Fix warning when compilin libcore on 16bit targets.

Fixes #49617

diff --git a/src/libcore/iter/range.rs b/src/libcore/iter/range.rs
index 72b48b565719c90271a57d61cd7a806fe4d5c51c..5d57207763e47b671306ca3674f20da7cfd7eb14 100644 (file)
--- a/src/libcore/iter/range.rs
+++ b/src/libcore/iter/range.rs
@@ -488,6 +488,7 @@ fn private_try_from(value: usize) -> Result<Self, ()> {
 }
 
 // unsigned to signed (only positive bound)
+#[cfg(any(target_pointer_width = "32", target_pointer_width = "64"))]
 macro_rules! try_from_upper_bounded {
     ($($target:ty),*) => {$(
         impl PrivateTryFromUsize for $target {