1 files changed, 30 insertions, 0 deletions
diff --git a/src/test/ui/typeck/issue-100246.rs b/src/test/ui/typeck/issue-100246.rs
new file mode 100644
index 000000000..8f0b34bab
--- /dev/null
+++ b/src/test/ui/typeck/issue-100246.rs
@@ -0,0 +1,30 @@
+#![recursion_limit = "5"] // To reduce noise
+
+//expect incompatible type error when ambiguous traits are in scope
+//and not an overflow error on the span in the main function.
+
+struct Ratio<T>(T);
+
+pub trait Pow {
+    fn pow(self) -> Self;
+}
+
+impl<'a, T> Pow for &'a Ratio<T>
+where
+    &'a T: Pow,
+{
+    fn pow(self) -> Self {
+        self
+    }
+}
+
+fn downcast<'a, W: ?Sized>() -> std::io::Result<&'a W> {
+    todo!()
+}
+
+struct Other;
+
+fn main() -> std::io::Result<()> {
+    let other: Other = downcast()?;//~ERROR 28:24: 28:35: `?` operator has incompatible types
+    Ok(())
+}