1 files changed, 38 insertions, 0 deletions
diff --git a/compiler/rustc_error_codes/src/error_codes/E0120.md b/compiler/rustc_error_codes/src/error_codes/E0120.md
new file mode 100644
index 000000000..dc7258d87
--- /dev/null
+++ b/compiler/rustc_error_codes/src/error_codes/E0120.md
@@ -0,0 +1,38 @@
+Drop was implemented on a trait, which is not allowed: only structs and
+enums can implement Drop.
+
+Erroneous code example:
+
+```compile_fail,E0120
+trait MyTrait {}
+
+impl Drop for MyTrait {
+    fn drop(&mut self) {}
+}
+```
+
+A workaround for this problem is to wrap the trait up in a struct, and implement
+Drop on that:
+
+```
+trait MyTrait {}
+struct MyWrapper<T: MyTrait> { foo: T }
+
+impl <T: MyTrait> Drop for MyWrapper<T> {
+    fn drop(&mut self) {}
+}
+
+```
+
+Alternatively, wrapping trait objects requires something:
+
+```
+trait MyTrait {}
+
+//or Box<MyTrait>, if you wanted an owned trait object
+struct MyWrapper<'a> { foo: &'a MyTrait }
+
+impl <'a> Drop for MyWrapper<'a> {
+    fn drop(&mut self) {}
+}
+```