diff --git a/aoc2015/src/day01.rs b/aoc2015/src/day01.rs
index d21a03f..a9ed0ea 100644
--- a/aoc2015/src/day01.rs
+++ b/aoc2015/src/day01.rs
@@ -1,5 +1,3 @@
-use std::error::Error;
-
 use super::err;
 use super::Result;
 
diff --git a/aoc2015/src/lib.rs b/aoc2015/src/lib.rs
index 656543d..dc48b07 100644
--- a/aoc2015/src/lib.rs
+++ b/aoc2015/src/lib.rs
@@ -4,5 +4,5 @@ pub type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;
 
 #[macro_export]
 macro_rules! err {
-    ($($string:expr),+) => (Box::<dyn Error>::from(format!($($string),+)))
+    ($($string:expr),+) => (Box::<dyn std::error::Error>::from(format!($($string),+)))
 }
diff --git a/aoc2018/src/lib.rs b/aoc2018/src/lib.rs
index 69d6b3b..e6a1200 100644
--- a/aoc2018/src/lib.rs
+++ b/aoc2018/src/lib.rs
@@ -8,5 +8,5 @@ pub type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;
 
 #[macro_export]
 macro_rules! err {
-    ($($string:expr),+) => (Box::<dyn Error>::from(format!($($string),+)))
+    ($($string:expr),+) => (Box::<dyn std::error::Error>::from(format!($($string),+)))
 }
diff --git a/aoc2019/src/lib.rs b/aoc2019/src/lib.rs
index 656543d..dc48b07 100644
--- a/aoc2019/src/lib.rs
+++ b/aoc2019/src/lib.rs
@@ -4,5 +4,5 @@ pub type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;
 
 #[macro_export]
 macro_rules! err {
-    ($($string:expr),+) => (Box::<dyn Error>::from(format!($($string),+)))
+    ($($string:expr),+) => (Box::<dyn std::error::Error>::from(format!($($string),+)))
 }