Manually implement fmt::Display and drop dependency on derive_more

Cargo.toml

@@ -16,7 +16,6 @@ serde_json = "1.0"
 reqwest = { version = "0.12", default-features = false }
 chrono = { version = "0.4", features = ["serde"] }
 chrono-tz = "0.8"
-derive_more = "0.99"
 
 [features]
 default = ["reqwest/native-tls"]

src/error.rs

@@ -1,22 +1,27 @@
-use derive_more::Display;
-
 /// Set of errors which can occur when calling the API.
-#[derive(Display, Debug)]
+#[derive(Debug)]
 pub enum Error {
     /// Error establishing a network connection.
-    #[display(fmt = "connection error: {}", _0)]
     ConnectionError(String),
     /// HTTP error returned by the API.
-    #[display(fmt = "server returned HTTP status code {}", _0)]
     ServerError(u16),
     /// Error parsing the API response.
-    #[display(fmt = "parsing error: {}", _0)]
     ParsingError(String),
     /// Error returned by the API.
-    #[display(fmt = "API error: {}", _0)]
     APIError(String),
 }
 
+impl std::fmt::Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Error::ConnectionError(e) => write!(f, "connection error: {}", e),
+            Error::ServerError(e) => write!(f, "server returned HTTP status code {}", e),
+            Error::ParsingError(e) => write!(f, "parsing error: {}", e),
+            Error::APIError(e) => write!(f, "API error: {}", e),
+        }
+    }
+}
+
 impl std::error::Error for Error {}
 
 impl From<reqwest::Error> for Error {