From ce6658818da9844d7adb85a573952ba081b466ac Mon Sep 17 00:00:00 2001
From: JohnTitor <jtitor@2k36.org>
Date: Wed, 31 Mar 2021 18:48:28 +0900
Subject: [PATCH] Add a regression test for issue-68830

---
 .../issue-68830-spurious-diagnostics.rs       | 23 +++++++++++++++++++
 .../issue-68830-spurious-diagnostics.stderr   |  9 ++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 src/test/ui/specialization/issue-68830-spurious-diagnostics.rs
 create mode 100644 src/test/ui/specialization/issue-68830-spurious-diagnostics.stderr

diff --git a/src/test/ui/specialization/issue-68830-spurious-diagnostics.rs b/src/test/ui/specialization/issue-68830-spurious-diagnostics.rs
new file mode 100644
index 0000000000000..d11ec79833217
--- /dev/null
+++ b/src/test/ui/specialization/issue-68830-spurious-diagnostics.rs
@@ -0,0 +1,23 @@
+// A regression test for #68830. This checks we don't emit
+// a verbose `conflicting implementations` error.
+
+#![feature(specialization)]
+#![allow(incomplete_features)]
+
+struct BadStruct {
+    err: MissingType //~ ERROR: cannot find type `MissingType` in this scope
+}
+
+trait MyTrait<T> {
+    fn foo();
+}
+
+impl<T, D> MyTrait<T> for D {
+    default fn foo() {}
+}
+
+impl<T> MyTrait<T> for BadStruct {
+    fn foo() {}
+}
+
+fn main() {}
diff --git a/src/test/ui/specialization/issue-68830-spurious-diagnostics.stderr b/src/test/ui/specialization/issue-68830-spurious-diagnostics.stderr
new file mode 100644
index 0000000000000..833f61dca8cac
--- /dev/null
+++ b/src/test/ui/specialization/issue-68830-spurious-diagnostics.stderr
@@ -0,0 +1,9 @@
+error[E0412]: cannot find type `MissingType` in this scope
+  --> $DIR/issue-68830-spurious-diagnostics.rs:8:10
+   |
+LL |     err: MissingType
+   |          ^^^^^^^^^^^ not found in this scope
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0412`.