diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6dca244c..3c4268d0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Add support for `graphql-ws` pings. [#635](https://github.com/async-graphql/async-graphql/issues/635)
 - Add feature gate `websocket` for async-graphql-tide. [#636](https://github.com/async-graphql/async-graphql/issues/636)
+- Implement GraphQL enum to `Value` conversion. [#617](https://github.com/async-graphql/async-graphql/issues/617)
+- Implement `ScalarType` for `HashMap`/`BTreeMap` to use `ToString`/`FromStr`. [#585](https://github.com/async-graphql/async-graphql/issues/585)
 
 ## [2.9.15] 2021-09-10
 
diff --git a/derive/src/enum.rs b/derive/src/enum.rs
index 40432691..781d8815 100644
--- a/derive/src/enum.rs
+++ b/derive/src/enum.rs
@@ -167,7 +167,7 @@ pub fn generate(enum_args: &args::Enum) -> GeneratorResult<TokenStream> {
             }
         }
 
-        impl From<#ident> for #crate_name::Value {
+        impl ::std::convert::From<#ident> for #crate_name::Value {
             fn from(value: #ident) -> #crate_name::Value {
                 #crate_name::resolver_utils::enum_value(value)
             }
diff --git a/src/types/external/json_object/btreemap.rs b/src/types/external/json_object/btreemap.rs
index 932d53f0..c3f14660 100644
--- a/src/types/external/json_object/btreemap.rs
+++ b/src/types/external/json_object/btreemap.rs
@@ -1,4 +1,6 @@
 use std::collections::BTreeMap;
+use std::fmt::Display;
+use std::str::FromStr;
 
 use crate::{
     InputType, InputValueError, InputValueResult, Name, OutputType, Scalar, ScalarType, Value,
@@ -6,15 +8,24 @@ use crate::{
 
 /// A scalar that can represent any JSON Object value.
 #[Scalar(internal, name = "JSONObject")]
-impl<T> ScalarType for BTreeMap<String, T>
+impl<K, T> ScalarType for BTreeMap<K, T>
 where
+    K: ToString + FromStr + Ord + Sync + Send,
+    K::Err: Display,
     T: OutputType + InputType,
 {
     fn parse(value: Value) -> InputValueResult<Self> {
         match value {
             Value::Object(map) => map
                 .into_iter()
-                .map(|(name, value)| Ok((name.to_string(), T::parse(Some(value))?)))
+                .map(|(name, value)| {
+                    Ok((
+                        K::from_str(&name).map_err(|err| {
+                            InputValueError::custom(format!("object key: {}", err))
+                        })?,
+                        T::parse(Some(value))?,
+                    ))
+                })
                 .collect::<Result<_, _>>()
                 .map_err(InputValueError::propagate),
             _ => Err(InputValueError::expected_type(value)),
@@ -24,7 +35,7 @@ where
     fn to_value(&self) -> Value {
         let mut map = BTreeMap::new();
         for (name, value) in self {
-            map.insert(Name::new(name), value.to_value());
+            map.insert(Name::new(name.to_string()), value.to_value());
         }
         Value::Object(map)
     }
diff --git a/src/types/external/json_object/hashmap.rs b/src/types/external/json_object/hashmap.rs
index 3e43d288..d805f6ca 100644
--- a/src/types/external/json_object/hashmap.rs
+++ b/src/types/external/json_object/hashmap.rs
@@ -1,4 +1,7 @@
 use std::collections::{BTreeMap, HashMap};
+use std::fmt::Display;
+use std::hash::Hash;
+use std::str::FromStr;
 
 use crate::{
     InputType, InputValueError, InputValueResult, Name, OutputType, Scalar, ScalarType, Value,
@@ -6,15 +9,24 @@ use crate::{
 
 /// A scalar that can represent any JSON Object value.
 #[Scalar(internal, name = "JSONObject")]
-impl<T> ScalarType for HashMap<String, T>
+impl<K, V> ScalarType for HashMap<K, V>
 where
-    T: OutputType + InputType,
+    K: ToString + FromStr + Eq + Hash + Sync + Send,
+    K::Err: Display,
+    V: OutputType + InputType,
 {
     fn parse(value: Value) -> InputValueResult<Self> {
         match value {
             Value::Object(map) => map
                 .into_iter()
-                .map(|(name, value)| Ok((name.to_string(), T::parse(Some(value))?)))
+                .map(|(name, value)| {
+                    Ok((
+                        K::from_str(&name).map_err(|err| {
+                            InputValueError::custom(format!("object key: {}", err))
+                        })?,
+                        V::parse(Some(value))?,
+                    ))
+                })
                 .collect::<Result<_, _>>()
                 .map_err(InputValueError::propagate),
             _ => Err(InputValueError::expected_type(value)),
@@ -24,7 +36,7 @@ where
     fn to_value(&self) -> Value {
         let mut map = BTreeMap::new();
         for (name, value) in self {
-            map.insert(Name::new(name), value.to_value());
+            map.insert(Name::new(name.to_string()), value.to_value());
         }
         Value::Object(map)
     }