diff --git a/test_suite/tests/test_de.rs b/test_suite/tests/test_de.rs
index b4ca2e19..0218cab8 100644
--- a/test_suite/tests/test_de.rs
+++ b/test_suite/tests/test_de.rs
@@ -14,7 +14,7 @@ extern crate serde_derive;
 
 use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
 use std::default::Default;
-use std::ffi::{CString, OsString};
+use std::ffi::{CStr, CString, OsString};
 use std::net;
 use std::num::Wrapping;
 use std::path::{Path, PathBuf};
@@ -22,9 +22,6 @@ use std::rc::{Rc, Weak as RcWeak};
 use std::sync::{Arc, Weak as ArcWeak};
 use std::time::{Duration, UNIX_EPOCH};
 
-#[cfg(feature = "unstable")]
-use std::ffi::CStr;
-
 extern crate serde;
 use serde::{Deserialize, Deserializer};
 
@@ -866,6 +863,26 @@ declare_tests! {
             Token::U64(1),
         ],
     }
+    test_rc_dst {
+        Rc::<str>::from("s") => &[
+            Token::Str("s"),
+        ],
+        Rc::<[bool]>::from(&[true][..]) => &[
+            Token::Seq { len: Some(1) },
+            Token::Bool(true),
+            Token::SeqEnd,
+        ],
+    }
+    test_arc_dst {
+        Arc::<str>::from("s") => &[
+            Token::Str("s"),
+        ],
+        Arc::<[bool]>::from(&[true][..]) => &[
+            Token::Seq { len: Some(1) },
+            Token::Bool(true),
+            Token::SeqEnd,
+        ],
+    }
 }
 
 declare_tests! {
@@ -961,30 +978,6 @@ declare_tests! {
     }
 }
 
-#[cfg(feature = "unstable")]
-declare_tests! {
-    test_rc_dst {
-        Rc::<str>::from("s") => &[
-            Token::Str("s"),
-        ],
-        Rc::<[bool]>::from(&[true][..]) => &[
-            Token::Seq { len: Some(1) },
-            Token::Bool(true),
-            Token::SeqEnd,
-        ],
-    }
-    test_arc_dst {
-        Arc::<str>::from("s") => &[
-            Token::Str("s"),
-        ],
-        Arc::<[bool]>::from(&[true][..]) => &[
-            Token::Seq { len: Some(1) },
-            Token::Bool(true),
-            Token::SeqEnd,
-        ],
-    }
-}
-
 #[cfg(feature = "unstable")]
 declare_tests! {
     test_never_result {
@@ -1035,7 +1028,6 @@ fn test_osstring() {
     assert_de_tokens_ignore(&tokens);
 }
 
-#[cfg(feature = "unstable")]
 #[test]
 fn test_cstr() {
     assert_de_tokens::<Box<CStr>>(
@@ -1044,7 +1036,6 @@ fn test_cstr() {
     );
 }
 
-#[cfg(feature = "unstable")]
 #[test]
 fn test_cstr_internal_null() {
     assert_de_tokens_error::<Box<CStr>>(
@@ -1053,7 +1044,6 @@ fn test_cstr_internal_null() {
     );
 }
 
-#[cfg(feature = "unstable")]
 #[test]
 fn test_cstr_internal_null_end() {
     assert_de_tokens_error::<Box<CStr>>(
diff --git a/test_suite/tests/test_gen.rs b/test_suite/tests/test_gen.rs
index ef301b59..82e4dfc0 100644
--- a/test_suite/tests/test_gen.rs
+++ b/test_suite/tests/test_gen.rs
@@ -297,11 +297,9 @@ fn test_gen() {
         f: u8,
     }
 
-    #[cfg(feature = "unstable")]
     #[derive(Serialize, Deserialize)]
     struct EmptyTuple();
 
-    #[cfg(feature = "unstable")]
     #[derive(Serialize, Deserialize)]
     #[serde(deny_unknown_fields)]
     struct EmptyTupleDenyUnknown();
@@ -327,7 +325,6 @@ fn test_gen() {
         Variant,
     }
 
-    #[cfg(feature = "unstable")]
     #[derive(Serialize, Deserialize)]
     enum EmptyVariants {
         Braced {},
@@ -339,7 +336,6 @@ fn test_gen() {
         TupleSkip(#[serde(skip_deserializing)] u8),
     }
 
-    #[cfg(feature = "unstable")]
     #[derive(Serialize, Deserialize)]
     #[serde(deny_unknown_fields)]
     enum EmptyVariantsDenyUnknown {
diff --git a/test_suite/tests/test_ser.rs b/test_suite/tests/test_ser.rs
index 0d4a35de..cd4ce6bf 100644
--- a/test_suite/tests/test_ser.rs
+++ b/test_suite/tests/test_ser.rs
@@ -442,6 +442,26 @@ declare_tests! {
             Token::U64(1),
         ],
     }
+    test_rc_dst {
+        Rc::<str>::from("s") => &[
+            Token::Str("s"),
+        ],
+        Rc::<[bool]>::from(&[true][..]) => &[
+            Token::Seq { len: Some(1) },
+            Token::Bool(true),
+            Token::SeqEnd,
+        ],
+    }
+    test_arc_dst {
+        Arc::<str>::from("s") => &[
+            Token::Str("s"),
+        ],
+        Arc::<[bool]>::from(&[true][..]) => &[
+            Token::Seq { len: Some(1) },
+            Token::Bool(true),
+            Token::SeqEnd,
+        ],
+    }
 }
 
 declare_tests! {
@@ -525,31 +545,6 @@ declare_tests! {
     }
 }
 
-// Serde's implementation is not unstable, but the constructors are.
-#[cfg(feature = "unstable")]
-declare_tests! {
-    test_rc_dst {
-        Rc::<str>::from("s") => &[
-            Token::Str("s"),
-        ],
-        Rc::<[bool]>::from(&[true][..]) => &[
-            Token::Seq { len: Some(1) },
-            Token::Bool(true),
-            Token::SeqEnd,
-        ],
-    }
-    test_arc_dst {
-        Arc::<str>::from("s") => &[
-            Token::Str("s"),
-        ],
-        Arc::<[bool]>::from(&[true][..]) => &[
-            Token::Seq { len: Some(1) },
-            Token::Bool(true),
-            Token::SeqEnd,
-        ],
-    }
-}
-
 #[cfg(feature = "unstable")]
 declare_tests! {
     test_never_result {