1 files changed, 20 insertions, 0 deletions

diff --git a/tests/ui/issues/issue-21763.stderr b/tests/ui/issues/issue-21763.stderr
new file mode 100644
index 000000000..04379f07b
--- /dev/null
+++ b/tests/ui/issues/issue-21763.stderr
@@ -0,0 +1,20 @@
+error[E0277]: `Rc<()>` cannot be sent between threads safely
+  --> $DIR/issue-21763.rs:9:11
+   |
+LL |     foo::<HashMap<Rc<()>, Rc<()>>>();
+   |           ^^^^^^^^^^^^^^^^^^^^^^^ `Rc<()>` cannot be sent between threads safely
+   |
+   = help: within `(Rc<()>, Rc<()>)`, the trait `Send` is not implemented for `Rc<()>`
+   = note: required because it appears within the type `(Rc<()>, Rc<()>)`
+   = note: required for `hashbrown::raw::RawTable<(Rc<()>, Rc<()>)>` to implement `Send`
+   = note: required because it appears within the type `HashMap<Rc<()>, Rc<()>, RandomState>`
+   = note: required because it appears within the type `HashMap<Rc<()>, Rc<()>>`
+note: required by a bound in `foo`
+  --> $DIR/issue-21763.rs:6:11
+   |
+LL | fn foo<T: Send>() {}
+   |           ^^^^ required by this bound in `foo`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.