Refactor error to use dynamic dispatch and traits

This is in preperation for dynamic import (#1789), which is more easily
implemented when errors are dynamic.

1 files changed, 7 insertions, 0 deletions

diff --git a/cli/diagnostics.rs b/cli/diagnostics.rs
index 69b58459e..14f5ba2c4 100644
--- a/cli/diagnostics.rs
+++ b/cli/diagnostics.rs
@@ -7,6 +7,7 @@ use crate::fmt_errors::format_maybe_source_name;
 use crate::fmt_errors::DisplayFormatter;
 use serde_json;
 use serde_json::value::Value;
+use std::error::Error;
 use std::fmt;
 
 #[derive(Debug, PartialEq, Clone)]
@@ -66,6 +67,12 @@ impl fmt::Display for Diagnostic {
   }
 }
 
+impl Error for Diagnostic {
+  fn description(&self) -> &str {
+    &self.items[0].message
+  }
+}
+
 #[derive(Debug, PartialEq, Clone)]
 pub struct DiagnosticItem {
   /// The top level message relating to the diagnostic item.