diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index 9d5189cfd0b1..68909b958ba7 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -657,6 +657,9 @@ impl fmt::Display for UnsafetySpace {
 
 impl fmt::Display for ConstnessSpace {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        if option_env!("CFG_DISABLE_UNSTABLE_FEATURES").is_some() {
+            return Ok(());
+        }
         match self.get() {
             hir::Constness::Const => write!(f, "const "),
             hir::Constness::NotConst => Ok(())