From d9cd0d4d1180f09ea67be012848ff295a4681961 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Tue, 6 Feb 2024 16:01:54 +0000
Subject: [PATCH] Don't expect early-bound region to be local in RPITIT
 well-formedness

---
 compiler/rustc_middle/src/ty/context.rs         |  2 +-
 .../in-trait/auxiliary/bad-region.rs            |  7 +++++++
 tests/ui/async-await/in-trait/bad-region.rs     | 17 +++++++++++++++++
 tests/ui/async-await/in-trait/bad-region.stderr | 14 ++++++++++++++
 4 files changed, 39 insertions(+), 1 deletion(-)
 create mode 100644 tests/ui/async-await/in-trait/auxiliary/bad-region.rs
 create mode 100644 tests/ui/async-await/in-trait/bad-region.rs
 create mode 100644 tests/ui/async-await/in-trait/bad-region.stderr

diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 0d53870a0baf0..70c6811e539b9 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -1193,7 +1193,7 @@ impl<'tcx> TyCtxt<'tcx> {
         let (suitable_region_binding_scope, bound_region) = loop {
             let def_id = match region.kind() {
                 ty::ReLateParam(fr) => fr.bound_region.get_id()?.as_local()?,
-                ty::ReEarlyParam(ebr) => ebr.def_id.expect_local(),
+                ty::ReEarlyParam(ebr) => ebr.def_id.as_local()?,
                 _ => return None, // not a free region
             };
             let scope = self.local_parent(def_id);
diff --git a/tests/ui/async-await/in-trait/auxiliary/bad-region.rs b/tests/ui/async-await/in-trait/auxiliary/bad-region.rs
new file mode 100644
index 0000000000000..02dc25aaa16bb
--- /dev/null
+++ b/tests/ui/async-await/in-trait/auxiliary/bad-region.rs
@@ -0,0 +1,7 @@
+// edition:2021
+
+#[allow(async_fn_in_trait)]
+
+pub trait BleRadio<'a> {
+    async fn transmit(&mut self);
+}
diff --git a/tests/ui/async-await/in-trait/bad-region.rs b/tests/ui/async-await/in-trait/bad-region.rs
new file mode 100644
index 0000000000000..444368e21a497
--- /dev/null
+++ b/tests/ui/async-await/in-trait/bad-region.rs
@@ -0,0 +1,17 @@
+// aux-build:bad-region.rs
+// edition:2021
+
+#![allow(async_fn_in_trait)]
+
+extern crate bad_region as jewel;
+
+use jewel::BleRadio;
+
+pub struct Radio {}
+
+impl BleRadio for Radio {
+//~^ ERROR implicit elided lifetime not allowed here
+    async fn transmit(&mut self) {}
+}
+
+fn main() {}
diff --git a/tests/ui/async-await/in-trait/bad-region.stderr b/tests/ui/async-await/in-trait/bad-region.stderr
new file mode 100644
index 0000000000000..9203fd790af78
--- /dev/null
+++ b/tests/ui/async-await/in-trait/bad-region.stderr
@@ -0,0 +1,14 @@
+error[E0726]: implicit elided lifetime not allowed here
+  --> $DIR/bad-region.rs:12:6
+   |
+LL | impl BleRadio for Radio {
+   |      ^^^^^^^^ expected lifetime parameter
+   |
+help: indicate the anonymous lifetime
+   |
+LL | impl BleRadio<'_> for Radio {
+   |              ++++
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0726`.