@
 // gate-test-custom_attribute
 
 struct StLt<#[lt_struct] 'a>(&'a u32);
-//~^ ERROR The attribute `lt_struct` is currently unknown to the compiler
+//~^ ERROR the attribute `lt_struct` is currently unknown to the compiler
 struct StTy<#[ty_struct] I>(I);
-//~^ ERROR The attribute `ty_struct` is currently unknown to the compiler
+//~^ ERROR the attribute `ty_struct` is currently unknown to the compiler
 
 enum EnLt<#[lt_enum] 'b> { A(&'b u32), B }
-//~^ ERROR The attribute `lt_enum` is currently unknown to the compiler
+//~^ ERROR the attribute `lt_enum` is currently unknown to the compiler
 enum EnTy<#[ty_enum] J> { A(J), B }
-//~^ ERROR The attribute `ty_enum` is currently unknown to the compiler
+//~^ ERROR the attribute `ty_enum` is currently unknown to the compiler
 
 trait TrLt<#[lt_trait] 'c> { fn foo(&self, _: &'c [u32]) -> &'c u32; }
-//~^ ERROR The attribute `lt_trait` is currently unknown to the compiler
+//~^ ERROR the attribute `lt_trait` is currently unknown to the compiler
 trait TrTy<#[ty_trait] K> { fn foo(&self, _: K); }
-//~^ ERROR The attribute `ty_trait` is currently unknown to the compiler
+//~^ ERROR the attribute `ty_trait` is currently unknown to the compiler
 
 type TyLt<#[lt_type] 'd> = &'d u32;
-//~^ ERROR The attribute `lt_type` is currently unknown to the compiler
+//~^ ERROR the attribute `lt_type` is currently unknown to the compiler
 type TyTy<#[ty_type] L> = (L, );
-//~^ ERROR The attribute `ty_type` is currently unknown to the compiler
+//~^ ERROR the attribute `ty_type` is currently unknown to the compiler
 
 impl<#[lt_inherent] 'e> StLt<'e> { }
-//~^ ERROR The attribute `lt_inherent` is currently unknown to the compiler
+//~^ ERROR the attribute `lt_inherent` is currently unknown to the compiler
 impl<#[ty_inherent] M> StTy<M> { }
-//~^ ERROR The attribute `ty_inherent` is currently unknown to the compiler
+//~^ ERROR the attribute `ty_inherent` is currently unknown to the compiler
 
 impl<#[lt_impl_for] 'f> TrLt<'f> for StLt<'f> {
-    //~^ ERROR The attribute `lt_impl_for` is currently unknown to the compiler
+    //~^ ERROR the attribute `lt_impl_for` is currently unknown to the compiler
     fn foo(&self, _: &'f [u32]) -> &'f u32 { loop { } }
 }
 impl<#[ty_impl_for] N> TrTy<N> for StTy<N> {
-    //~^ ERROR The attribute `ty_impl_for` is currently unknown to the compiler
+    //~^ ERROR the attribute `ty_impl_for` is currently unknown to the compiler
     fn foo(&self, _: N) { }
 }
 
 fn f_lt<#[lt_fn] 'g>(_: &'g [u32]) -> &'g u32 { loop { } }
-//~^ ERROR The attribute `lt_fn` is currently unknown to the compiler
+//~^ ERROR the attribute `lt_fn` is currently unknown to the compiler
 fn f_ty<#[ty_fn] O>(_: O) { }
-//~^ ERROR The attribute `ty_fn` is currently unknown to the compiler
+//~^ ERROR the attribute `ty_fn` is currently unknown to the compiler
 
 impl<I> StTy<I> {
     fn m_lt<#[lt_meth] 'h>(_: &'h [u32]) -> &'h u32 { loop { } }
-    //~^ ERROR The attribute `lt_meth` is currently unknown to the compiler
+    //~^ ERROR the attribute `lt_meth` is currently unknown to the compiler
     fn m_ty<#[ty_meth] P>(_: P) { }
-    //~^ ERROR The attribute `ty_meth` is currently unknown to the compiler
+    //~^ ERROR the attribute `ty_meth` is currently unknown to the compiler
 }
 
 fn hof_lt<Q>(_: Q)
     where Q: for <#[lt_hof] 'i> Fn(&'i [u32]) -> &'i u32
-    //~^ ERROR The attribute `lt_hof` is currently unknown to the compiler
+    //~^ ERROR the attribute `lt_hof` is currently unknown to the compiler
 {
 }
 

src/test/ui/feature-gates/feature-gate-custom_attribute2.stderr

@@ -1,4 +1,4 @@
-error[E0658]: The attribute `lt_struct` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `lt_struct` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:6:13
    |
 LL | struct StLt<#[lt_struct] 'a>(&'a u32);
@@ -7,7 +7,7 @@ LL | struct StLt<#[lt_struct] 'a>(&'a u32);
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `ty_struct` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `ty_struct` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:8:13
    |
 LL | struct StTy<#[ty_struct] I>(I);
@@ -16,7 +16,7 @@ LL | struct StTy<#[ty_struct] I>(I);
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `lt_enum` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `lt_enum` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:11:11
    |
 LL | enum EnLt<#[lt_enum] 'b> { A(&'b u32), B }
@@ -25,7 +25,7 @@ LL | enum EnLt<#[lt_enum] 'b> { A(&'b u32), B }
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `ty_enum` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `ty_enum` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:13:11
    |
 LL | enum EnTy<#[ty_enum] J> { A(J), B }
@@ -34,7 +34,7 @@ LL | enum EnTy<#[ty_enum] J> { A(J), B }
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `lt_trait` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `lt_trait` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:16:12
    |
 LL | trait TrLt<#[lt_trait] 'c> { fn foo(&self, _: &'c [u32]) -> &'c u32; }
@@ -43,7 +43,7 @@ LL | trait TrLt<#[lt_trait] 'c> { fn foo(&self, _: &'c [u32]) -> &'c u32; }
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `ty_trait` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `ty_trait` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:18:12
    |
 LL | trait TrTy<#[ty_trait] K> { fn foo(&self, _: K); }
@@ -52,7 +52,7 @@ LL | trait TrTy<#[ty_trait] K> { fn foo(&self, _: K); }
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `lt_type` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `lt_type` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:21:11
    |
 LL | type TyLt<#[lt_type] 'd> = &'d u32;
@@ -61,7 +61,7 @@ LL | type TyLt<#[lt_type] 'd> = &'d u32;
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `ty_type` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `ty_type` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:23:11
    |
 LL | type TyTy<#[ty_type] L> = (L, );
@@ -70,7 +70,7 @@ LL | type TyTy<#[ty_type] L> = (L, );
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `lt_inherent` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `lt_inherent` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:26:6
    |
 LL | impl<#[lt_inherent] 'e> StLt<'e> { }
@@ -79,7 +79,7 @@ LL | impl<#[lt_inherent] 'e> StLt<'e> { }
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `ty_inherent` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `ty_inherent` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:28:6
    |
 LL | impl<#[ty_inherent] M> StTy<M> { }
@@ -88,7 +88,7 @@ LL | impl<#[ty_inherent] M> StTy<M> { }
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `lt_impl_for` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `lt_impl_for` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:31:6
    |
 LL | impl<#[lt_impl_for] 'f> TrLt<'f> for StLt<'f> {
@@ -97,7 +97,7 @@ LL | impl<#[lt_impl_for] 'f> TrLt<'f> for StLt<'f> {
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `ty_impl_for` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `ty_impl_for` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:35:6
    |
 LL | impl<#[ty_impl_for] N> TrTy<N> for StTy<N> {
@@ -106,7 +106,7 @@ LL | impl<#[ty_impl_for] N> TrTy<N> for StTy<N> {
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `lt_fn` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `lt_fn` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:40:9
    |
 LL | fn f_lt<#[lt_fn] 'g>(_: &'g [u32]) -> &'g u32 { loop { } }
@@ -115,7 +115,7 @@ LL | fn f_lt<#[lt_fn] 'g>(_: &'g [u32]) -> &'g u32 { loop { } }
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `ty_fn` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `ty_fn` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:42:9
    |
 LL | fn f_ty<#[ty_fn] O>(_: O) { }
@@ -124,7 +124,7 @@ LL | fn f_ty<#[ty_fn] O>(_: O) { }
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `lt_meth` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `lt_meth` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:46:13
    |
 LL |     fn m_lt<#[lt_meth] 'h>(_: &'h [u32]) -> &'h u32 { loop { } }
@@ -133,7 +133,7 @@ LL |     fn m_lt<#[lt_meth] 'h>(_: &'h [u32]) -> &'h u32 { loop { } }
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `ty_meth` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `ty_meth` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:48:13
    |
 LL |     fn m_ty<#[ty_meth] P>(_: P) { }
@@ -142,7 +142,7 @@ LL |     fn m_ty<#[ty_meth] P>(_: P) { }
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `lt_hof` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `lt_hof` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/feature-gate-custom_attribute2.rs:53:19
    |
 LL |     where Q: for <#[lt_hof] 'i> Fn(&'i [u32]) -> &'i u32

src/test/ui/feature-gates/feature-gate-may-dangle.rs

@@ -4,7 +4,7 @@
 
 struct Pt<A>(A);
 unsafe impl<#[may_dangle] A> Drop for Pt<A> {
-    //~^ ERROR may_dangle has unstable semantics and may be removed in the future
+    //~^ ERROR `may_dangle` has unstable semantics and may be removed in the future
     fn drop(&mut self) { }
 }
 

src/test/ui/feature-gates/feature-gate-may-dangle.stderr

@@ -1,4 +1,4 @@
-error[E0658]: may_dangle has unstable semantics and may be removed in the future
+error[E0658]: `may_dangle` has unstable semantics and may be removed in the future
   --> $DIR/feature-gate-may-dangle.rs:6:13
    |
 LL | unsafe impl<#[may_dangle] A> Drop for Pt<A> {

src/test/ui/proc-macro/proc-macro-gates2.stderr

@@ -1,4 +1,4 @@
-error[E0658]: The attribute `empty_attr` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `empty_attr` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/proc-macro-gates2.rs:12:11
    |
 LL | fn _test6<#[empty_attr] T>() {}
@@ -7,7 +7,7 @@ LL | fn _test6<#[empty_attr] T>() {}
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(custom_attribute)]` to the crate attributes to enable
 
-error[E0658]: The attribute `empty_attr` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: the attribute `empty_attr` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/proc-macro-gates2.rs:17:9
    |
 LL |         #[empty_attr]