diff --git a/src/lib.rs b/src/lib.rs
index 26b9c77..4bc2c40 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -763,7 +763,7 @@ pub fn float(input: TokenStream) -> TokenStream {
                 <#inner_ty as #import::Float>::is_normal(self.0)
             }
             #[inline]
-            fn classify(self) -> ::std::num::FpCategory {
+            fn classify(self) -> ::core::num::FpCategory {
                 <#inner_ty as #import::Float>::classify(self.0)
             }
             #[inline]