Add regression test

tests/ui/consts/drop-impl-nonconst-drop-field.rs

@@ -0,0 +1,31 @@
+#![feature(const_trait_impl)]
+#![feature(const_destruct)]
+//@ check-pass
+
+use std::marker::Destruct;
+
+struct NotConstDrop;
+
+impl Drop for NotConstDrop {
+    fn drop(&mut self) {}
+}
+
+struct ConstDrop(NotConstDrop);
+
+impl const Drop for ConstDrop {
+    fn drop(&mut self) {}
+}
+
+struct ConstDrop2<T>(T);
+
+impl<T> const Drop for ConstDrop2<T> {
+    fn drop(&mut self) {}
+}
+
+struct ConstDrop3<T>(T);
+
+impl<T: [const] Destruct> const Drop for ConstDrop3<T> {
+    fn drop(&mut self) {}
+}
+
+fn main() {}