1 files changed, 18 insertions, 0 deletions
diff --git a/tests/ui/rust-2021/generic-type-collision.rs b/tests/ui/rust-2021/generic-type-collision.rs
new file mode 100644
index 000000000..335e7e520
--- /dev/null
+++ b/tests/ui/rust-2021/generic-type-collision.rs
@@ -0,0 +1,18 @@
+// check-pass
+// run-rustfix
+// edition 2018
+#![warn(rust_2021_prelude_collisions)]
+
+trait MyTrait<A> {
+    fn from_iter(x: Option<A>);
+}
+
+impl<T> MyTrait<()> for Vec<T> {
+    fn from_iter(_: Option<()>) {}
+}
+
+fn main() {
+    <Vec<i32>>::from_iter(None);
+    //~^ WARNING trait-associated function `from_iter` will become ambiguous in Rust 2021
+    //~^^ WARNING this is accepted in the current edition
+}