1 files changed, 47 insertions, 0 deletions

diff --git a/tests/ui/parser/issues/issue-57819.rs b/tests/ui/parser/issues/issue-57819.rs
new file mode 100644
index 00000000000..5cafbf439be
--- /dev/null
+++ b/tests/ui/parser/issues/issue-57819.rs
@@ -0,0 +1,47 @@
+// run-rustfix
+
+#![allow(warnings)]
+
+// This test checks that the following error is emitted and the suggestion works:
+//
+// ```
+// let _ = vec![1, 2, 3].into_iter().collect::<<<Vec<usize>>();
+//                                            ^^ help: remove extra angle brackets
+// ```
+
+trait Foo {
+    type Output;
+}
+
+fn foo<T: Foo>() {
+    // More complex cases with more than one correct leading `<` character:
+
+    bar::<<<<<T as Foo>::Output>();
+    //~^ ERROR unmatched angle bracket
+
+    bar::<<<<T as Foo>::Output>();
+    //~^ ERROR unmatched angle bracket
+
+    bar::<<<T as Foo>::Output>();
+    //~^ ERROR unmatched angle bracket
+
+    bar::<<T as Foo>::Output>();
+}
+
+fn bar<T>() {}
+
+fn main() {
+    let _ = vec![1, 2, 3].into_iter().collect::<<<<<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<<<<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<<<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>();
+}