From 644fdf8c6be7b716632af43fc2f4cba882f75e91 Mon Sep 17 00:00:00 2001
From: Jacob Rothstein <hi@jbr.me>
Date: Wed, 5 Aug 2020 10:12:01 -0700
Subject: [PATCH 1/2] Track type name on error before losing that info

---
 src/error.rs | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/error.rs b/src/error.rs
index a6eae7ea..0f76ce56 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -16,6 +16,7 @@ pub type Result<T> = std::result::Result<T, Error>;
 pub struct Error {
     error: anyhow::Error,
     status: crate::StatusCode,
+    type_name: Option<String>,
 }
 
 impl Error {
@@ -24,16 +25,18 @@ impl Error {
     /// The error type must be threadsafe and 'static, so that the Error will be
     /// as well. If the error type does not provide a backtrace, a backtrace will
     /// be created here to ensure that a backtrace exists.
-    pub fn new<S>(status: S, error: impl Into<anyhow::Error>) -> Self
+    pub fn new<S, E>(status: S, error: E) -> Self
     where
         S: TryInto<StatusCode>,
         S::Error: Debug,
+        E: Into<anyhow::Error>,
     {
         Self {
             status: status
                 .try_into()
                 .expect("Could not convert into a valid `StatusCode`"),
             error: error.into(),
+            type_name: Some(std::any::type_name::<E>().to_string()),
         }
     }
 
@@ -49,6 +52,7 @@ impl Error {
                 .try_into()
                 .expect("Could not convert into a valid `StatusCode`"),
             error: anyhow::Error::msg(msg),
+            type_name: None,
         }
     }
     /// Create a new error from a message.
@@ -112,6 +116,11 @@ impl Error {
     {
         self.error.downcast_mut::<E>()
     }
+
+    /// Retrieves a reference to the type name of the error, if available.
+    pub fn type_name(&self) -> Option<&str> {
+        self.type_name.as_deref()
+    }
 }
 
 impl Display for Error {

From 2c6e3f14a74a14ee8f9f30d7ad14bbeea838724e Mon Sep 17 00:00:00 2001
From: Jacob Rothstein <hi@jbr.me>
Date: Fri, 7 Aug 2020 13:06:00 -0700
Subject: [PATCH 2/2] Apply suggestions from code review

keep the type_name a &'static str

Co-authored-by: Yoshua Wuyts <yoshuawuyts+github@gmail.com>
---
 src/error.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/error.rs b/src/error.rs
index 0f76ce56..179adaa9 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -16,7 +16,7 @@ pub type Result<T> = std::result::Result<T, Error>;
 pub struct Error {
     error: anyhow::Error,
     status: crate::StatusCode,
-    type_name: Option<String>,
+    type_name: Option<&'static str>,
 }
 
 impl Error {
@@ -36,7 +36,7 @@ impl Error {
                 .try_into()
                 .expect("Could not convert into a valid `StatusCode`"),
             error: error.into(),
-            type_name: Some(std::any::type_name::<E>().to_string()),
+            type_name: Some(std::any::type_name::<E>()),
         }
     }