diff --git a/build.rs b/build.rs
index 0f3df92..26c0c44 100644
--- a/build.rs
+++ b/build.rs
@@ -54,8 +54,6 @@ type ConditionalCfg = (Cfg, &'static [(Date, Cfg)]);
 const CONDITIONAL_CFGS: &'static [ConditionalCfg] = &[
 	(None, &[("2019-02-24", Some("pattern_guards"))]),
 	(None, &[("2018-08-14", Some("non_exhaustive"))]),
-	(Some("collections"), &[("2018-08-13", None)]),
-	(Some("str_char"), &[("2018-08-13", None)]),
 	(Some("unicode"), &[("2018-08-13", None)]),
 	(None, &[("2018-01-01", Some("core_memchr"))]),
 	(None, &[("2017-06-15", Some("no_collections"))]),
diff --git a/src/lib.rs b/src/lib.rs
index c527005..72c1bb5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -7,9 +7,9 @@
        doc_spotlight,slice_internals)]
 #![cfg_attr(any(feature="alloc",feature="collections"),feature(alloc))]
 #![cfg_attr(pattern_guards,feature(bind_by_move_pattern_guards,nll))]
-#![cfg_attr(collections,feature(collections))]
+#![cfg_attr(not(no_collections),feature(collections))]
 #![cfg_attr(non_exhaustive,feature(non_exhaustive))]
-#![cfg_attr(str_char,feature(str_char))]
+#![cfg_attr(unicode,feature(str_char))]
 #![cfg_attr(unicode,feature(unicode))]
 #![no_std]