From 5eb0528483ddb7614578fe5ef4b1104047b10ce6 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Tue, 11 Apr 2023 17:17:25 +0000
Subject: Erase lifetimes above ty::INNERMOST when probing ambiguous types

---
 .../ui/traits/non_lifetime_binders/missing-assoc-item.stderr |  7 ++++++-
 tests/ui/typeck/issue-110052.rs                              | 12 ++++++++++++
 tests/ui/typeck/issue-110052.stderr                          |  9 +++++++++
 3 files changed, 27 insertions(+), 1 deletion(-)
 create mode 100644 tests/ui/typeck/issue-110052.rs
 create mode 100644 tests/ui/typeck/issue-110052.stderr

(limited to 'tests')

diff --git a/tests/ui/traits/non_lifetime_binders/missing-assoc-item.stderr b/tests/ui/traits/non_lifetime_binders/missing-assoc-item.stderr
index be6955c111e..d985386423d 100644
--- a/tests/ui/traits/non_lifetime_binders/missing-assoc-item.stderr
+++ b/tests/ui/traits/non_lifetime_binders/missing-assoc-item.stderr
@@ -11,7 +11,12 @@ error[E0223]: ambiguous associated type
   --> $DIR/missing-assoc-item.rs:6:12
    |
 LL |     for<B> B::Item: Send,
-   |            ^^^^^^^ help: use the fully-qualified path: `<B as IntoIterator>::Item`
+   |            ^^^^^^^
+   |
+help: if there were a trait named `Example` with associated type `Item` implemented for `B`, you could use the fully-qualified path
+   |
+LL |     for<B> <B as Example>::Item: Send,
+   |            ~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to previous error; 1 warning emitted
 
diff --git a/tests/ui/typeck/issue-110052.rs b/tests/ui/typeck/issue-110052.rs
new file mode 100644
index 00000000000..f124b58b5b6
--- /dev/null
+++ b/tests/ui/typeck/issue-110052.rs
@@ -0,0 +1,12 @@
+// Makes sure we deal with escaping lifetimes *above* INNERMOST when
+// suggesting trait for ambiguous associated type.
+
+impl<I, V> Validator<I> for ()
+where
+    for<'iter> dyn Validator<<&'iter I>::Item>:,
+    //~^ ERROR ambiguous associated type
+{}
+
+pub trait Validator<T> {}
+
+fn main() {}
diff --git a/tests/ui/typeck/issue-110052.stderr b/tests/ui/typeck/issue-110052.stderr
new file mode 100644
index 00000000000..0c15c03a740
--- /dev/null
+++ b/tests/ui/typeck/issue-110052.stderr
@@ -0,0 +1,9 @@
+error[E0223]: ambiguous associated type
+  --> $DIR/issue-110052.rs:6:30
+   |
+LL |     for<'iter> dyn Validator<<&'iter I>::Item>:,
+   |                              ^^^^^^^^^^^^^^^^ help: use the fully-qualified path: `<&'iter I as IntoIterator>::Item`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0223`.
-- 
cgit 1.4.1-3-g733a5