From 00f22771f6fb625fd66122fded49d5bee7083707 Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Thu, 23 Jun 2022 19:12:13 +0400
Subject: [PATCH] Add even more tests for `impl Fn() -> impl Trait`

---
 src/test/ui/impl-trait/impl-fn-hrtb-bounds.rs | 10 ++++++
 .../ui/impl-trait/impl-fn-hrtb-bounds.stderr  | 32 ++++++++++++++++++-
 .../impl-fn-predefined-lifetimes.rs           | 12 +++++++
 3 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 src/test/ui/impl-trait/impl-fn-predefined-lifetimes.rs

diff --git a/src/test/ui/impl-trait/impl-fn-hrtb-bounds.rs b/src/test/ui/impl-trait/impl-fn-hrtb-bounds.rs
index f7d9430a2263..25144c090485 100644
--- a/src/test/ui/impl-trait/impl-fn-hrtb-bounds.rs
+++ b/src/test/ui/impl-trait/impl-fn-hrtb-bounds.rs
@@ -10,4 +10,14 @@ fn b() -> impl for<'a> Fn(&'a u8) -> (impl Debug + 'a) {
     |x| x
 }
 
+fn c() -> impl for<'a> Fn(&'a u8) -> (impl Debug + '_) {
+    //~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+    |x| x
+}
+
+fn d() -> impl Fn() -> (impl Debug + '_) {
+    //~^ ERROR missing lifetime specifier
+    || ()
+}
+
 fn main() {}
diff --git a/src/test/ui/impl-trait/impl-fn-hrtb-bounds.stderr b/src/test/ui/impl-trait/impl-fn-hrtb-bounds.stderr
index 6fe4534d9281..6985c66df879 100644
--- a/src/test/ui/impl-trait/impl-fn-hrtb-bounds.stderr
+++ b/src/test/ui/impl-trait/impl-fn-hrtb-bounds.stderr
@@ -22,5 +22,35 @@ note: lifetime declared here
 LL | fn b() -> impl for<'a> Fn(&'a u8) -> (impl Debug + 'a) {
    |                    ^^
 
-error: aborting due to 2 previous errors
+error: higher kinded lifetime bounds on nested opaque types are not supported yet
+  --> $DIR/impl-fn-hrtb-bounds.rs:13:52
+   |
+LL | fn c() -> impl for<'a> Fn(&'a u8) -> (impl Debug + '_) {
+   |                                                    ^^
+   |
+note: lifetime declared here
+  --> $DIR/impl-fn-hrtb-bounds.rs:13:20
+   |
+LL | fn c() -> impl for<'a> Fn(&'a u8) -> (impl Debug + '_) {
+   |                    ^^
 
+error[E0106]: missing lifetime specifier
+  --> $DIR/impl-fn-hrtb-bounds.rs:18:38
+   |
+LL | fn d() -> impl Fn() -> (impl Debug + '_) {
+   |                                      ^^ expected named lifetime parameter
+   |
+   = help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from
+   = note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html
+help: consider making the bound lifetime-generic with a new `'a` lifetime
+   |
+LL | fn d() -> impl for<'a> Fn() -> (impl Debug + 'a) {
+   |                +++++++                       ~~
+help: consider using the `'static` lifetime
+   |
+LL | fn d() -> impl Fn() -> (impl Debug + 'static) {
+   |                                      ~~~~~~~
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0106`.
diff --git a/src/test/ui/impl-trait/impl-fn-predefined-lifetimes.rs b/src/test/ui/impl-trait/impl-fn-predefined-lifetimes.rs
new file mode 100644
index 000000000000..e2f6e600da43
--- /dev/null
+++ b/src/test/ui/impl-trait/impl-fn-predefined-lifetimes.rs
@@ -0,0 +1,12 @@
+// check-pass
+use std::fmt::Debug;
+
+fn a<'a>() -> impl Fn(&'a u8) -> (impl Debug + '_) {
+    |x| x
+}
+
+fn _b<'a>() -> impl Fn(&'a u8) -> (impl Debug + 'a) {
+    a()
+}
+
+fn main() {}