Rollup merge of #88657 - camelid:fix-dyn-sugg, r=m-ou-se

Fix 2021 `dyn` suggestion that used code as label

The arguments to `span_suggestion` were in the wrong order, so the error
looked like this:

    error[E0783]: trait objects without an explicit `dyn` are deprecated
      --> src/test/ui/editions/dyn-trait-sugg-2021.rs:10:5
       |
    10 |     Foo::hi(123);
       |     ^^^ help: <dyn Foo>: `use `dyn``

Now the error looks like this, as expected:

    error[E0783]: trait objects without an explicit `dyn` are deprecated
      --> src/test/ui/editions/dyn-trait-sugg-2021.rs:10:5
       |
    10 |     Foo::hi(123);
       |     ^^^ help: use `dyn`: `<dyn Foo>`

This issue was only present in the 2021 error; the 2018 lint was
correct.

r? `@m-ou-se`

2 files changed, 21 insertions, 0 deletions

diff --git a/src/test/ui/editions/dyn-trait-sugg-2021.rs b/src/test/ui/editions/dyn-trait-sugg-2021.rs
new file mode 100644
index 00000000000..47c48e7ec9e
--- /dev/null
+++ b/src/test/ui/editions/dyn-trait-sugg-2021.rs
@@ -0,0 +1,12 @@
+// edition:2021
+
+trait Foo<T> {}
+
+impl<T> dyn Foo<T> {
+    fn hi(_x: T)  {}
+}
+
+fn main() {
+    Foo::hi(123);
+    //~^ ERROR trait objects without an explicit `dyn` are deprecated
+}
diff --git a/src/test/ui/editions/dyn-trait-sugg-2021.stderr b/src/test/ui/editions/dyn-trait-sugg-2021.stderr
new file mode 100644
index 00000000000..f6e9fa96a15
--- /dev/null
+++ b/src/test/ui/editions/dyn-trait-sugg-2021.stderr
@@ -0,0 +1,9 @@
+error[E0783]: trait objects without an explicit `dyn` are deprecated
+  --> $DIR/dyn-trait-sugg-2021.rs:10:5
+   |
+LL |     Foo::hi(123);
+   |     ^^^ help: use `dyn`: `<dyn Foo>`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0783`.