1 files changed, 51 insertions, 0 deletions

diff --git a/src/test/ui/issues/issue-86756.stderr b/src/test/ui/issues/issue-86756.stderr
new file mode 100644
index 000000000..399c940ca
--- /dev/null
+++ b/src/test/ui/issues/issue-86756.stderr
@@ -0,0 +1,51 @@
+error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
+  --> $DIR/issue-86756.rs:1:14
+   |
+LL | trait Foo<T, T = T> {}
+   |           -  ^ already used
+   |           |
+   |           first use of `T`
+
+error[E0412]: cannot find type `dyn` in this scope
+  --> $DIR/issue-86756.rs:5:10
+   |
+LL | fn eq<A, B>() {
+   |           - help: you might be missing a type parameter: `, dyn`
+LL |     eq::<dyn, Foo>
+   |          ^^^ not found in this scope
+
+warning: trait objects without an explicit `dyn` are deprecated
+  --> $DIR/issue-86756.rs:5:15
+   |
+LL |     eq::<dyn, Foo>
+   |               ^^^
+   |
+   = note: `#[warn(bare_trait_objects)]` on by default
+   = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
+help: use `dyn`
+   |
+LL -     eq::<dyn, Foo>
+LL +     eq::<dyn, dyn Foo>
+   |
+
+error[E0107]: missing generics for trait `Foo`
+  --> $DIR/issue-86756.rs:5:15
+   |
+LL |     eq::<dyn, Foo>
+   |               ^^^ expected at least 1 generic argument
+   |
+note: trait defined here, with at least 1 generic parameter: `T`
+  --> $DIR/issue-86756.rs:1:7
+   |
+LL | trait Foo<T, T = T> {}
+   |       ^^^ -
+help: add missing generic argument
+   |
+LL |     eq::<dyn, Foo<T>>
+   |               ~~~~~~
+
+error: aborting due to 3 previous errors; 1 warning emitted
+
+Some errors have detailed explanations: E0107, E0403, E0412.
+For more information about an error, try `rustc --explain E0107`.