From 3bf9eb0f7a1f2da9df2983aa8cf95a420130cada Mon Sep 17 00:00:00 2001
From: XIAO Tian <tian@example.com>
Date: Sat, 30 May 2020 11:28:33 +0800
Subject: [PATCH] Add a test for wrong assoc type diagnostics

---
 src/test/ui/associated-types/issue-72806.rs   | 20 +++++++++++++++++++
 .../ui/associated-types/issue-72806.stderr    |  9 +++++++++
 2 files changed, 29 insertions(+)
 create mode 100644 src/test/ui/associated-types/issue-72806.rs
 create mode 100644 src/test/ui/associated-types/issue-72806.stderr

diff --git a/src/test/ui/associated-types/issue-72806.rs b/src/test/ui/associated-types/issue-72806.rs
new file mode 100644
index 000000000000..ae63781d568a
--- /dev/null
+++ b/src/test/ui/associated-types/issue-72806.rs
@@ -0,0 +1,20 @@
+trait Bar {
+    type Ok;
+    type Sibling: Bar2<Ok=char>;
+}
+trait Bar2 {
+    type Ok;
+}
+
+struct Foo;
+struct Foo2;
+
+impl Bar for Foo {  //~ ERROR type mismatch resolving `<Foo2 as Bar2>::Ok == char`
+    type Ok = ();
+    type Sibling = Foo2;
+}
+impl Bar2 for Foo2 {
+    type Ok = u32;
+}
+
+fn main() {}
diff --git a/src/test/ui/associated-types/issue-72806.stderr b/src/test/ui/associated-types/issue-72806.stderr
new file mode 100644
index 000000000000..03a6565848dc
--- /dev/null
+++ b/src/test/ui/associated-types/issue-72806.stderr
@@ -0,0 +1,9 @@
+error[E0271]: type mismatch resolving `<Foo2 as Bar2>::Ok == char`
+  --> $DIR/issue-72806.rs:12:6
+   |
+LL | impl Bar for Foo {
+   |      ^^^ expected `u32`, found `char`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0271`.