From 3f2574e8bad436a01a2cb7ea1b054f457bba5f0d Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Fri, 13 Oct 2023 19:47:40 +0000
Subject: [PATCH] Test that RPITITs have RPIT scope and not impl-wide scope

---
 .../in-trait/sibling-function-constraint.rs   | 21 +++++++++++++++++++
 .../sibling-function-constraint.stderr        | 17 +++++++++++++++
 2 files changed, 38 insertions(+)
 create mode 100644 tests/ui/impl-trait/in-trait/sibling-function-constraint.rs
 create mode 100644 tests/ui/impl-trait/in-trait/sibling-function-constraint.stderr

diff --git a/tests/ui/impl-trait/in-trait/sibling-function-constraint.rs b/tests/ui/impl-trait/in-trait/sibling-function-constraint.rs
new file mode 100644
index 00000000000..fe162e6cf80
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/sibling-function-constraint.rs
@@ -0,0 +1,21 @@
+// Checks that a sibling function (i.e. `foo`) cannot constrain
+// an RPITIT from another function (`bar`).
+
+trait Trait {
+    fn foo();
+
+    fn bar() -> impl Sized;
+}
+
+impl Trait for () {
+    fn foo() {
+        let _: String = Self::bar();
+        //~^ ERROR mismatched types
+    }
+
+    fn bar() -> impl Sized {
+        loop {}
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/impl-trait/in-trait/sibling-function-constraint.stderr b/tests/ui/impl-trait/in-trait/sibling-function-constraint.stderr
new file mode 100644
index 00000000000..729963a8141
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/sibling-function-constraint.stderr
@@ -0,0 +1,17 @@
+error[E0308]: mismatched types
+  --> $DIR/sibling-function-constraint.rs:12:25
+   |
+LL |         let _: String = Self::bar();
+   |                ------   ^^^^^^^^^^^ expected `String`, found opaque type
+   |                |
+   |                expected due to this
+...
+LL |     fn bar() -> impl Sized {
+   |                 ---------- the found opaque type
+   |
+   = note:   expected struct `String`
+           found opaque type `impl Sized`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.