1 files changed, 7 insertions, 6 deletions

diff --git a/src/map.rs b/src/map.rs
index 1f693ac..2364941 100644
--- a/src/map.rs
+++ b/src/map.rs
@@ -1,3 +1,4 @@
+use std::error::Error;
 use textwrap::fill;
 
 pub use crate::from_yaml;
@@ -5,7 +6,7 @@ pub use crate::Status;
 pub use crate::Step;
 
 /// Error in Roadmap, from parsing or otherwise.
-pub type RoadmapError<T> = Result<T, String>;
+pub type RoadmapResult<T> = Result<T, Box<dyn Error>>;
 
 /// Represent a full project roadmap.
 ///
@@ -117,12 +118,12 @@ impl Roadmap {
     }
 
     // Validate that the parsed, constructed roadmap is valid.
-    pub fn validate(&self) -> RoadmapError<()> {
+    pub fn validate(&self) -> RoadmapResult<()> {
         // Is there exactly one goal?
         match self.count_goals() {
-            0 => return Err(format!("the roadmap doesn't have a goal")),
+            0 => return Err(format!("the roadmap doesn't have a goal").into()),
             1 => (),
-            _ => return Err(format!("must have exactly one goal for roadmap")),
+            _ => return Err(format!("must have exactly one goal for roadmap").into()),
         }
 
         // Does every dependency exist?
@@ -134,7 +135,7 @@ impl Roadmap {
                             "step {} depends on missing {}",
                             step.name(),
                             depname
-                        ))
+                        ).into())
                     }
                     Some(_) => (),
                 }
@@ -147,7 +148,7 @@ impl Roadmap {
     /// Get a Graphviz dot language representation of a roadmap. This
     /// is the textual representation, and the caller needs to use the
     /// Graphviz dot(1) tool to create an image from it.
-    pub fn format_as_dot(&self, label_width: usize) -> Result<String, Box<dyn std::error::Error>> {
+    pub fn format_as_dot(&self, label_width: usize) -> RoadmapResult<String> {
         self.validate()?;
 
         let labels = self.steps.iter().map(|step| {