Recommend to implement From.

Author: calavera

README.md

@@ -86,19 +86,19 @@ The Rust Runtime for Lambda uses a struct called `Diagnostic` to represent funct
 
 ### Implement your own Diagnostic
 
-To get more descriptive `error_type` fields, you can implement `Into<Diagnostic>` for your error type. That gives you full control on what the `error_type` is:
+To get more descriptive `error_type` fields, you can implement `From` for your error type. That gives you full control on what the `error_type` is:
 
 ```rust
 use lambda_runtime::{Diagnostic, Error, LambdaEvent};
 
 #[derive(Debug)]
 struct ErrorResponse(&'static str);
 
-impl Into<Diagnostic> for ErrorResponse {
-    fn into(self) -> Diagnostic {
+impl From<ErrorResponse> for Diagnostic {
+    fn into(error: ErrorResponse) -> Diagnostic {
         Diagnostic {
             error_type: "MyErrorType".into(),
-            error_message: self.0.to_string(),
+            error_message: error.0.to_string(),
         }
     }
 }

lambda-runtime/src/diagnostic.rs

@@ -14,8 +14,9 @@ use crate::{deserializer::DeserializeError, Error};
 /// [`error_type`][`Diagnostic::error_type`] is derived from the type name of
 /// the original error with [`std::any::type_name`] as a fallback, which may
 /// not be reliable for conditional error handling.
-/// You can define your own error container that implements `Into<Diagnostic>`
-/// if you need to handle errors based on error types.
+///
+/// To get more descriptive [`error_type`][`Diagnostic::error_type`] fields, you can implement `From` for your error type.
+/// That gives you full control on what the `error_type` is.
 ///
 /// Example:
 /// ```
@@ -24,11 +25,11 @@ use crate::{deserializer::DeserializeError, Error};
 /// #[derive(Debug)]
 /// struct ErrorResponse(&'static str);
 ///
-/// impl Into<Diagnostic> for ErrorResponse {
-///     fn into(self) -> Diagnostic {
+/// impl From<ErrorResponse> for Diagnostic {
+///     fn into(error: ErrorResponse) -> Diagnostic {
 ///         Diagnostic {
 ///             error_type: "MyError".into(),
-///             error_message: self.0.to_string(),
+///             error_message: error.0.to_string(),
 ///         }
 ///     }
 /// }