From 75afb22331daececeba38a3efb0134348d6c14d9 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Wed, 16 Nov 2022 22:21:41 +0000
Subject: [PATCH] Check `dyn*` return type correctly

---
 compiler/rustc_hir_typeck/src/check.rs |  2 +-
 src/test/ui/dyn-star/return.rs         | 10 ++++++++++
 src/test/ui/dyn-star/return.stderr     | 11 +++++++++++
 3 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 src/test/ui/dyn-star/return.rs
 create mode 100644 src/test/ui/dyn-star/return.stderr

diff --git a/compiler/rustc_hir_typeck/src/check.rs b/compiler/rustc_hir_typeck/src/check.rs
index 3c57e33f6f7fb..296cf00a687c7 100644
--- a/compiler/rustc_hir_typeck/src/check.rs
+++ b/compiler/rustc_hir_typeck/src/check.rs
@@ -100,7 +100,7 @@ pub(super) fn check_fn<'a, 'tcx>(
 
     inherited.typeck_results.borrow_mut().liberated_fn_sigs_mut().insert(fn_id, fn_sig);
 
-    if let ty::Dynamic(..) = declared_ret_ty.kind() {
+    if let ty::Dynamic(_, _, ty::Dyn) = declared_ret_ty.kind() {
         // FIXME: We need to verify that the return type is `Sized` after the return expression has
         // been evaluated so that we have types available for all the nodes being returned, but that
         // requires the coerced evaluated type to be stored. Moving `check_return_expr` before this
diff --git a/src/test/ui/dyn-star/return.rs b/src/test/ui/dyn-star/return.rs
new file mode 100644
index 0000000000000..fa3d8d7d5064c
--- /dev/null
+++ b/src/test/ui/dyn-star/return.rs
@@ -0,0 +1,10 @@
+// check-pass
+
+#![feature(dyn_star)]
+//~^ WARN the feature `dyn_star` is incomplete and may not be safe to use and/or cause compiler crashes
+
+fn _foo() -> dyn* Unpin {
+    4usize
+}
+
+fn main() {}
diff --git a/src/test/ui/dyn-star/return.stderr b/src/test/ui/dyn-star/return.stderr
new file mode 100644
index 0000000000000..e000351a68f54
--- /dev/null
+++ b/src/test/ui/dyn-star/return.stderr
@@ -0,0 +1,11 @@
+warning: the feature `dyn_star` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/return.rs:3:12
+   |
+LL | #![feature(dyn_star)]
+   |            ^^^^^^^^
+   |
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+warning: 1 warning emitted
+