Add FAQ for NLL migration

[rust.git] / src / librustc_mir / borrow_check / mod.rs

diff --git a/src/librustc_mir/borrow_check/mod.rs b/src/librustc_mir/borrow_check/mod.rs
index fc1f5eb5d5a7a45a85db4fbf4d5a55a3a3216ae8..cf02878ec82ed28db372f7877d2b2c1626c9781c 100644 (file)
--- a/src/librustc_mir/borrow_check/mod.rs
+++ b/src/librustc_mir/borrow_check/mod.rs
@@ -439,10 +439,11 @@ fn downgrade_if_error(diag: &mut Diagnostic) {
         diag.warn(
             "this error has been downgraded to a warning for backwards \
             compatibility with previous releases",
-        );
-        diag.warn(
+        ).warn(
             "this represents potential undefined behavior in your code and \
             this warning will become a hard error in the future",
+        ).note(
+            "for more information, try `rustc --explain E0729`"
         );
     }
 }