diff --git a/src/libcore/cleanup.rs b/src/libcore/cleanup.rs
index 2cf7fc92f12..3435e933ea2 100644
--- a/src/libcore/cleanup.rs
+++ b/src/libcore/cleanup.rs
@@ -1,5 +1,9 @@
 #[doc(hidden)];
 
+// NB: transitionary, de-mode-ing.
+#[forbid(deprecated_mode)];
+#[forbid(deprecated_pattern)];
+
 use libc::{c_char, c_void, intptr_t, uintptr_t};
 use ptr::{mut_null, null, to_unsafe_ptr};
 use repr::BoxRepr;
diff --git a/src/libcore/from_str.rs b/src/libcore/from_str.rs
index 6867db7c431..b9bd322a816 100644
--- a/src/libcore/from_str.rs
+++ b/src/libcore/from_str.rs
@@ -1,5 +1,9 @@
 //! The trait for types that can be created from strings
 
+// NB: transitionary, de-mode-ing.
+#[forbid(deprecated_mode)];
+#[forbid(deprecated_pattern)];
+
 use option::Option;
 
 trait FromStr {
diff --git a/src/libcore/logging.rs b/src/libcore/logging.rs
index 1e233dfe8d5..bb951c76597 100644
--- a/src/libcore/logging.rs
+++ b/src/libcore/logging.rs
@@ -1,5 +1,9 @@
 //! Logging
 
+// NB: transitionary, de-mode-ing.
+#[forbid(deprecated_mode)];
+#[forbid(deprecated_pattern)];
+
 export console_on, console_off;
 
 #[nolink]