forbid `dyn Trait` in const generics

2 files changed, 32 insertions, 0 deletions

diff --git a/src/test/ui/const-generics/issues/issue-63322-forbid-dyn.rs b/src/test/ui/const-generics/issues/issue-63322-forbid-dyn.rs
new file mode 100644
index 00000000000..2bacd6c9a9c
--- /dev/null
+++ b/src/test/ui/const-generics/issues/issue-63322-forbid-dyn.rs
@@ -0,0 +1,15 @@
+#![feature(const_generics)]
+//~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash
+
+trait A {}
+struct B;
+impl A for B {}
+
+fn test<const T: &'static dyn A>() {
+    //~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]` to be used
+    unimplemented!()
+}
+
+fn main() {
+    test::<{ &B }>();
+}
diff --git a/src/test/ui/const-generics/issues/issue-63322-forbid-dyn.stderr b/src/test/ui/const-generics/issues/issue-63322-forbid-dyn.stderr
new file mode 100644
index 00000000000..73315af4483
--- /dev/null
+++ b/src/test/ui/const-generics/issues/issue-63322-forbid-dyn.stderr
@@ -0,0 +1,17 @@
+warning: the feature `const_generics` is incomplete and may cause the compiler to crash
+  --> $DIR/issue-63322-forbid-dyn.rs:1:12
+   |
+LL | #![feature(const_generics)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+
+error[E0741]: `&'static (dyn A + 'static)` must be annotated with `#[derive(PartialEq, Eq)]` to be used as the type of a const parameter
+  --> $DIR/issue-63322-forbid-dyn.rs:8:18
+   |
+LL | fn test<const T: &'static dyn A>() {
+   |                  ^^^^^^^^^^^^^^ `&'static (dyn A + 'static)` doesn't derive both `PartialEq` and `Eq`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0741`.