From 64d98f8ee037282c35007b64c2649055c56af1db Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 17 Apr 2024 14:19:03 +0200
Subject: Merging upstream version 1.68.2+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 tests/ui/impl-trait/negative-reasoning.rs | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 tests/ui/impl-trait/negative-reasoning.rs

(limited to 'tests/ui/impl-trait/negative-reasoning.rs')

diff --git a/tests/ui/impl-trait/negative-reasoning.rs b/tests/ui/impl-trait/negative-reasoning.rs
new file mode 100644
index 000000000..70e24a3a9
--- /dev/null
+++ b/tests/ui/impl-trait/negative-reasoning.rs
@@ -0,0 +1,23 @@
+// Tests that we cannot assume that an opaque type does *not* implement some
+// other trait
+#![feature(type_alias_impl_trait)]
+
+trait OpaqueTrait {}
+impl<T> OpaqueTrait for T {}
+type OpaqueType = impl OpaqueTrait;
+fn mk_opaque() -> OpaqueType {
+    ()
+}
+
+#[derive(Debug)]
+struct D<T>(T);
+
+trait AnotherTrait {}
+impl<T: std::fmt::Debug> AnotherTrait for T {}
+
+// This is in error, because we cannot assume that `OpaqueType: !Debug`
+impl AnotherTrait for D<OpaqueType> {
+    //~^ ERROR conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>`
+}
+
+fn main() {}
-- 
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