Hyphenate cargo cfgs
diff --git a/Cargo.toml b/Cargo.toml
index 6558d4b..d8a81db 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -22,7 +22,7 @@
 parsing = []
 printing = ["quote"]
 visit = []
-visit_mut = []
+visit-mut = []
 fold = []
 clone-impls = []
 extra-traits = []
diff --git a/src/gen_helper.rs b/src/gen_helper.rs
index 97a6cec..b981f32 100644
--- a/src/gen_helper.rs
+++ b/src/gen_helper.rs
@@ -123,7 +123,7 @@
     }
 }
 
-#[cfg(feature = "visit_mut")]
+#[cfg(feature = "visit-mut")]
 pub mod visit_mut {
     use proc_macro2::Span;
     use visit_mut::VisitMut;
diff --git a/src/lib.rs b/src/lib.rs
index 937953c..952af8e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -391,7 +391,7 @@
     #[cfg(feature = "visit")]
     pub mod visit;
 
-    #[cfg(feature = "visit_mut")]
+    #[cfg(feature = "visit-mut")]
     pub mod visit_mut;
 
     #[cfg(feature = "fold")]