diff --git a/src/libcore/fmt/mod.rs b/src/libcore/fmt/mod.rs
index 65aacb23bd768..6c8a1c3062b00 100644
--- a/src/libcore/fmt/mod.rs
+++ b/src/libcore/fmt/mod.rs
@@ -1586,6 +1586,7 @@ impl Display for ! {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Debug for bool {
+    #[inline]
     fn fmt(&self, f: &mut Formatter) -> Result {
         Display::fmt(self, f)
     }
@@ -1748,6 +1749,7 @@ impl<T: Debug> Debug for [T] {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Debug for () {
+    #[inline]
     fn fmt(&self, f: &mut Formatter) -> Result {
         f.pad("()")
     }
diff --git a/src/libcore/fmt/num.rs b/src/libcore/fmt/num.rs
index ee989854a3772..2992e7cf8db34 100644
--- a/src/libcore/fmt/num.rs
+++ b/src/libcore/fmt/num.rs
@@ -157,6 +157,7 @@ macro_rules! debug {
     ($T:ident) => {
         #[stable(feature = "rust1", since = "1.0.0")]
         impl fmt::Debug for $T {
+            #[inline]
             fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
                 fmt::Display::fmt(self, f)
             }