diff --git a/src/librustc/middle/stability.rs b/src/librustc/middle/stability.rs
index 36bdca8c8e9..0a0f555f977 100644
--- a/src/librustc/middle/stability.rs
+++ b/src/librustc/middle/stability.rs
@@ -261,12 +261,12 @@ fn check(&mut self, id: ast::DefId, span: Span, stab: &Option<Stability>) {
                 if self.tcx.sess.features.borrow().unmarked_api {
                     self.tcx.sess.span_warn(span, "use of unmarked library feature");
                     self.tcx.sess.span_note(span, "this is either a bug in the library you are \
-                                                   using and a bug in the compiler - please \
+                                                   using or a bug in the compiler - please \
                                                    report it in both places");
                 } else {
                     self.tcx.sess.span_err(span, "use of unmarked library feature");
                     self.tcx.sess.span_note(span, "this is either a bug in the library you are \
-                                                   using and a bug in the compiler - please \
+                                                   using or a bug in the compiler - please \
                                                    report it in both places");
                     self.tcx.sess.span_note(span, "use #![feature(unmarked_api)] in the \
                                                    crate attributes to override this");