From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 17 Apr 2024 14:02:58 +0200
Subject: Adding upstream version 1.64.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 .../associated-types-impl-redirect.rs              | 51 ++++++++++++++++++++++
 1 file changed, 51 insertions(+)
 create mode 100644 src/test/ui/associated-types/associated-types-impl-redirect.rs

(limited to 'src/test/ui/associated-types/associated-types-impl-redirect.rs')

diff --git a/src/test/ui/associated-types/associated-types-impl-redirect.rs b/src/test/ui/associated-types/associated-types-impl-redirect.rs
new file mode 100644
index 000000000..8fa20cdf4
--- /dev/null
+++ b/src/test/ui/associated-types/associated-types-impl-redirect.rs
@@ -0,0 +1,51 @@
+// run-pass
+#![allow(dead_code)]
+#![allow(unused_mut)]
+#![allow(unused_imports)]
+// Test how resolving a projection interacts with inference.  In this
+// case, we were eagerly unifying the type variable for the iterator
+// type with `I` from the where clause, ignoring the in-scope `impl`
+// for `ByRef`. The right answer was to consider the result ambiguous
+// until more type information was available.
+
+#![feature(lang_items)]
+#![no_implicit_prelude]
+
+use std::marker::Sized;
+use std::option::Option::{None, Some, self};
+
+trait Iterator {
+    type Item;
+
+    fn next(&mut self) -> Option<Self::Item>;
+}
+
+trait IteratorExt: Iterator + Sized {
+    fn by_ref(&mut self) -> ByRef<Self> {
+        ByRef(self)
+    }
+}
+
+impl<I> IteratorExt for I where I: Iterator {}
+
+struct ByRef<'a, I: 'a + Iterator>(&'a mut I);
+
+impl<'a, I: Iterator> Iterator for ByRef<'a, I> {
+    type Item = I::Item;
+
+    fn next(&mut self) -> Option< <I as Iterator>::Item > {
+        self.0.next()
+    }
+}
+
+fn is_iterator_of<A, I: Iterator<Item=A>>(_: &I) {}
+
+fn test<A, I: Iterator<Item=A>>(mut it: I) {
+    is_iterator_of::<A, _>(&it.by_ref());
+}
+
+fn test2<A, I1: Iterator<Item=A>, I2: Iterator<Item=I1::Item>>(mut it: I2) {
+    is_iterator_of::<A, _>(&it)
+}
+
+fn main() { }
-- 
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