diff --git a/src/formatter/mod.rs b/src/formatter/mod.rs
index 45fee74..189c90d 100644
--- a/src/formatter/mod.rs
+++ b/src/formatter/mod.rs
@@ -47,7 +47,7 @@ fn repeat_char(c: char, n: usize) -> String {
 /// assert_eq!(dlf.format(&dl), "192 | Example line of text");
 /// ```
 pub struct DisplayListFormatter {
-    stylesheet: Box<Stylesheet>,
+    stylesheet: Box<dyn Stylesheet>,
 }
 
 impl DisplayListFormatter {
@@ -101,7 +101,7 @@ impl DisplayListFormatter {
         }
     }
 
-    fn get_annotation_style(&self, annotation_type: &DisplayAnnotationType) -> Box<Style> {
+    fn get_annotation_style(&self, annotation_type: &DisplayAnnotationType) -> Box<dyn Style> {
         self.stylesheet.get_style(match annotation_type {
             DisplayAnnotationType::Error => StyleClass::Error,
             DisplayAnnotationType::Warning => StyleClass::Warning,
diff --git a/src/formatter/style.rs b/src/formatter/style.rs
index 5720784..c1b9046 100644
--- a/src/formatter/style.rs
+++ b/src/formatter/style.rs
@@ -87,12 +87,12 @@ pub trait Style {
     fn paint(&self, text: &str) -> String;
     /// The method used by the DisplayListFormatter to display the message
     /// in bold font.
-    fn bold(&self) -> Box<Style>;
+    fn bold(&self) -> Box<dyn Style>;
 }
 
 /// Trait to annotate structs that can provide `Style` implementations for
 /// every `StyleClass` variant.
 pub trait Stylesheet {
     /// Returns a `Style` implementer based on the requested `StyleClass` variant.
-    fn get_style(&self, class: StyleClass) -> Box<Style>;
+    fn get_style(&self, class: StyleClass) -> Box<dyn Style>;
 }
diff --git a/src/lib.rs b/src/lib.rs
index b34157f..46b25e1 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,5 @@
+#![deny(rust_2018_idioms)]
+
 //! A library for formatting of text or programming code snippets.
 //!
 //! It's primary purpose is to build an ASCII-graphical representation of the snippet
diff --git a/src/stylesheets/no_color.rs b/src/stylesheets/no_color.rs
index cd6008c..608e4e5 100644
--- a/src/stylesheets/no_color.rs
+++ b/src/stylesheets/no_color.rs
@@ -7,7 +7,7 @@ impl Style for NoOpStyle {
         text.to_string()
     }
 
-    fn bold(&self) -> Box<Style> {
+    fn bold(&self) -> Box<dyn Style> {
         Box::new(NoOpStyle {})
     }
 }
@@ -15,7 +15,7 @@ impl Style for NoOpStyle {
 pub struct NoColorStylesheet {}
 
 impl Stylesheet for NoColorStylesheet {
-    fn get_style(&self, _class: StyleClass) -> Box<Style> {
+    fn get_style(&self, _class: StyleClass) -> Box<dyn Style> {
         Box::new(NoOpStyle {})
     }
 }