Change feature flag error to be ergonomic clones are experimental

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -489,7 +489,7 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
     gate_all!(dyn_star, "`dyn*` trait objects are experimental");
     gate_all!(const_closures, "const closures are experimental");
     gate_all!(builtin_syntax, "`builtin #` syntax is unstable");
-    gate_all!(ergonomic_clones, "`.use` calls are experimental");
+    gate_all!(ergonomic_clones, "ergonomic clones are experimental");
     gate_all!(explicit_tail_calls, "`become` expression is experimental");
     gate_all!(generic_const_items, "generic const items are experimental");
     gate_all!(guard_patterns, "guard patterns are experimental", "consider using match arm guards");

tests/ui/ergonomic-clones/dotuse/parse.stderr

@@ -28,7 +28,7 @@ error: incorrect use of `use`
 LL |     1.use();
    |          ^^
    |
-help: `use` is not a method call, remove the parentheses
+help: `use` is not a method call, try removing the parentheses
    |
 LL -     1.use();
 LL +     1.use;

tests/ui/feature-gates/feature-gate-ergonomic-clones.rs

@@ -3,7 +3,7 @@ use std::clone::UseCloned;
 
 fn ergonomic_clone(x: i32) -> i32 {
     x.use
-    //~^ ERROR `.use` calls are experimental [E0658]
+    //~^ ERROR ergonomic clones are experimental [E0658]
 }
 
 #[derive(Clone)]
@@ -16,12 +16,12 @@ fn ergonomic_closure_clone() {
     let f1 = Foo;
 
     let f2 = use || {
-        //~^ ERROR `.use` calls are experimental [E0658]
+        //~^ ERROR ergonomic clones are experimental [E0658]
         f1
     };
 
     let f3 = use || {
-        //~^ ERROR `.use` calls are experimental [E0658]
+        //~^ ERROR ergonomic clones are experimental [E0658]
         f1
     };
 }

tests/ui/feature-gates/feature-gate-ergonomic-clones.stderr

@@ -1,4 +1,4 @@
-error[E0658]: `.use` calls are experimental
+error[E0658]: ergonomic clones are experimental
   --> $DIR/feature-gate-ergonomic-clones.rs:5:7
    |
 LL |     x.use
@@ -8,7 +8,7 @@ LL |     x.use
    = help: add `#![feature(ergonomic_clones)]` 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    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date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` calls are experimental
+error[E0658]: ergonomic clones are experimental
   --> $DIR/feature-gate-ergonomic-clones.rs:18:14
    |
 LL |     let f2 = use || {
@@ -18,7 +18,7 @@ LL |     let f2 = use || {
    = help: add `#![feature(ergonomic_clones)]` 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` calls are experimental
+error[E0658]: ergonomic clones are experimental
   --> $DIR/feature-gate-ergonomic-clones.rs:23:14
    |
 LL |     let f3 = use || {