From 788261d2d30c92c7423a68088aaee32ce44f9520 Mon Sep 17 00:00:00 2001
From: Yuki Okushi <huyuumi.dev@gmail.com>
Date: Wed, 29 Jul 2020 05:32:28 +0900
Subject: [PATCH 1/2] Add regression test for issue-59311

---
 .../ui/higher-rank-trait-bounds/issue-59311.rs   | 16 ++++++++++++++++
 .../higher-rank-trait-bounds/issue-59311.stderr  |  8 ++++++++
 2 files changed, 24 insertions(+)
 create mode 100644 src/test/ui/higher-rank-trait-bounds/issue-59311.rs
 create mode 100644 src/test/ui/higher-rank-trait-bounds/issue-59311.stderr

diff --git a/src/test/ui/higher-rank-trait-bounds/issue-59311.rs b/src/test/ui/higher-rank-trait-bounds/issue-59311.rs
new file mode 100644
index 0000000000000..c2168510cf5b8
--- /dev/null
+++ b/src/test/ui/higher-rank-trait-bounds/issue-59311.rs
@@ -0,0 +1,16 @@
+// Regression test for #59311. The test is taken from
+// rust-lang/rust/issues/71546#issuecomment-620638437
+// as they seem to have the same cause.
+
+pub trait T {
+    fn t<F: Fn()>(&self, _: F) {}
+}
+
+pub fn crash<V>(v: &V)
+where
+    for<'a> &'a V: T + 'static,
+{
+    v.t(|| {}); //~ ERROR: higher-ranked subtype error
+}
+
+fn main() {}
diff --git a/src/test/ui/higher-rank-trait-bounds/issue-59311.stderr b/src/test/ui/higher-rank-trait-bounds/issue-59311.stderr
new file mode 100644
index 0000000000000..e6488c337114b
--- /dev/null
+++ b/src/test/ui/higher-rank-trait-bounds/issue-59311.stderr
@@ -0,0 +1,8 @@
+error: higher-ranked subtype error
+  --> $DIR/issue-59311.rs:13:9
+   |
+LL |     v.t(|| {});
+   |         ^^^^^
+
+error: aborting due to previous error
+

From cc36c3d140b82757c5ffe94c71232d2f32fcf2a4 Mon Sep 17 00:00:00 2001
From: Yuki Okushi <huyuumi.dev@gmail.com>
Date: Thu, 6 Aug 2020 05:21:03 +0900
Subject: [PATCH 2/2] Add a FIXME comment

---
 src/test/ui/higher-rank-trait-bounds/issue-59311.rs     | 4 ++++
 src/test/ui/higher-rank-trait-bounds/issue-59311.stderr | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/test/ui/higher-rank-trait-bounds/issue-59311.rs b/src/test/ui/higher-rank-trait-bounds/issue-59311.rs
index c2168510cf5b8..1e1241c7f83c5 100644
--- a/src/test/ui/higher-rank-trait-bounds/issue-59311.rs
+++ b/src/test/ui/higher-rank-trait-bounds/issue-59311.rs
@@ -2,6 +2,10 @@
 // rust-lang/rust/issues/71546#issuecomment-620638437
 // as they seem to have the same cause.
 
+// FIXME: It's not clear that this code ought to report
+// an error, but the regression test is here to ensure
+// that it does not ICE. See discussion on #74889 for details.
+
 pub trait T {
     fn t<F: Fn()>(&self, _: F) {}
 }
diff --git a/src/test/ui/higher-rank-trait-bounds/issue-59311.stderr b/src/test/ui/higher-rank-trait-bounds/issue-59311.stderr
index e6488c337114b..ca6326292672b 100644
--- a/src/test/ui/higher-rank-trait-bounds/issue-59311.stderr
+++ b/src/test/ui/higher-rank-trait-bounds/issue-59311.stderr
@@ -1,5 +1,5 @@
 error: higher-ranked subtype error
-  --> $DIR/issue-59311.rs:13:9
+  --> $DIR/issue-59311.rs:17:9
    |
 LL |     v.t(|| {});
    |         ^^^^^