chore: Remove ScalarRefValue trait

The trait was introduced while introducing generic scalars, but is not
actually required or useful. It's functionality is fully covered by
methods on the `ScalarValue` trait.

It also forced a lof of for<'a> ScalarRefValue bounds all over the code,
complicating signatures a lot.

It is completely removed now.

juniper/src/ast.rs

@@ -5,7 +5,7 @@ use indexmap::IndexMap;
 use crate::{
     executor::Variables,
     parser::Spanning,
-    value::{DefaultScalarValue, ScalarRefValue, ScalarValue},
+    value::{DefaultScalarValue, ScalarValue},
 };
 
 /// A type literal in the syntax tree
@@ -152,9 +152,7 @@ pub type Document<'a, S> = Vec<Definition<'a, S>>;
 /// Must be implemented manually when manually exposing new enums or scalars.
 pub trait FromInputValue<S = DefaultScalarValue>: Sized {
     /// Performs the conversion.
-    fn from_input_value(v: &InputValue<S>) -> Option<Self>
+    fn from_input_value(v: &InputValue<S>) -> Option<Self>;
-    where
-        for<'b> &'b S: ScalarRefValue<'b>;
 }
 
 /// Losslessly clones a Rust data type into an InputValue.
@@ -316,7 +314,6 @@ where
     pub fn convert<T>(&self) -> Option<T>
     where
         T: FromInputValue<S>,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         <T as FromInputValue<S>>::from_input_value(self)
     }
@@ -346,30 +343,18 @@ where
     }
 
     /// View the underlying int value, if present.
-    #[deprecated(since = "0.11.0", note = "Use `InputValue::as_scalar_value` instead")]
+    pub fn as_int_value<'a>(&'a self) -> Option<i32> {
-    pub fn as_int_value<'a>(&'a self) -> Option<i32>
+        self.as_scalar_value().and_then(|s| s.as_int())
-    where
-        &'a S: Into<Option<&'a i32>>,
-    {
-        self.as_scalar_value().cloned()
     }
 
     /// View the underlying float value, if present.
-    #[deprecated(since = "0.11.0", note = "Use `InputValue::as_scalar_value` instead")]
+    pub fn as_float_value<'a>(&'a self) -> Option<f64> {
-    pub fn as_float_value<'a>(&'a self) -> Option<f64>
+        self.as_scalar_value().and_then(|s| s.as_float())
-    where
-        &'a S: Into<Option<&'a f64>>,
-    {
-        self.as_scalar_value().cloned()
     }
 
     /// View the underlying string value, if present.
-    #[deprecated(since = "0.11.0", note = "Use `InputValue::as_scalar_value` instead")]
+    pub fn as_string_value<'a>(&'a self) -> Option<&'a str> {
-    pub fn as_string_value<'a>(&'a self) -> Option<&'a str>
+        self.as_scalar_value().and_then(|s| s.as_str())
-    where
-        &'a S: Into<Option<&'a String>>,
-    {
-        self.as_scalar_value().map(|s| s as &str)
     }
 
     /// View the underlying scalar value, if present.
@@ -459,13 +444,17 @@ where
 impl<S> fmt::Display for InputValue<S>
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
             InputValue::Null => write!(f, "null"),
-            InputValue::Scalar(ref s) if s.is_type::<String>() => write!(f, "\"{}\"", s),
+            InputValue::Scalar(ref s) => {
-            InputValue::Scalar(ref s) => write!(f, "{}", s),
+                if let Some(s) = s.as_str() {
+                    write!(f, "\"{}\"", s)
+                } else {
+                    write!(f, "{}", s)
+                }
+            }
             InputValue::Enum(ref v) => write!(f, "{}", v),
             InputValue::Variable(ref v) => write!(f, "${}", v),
             InputValue::List(ref v) => {

juniper/src/executor/look_ahead.rs

@@ -1,7 +1,7 @@
 use crate::{
     ast::{Directive, Fragment, InputValue, Selection},
     parser::Spanning,
-    value::{ScalarRefValue, ScalarValue},
+    value::ScalarValue,
 };
 
 use std::collections::HashMap;
@@ -117,7 +117,6 @@ pub struct LookAheadSelection<'a, S: 'a> {
 impl<'a, S> Default for LookAheadSelection<'a, S>
 where
     S: ScalarValue,
-    &'a S: ScalarRefValue<'a>,
 {
     fn default() -> Self {
         LookAheadSelection {
@@ -132,7 +131,6 @@ where
 impl<'a, S> LookAheadSelection<'a, S>
 where
     S: ScalarValue,
-    &'a S: ScalarRefValue<'a>,
 {
     fn should_include<'b, 'c>(
         directives: Option<&'b Vec<Spanning<Directive<S>>>>,
@@ -157,9 +155,7 @@ where
                                 if let LookAheadValue::Scalar(s) =
                                     LookAheadValue::from_input_value(&v.item, vars)
                                 {
-                                    <&S as Into<Option<&bool>>>::into(s)
+                                    s.as_boolean().unwrap_or(false)
-                                        .cloned()
-                                        .unwrap_or(false)
                                 } else {
                                     false
                                 }
@@ -174,9 +170,7 @@ where
                                 if let LookAheadValue::Scalar(b) =
                                     LookAheadValue::from_input_value(&v.item, vars)
                                 {
-                                    <&S as Into<Option<&bool>>>::into(b)
+                                    b.as_boolean().map(::std::ops::Not::not).unwrap_or(false)
-                                        .map(::std::ops::Not::not)
-                                        .unwrap_or(false)
                                 } else {
                                     false
                                 }
@@ -439,14 +433,13 @@ mod tests {
         parser::UnlocatedParseResult,
         schema::model::SchemaType,
         validation::test_harness::{MutationRoot, QueryRoot},
-        value::{DefaultScalarValue, ScalarRefValue, ScalarValue},
+        value::{DefaultScalarValue, ScalarValue},
     };
     use std::collections::HashMap;
 
     fn parse_document_source<S>(q: &str) -> UnlocatedParseResult<Document<S>>
     where
         S: ScalarValue,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         crate::parse_document_source(q, &SchemaType::new::<QueryRoot, MutationRoot>(&(), &()))
     }

juniper/src/executor/mod.rs

@@ -22,7 +22,7 @@ use crate::schema::{
 
 use crate::{
     types::{base::GraphQLType, name::Name},
-    value::{DefaultScalarValue, ParseScalarValue, ScalarRefValue, ScalarValue},
+    value::{DefaultScalarValue, ParseScalarValue, ScalarValue},
 };
 
 mod look_ahead;
@@ -235,7 +235,6 @@ impl<S> IntoFieldError<S> for FieldError<S> {
 pub trait IntoResolvable<'a, S, T: GraphQLType<S>, C>: Sized
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     #[doc(hidden)]
     fn into(self, ctx: &'a C) -> FieldResult<Option<(&'a T::Context, T)>, S>;
@@ -246,7 +245,6 @@ where
     T: GraphQLType<S>,
     S: ScalarValue,
     T::Context: FromContext<C>,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     fn into(self, ctx: &'a C) -> FieldResult<Option<(&'a T::Context, T)>, S> {
         Ok(Some((FromContext::from(ctx), self)))
@@ -258,7 +256,6 @@ where
     S: ScalarValue,
     T: GraphQLType<S>,
     T::Context: FromContext<C>,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     fn into(self, ctx: &'a C) -> FieldResult<Option<(&'a T::Context, T)>, S> {
         self.map(|v: T| Some((<T::Context as FromContext<C>>::from(ctx), v)))
@@ -270,7 +267,6 @@ impl<'a, S, T, C> IntoResolvable<'a, S, T, C> for (&'a T::Context, T)
 where
     S: ScalarValue,
     T: GraphQLType<S>,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     fn into(self, _: &'a C) -> FieldResult<Option<(&'a T::Context, T)>, S> {
         Ok(Some(self))
@@ -281,7 +277,6 @@ impl<'a, S, T, C> IntoResolvable<'a, S, Option<T>, C> for Option<(&'a T::Context
 where
     S: ScalarValue,
     T: GraphQLType<S>,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     fn into(self, _: &'a C) -> FieldResult<Option<(&'a T::Context, Option<T>)>, S> {
         Ok(self.map(|(ctx, v)| (ctx, Some(v))))
@@ -292,7 +287,6 @@ impl<'a, S, T, C> IntoResolvable<'a, S, T, C> for FieldResult<(&'a T::Context, T
 where
     S: ScalarValue,
     T: GraphQLType<S>,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     fn into(self, _: &'a C) -> FieldResult<Option<(&'a T::Context, T)>, S> {
         self.map(Some)
@@ -304,7 +298,6 @@ impl<'a, S, T, C> IntoResolvable<'a, S, Option<T>, C>
 where
     S: ScalarValue,
     T: GraphQLType<S>,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     fn into(self, _: &'a C) -> FieldResult<Option<(&'a T::Context, Option<T>)>, S> {
         self.map(|o| o.map(|(ctx, v)| (ctx, Some(v))))
@@ -352,7 +345,6 @@ where
 impl<'a, CtxT, S> Executor<'a, CtxT, S>
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     /// Resolve a single arbitrary value, mapping the context to a new type
     pub fn resolve_with_ctx<NewCtxT, T>(&self, info: &T::TypeInfo, value: &T) -> ExecutionResult<S>
@@ -671,7 +663,6 @@ where
     S: ScalarValue,
     QueryT: GraphQLType<S, Context = CtxT>,
     MutationT: GraphQLType<S, Context = CtxT>,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     let mut fragments = vec![];
     let mut operation = None;
@@ -786,7 +777,6 @@ where
     MutationT: crate::GraphQLTypeAsync<S, Context = CtxT> + Send + Sync,
     MutationT::TypeInfo: Send + Sync,
     CtxT: Send + Sync,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     let mut fragments = vec![];
     let mut operation = None;
@@ -908,7 +898,6 @@ where
     pub fn get_type<T>(&mut self, info: &T::TypeInfo) -> Type<'r>
     where
         T: GraphQLType<S>,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         if let Some(name) = T::name(info) {
             let validated_name = name.parse::<Name>().unwrap();
@@ -930,7 +919,6 @@ where
     pub fn field<T>(&mut self, name: &str, info: &T::TypeInfo) -> Field<'r, S>
     where
         T: GraphQLType<S>,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         Field {
             name: name.to_owned(),
@@ -949,7 +937,6 @@ where
     ) -> Field<'r, S>
     where
         I: GraphQLType<S>,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         Field {
             name: name.to_owned(),
@@ -964,7 +951,6 @@ where
     pub fn arg<T>(&mut self, name: &str, info: &T::TypeInfo) -> Argument<'r, S>
     where
         T: GraphQLType<S> + FromInputValue<S>,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         Argument::new(name, self.get_type::<T>(info))
     }
@@ -981,7 +967,6 @@ where
     ) -> Argument<'r, S>
     where
         T: GraphQLType<S> + ToInputValue<S> + FromInputValue<S>,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         Argument::new(name, self.get_type::<Option<T>>(info)).default_value(value.to_input_value())
     }
@@ -999,26 +984,22 @@ where
     pub fn build_scalar_type<T>(&mut self, info: &T::TypeInfo) -> ScalarMeta<'r, S>
     where
         T: FromInputValue<S> + GraphQLType<S> + ParseScalarValue<S> + 'r,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         let name = T::name(info).expect("Scalar types must be named. Implement name()");
         ScalarMeta::new::<T>(Cow::Owned(name.to_string()))
     }
 
     /// Create a list meta type
-    pub fn build_list_type<T: GraphQLType<S>>(&mut self, info: &T::TypeInfo) -> ListMeta<'r>
+    pub fn build_list_type<T: GraphQLType<S>>(&mut self, info: &T::TypeInfo) -> ListMeta<'r> {
-    where
-        for<'b> &'b S: ScalarRefValue<'b>,
-    {
         let of_type = self.get_type::<T>(info);
         ListMeta::new(of_type)
     }
 
     /// Create a nullable meta type
-    pub fn build_nullable_type<T: GraphQLType<S>>(&mut self, info: &T::TypeInfo) -> NullableMeta<'r>
+    pub fn build_nullable_type<T: GraphQLType<S>>(
-    where
+        &mut self,
-        for<'b> &'b S: ScalarRefValue<'b>,
+        info: &T::TypeInfo,
-    {
+    ) -> NullableMeta<'r> {
         let of_type = self.get_type::<T>(info);
         NullableMeta::new(of_type)
     }
@@ -1034,7 +1015,6 @@ where
     ) -> ObjectMeta<'r, S>
     where
         T: GraphQLType<S>,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         let name = T::name(info).expect("Object types must be named. Implement name()");
 
@@ -1051,7 +1031,6 @@ where
     ) -> EnumMeta<'r, S>
     where
         T: FromInputValue<S> + GraphQLType<S>,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         let name = T::name(info).expect("Enum types must be named. Implement name()");
 
@@ -1067,7 +1046,6 @@ where
     ) -> InterfaceMeta<'r, S>
     where
         T: GraphQLType<S>,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         let name = T::name(info).expect("Interface types must be named. Implement name()");
 
@@ -1080,7 +1058,6 @@ where
     pub fn build_union_type<T>(&mut self, info: &T::TypeInfo, types: &[Type<'r>]) -> UnionMeta<'r>
     where
         T: GraphQLType<S>,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         let name = T::name(info).expect("Union types must be named. Implement name()");
 
@@ -1095,7 +1072,6 @@ where
     ) -> InputObjectMeta<'r, S>
     where
         T: FromInputValue<S> + GraphQLType<S>,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         let name = T::name(info).expect("Input object types must be named. Implement name()");
 

juniper/src/http/mod.rs

@@ -12,7 +12,7 @@ use serde_derive::{Deserialize, Serialize};
 use crate::{
     ast::InputValue,
     executor::ExecutionError,
-    value::{DefaultScalarValue, ScalarRefValue, ScalarValue},
+    value::{DefaultScalarValue, ScalarValue},
     FieldError, GraphQLError, GraphQLType, RootNode, Value, Variables,
 };
 
@@ -83,7 +83,6 @@ where
         S: ScalarValue,
         QueryT: GraphQLType<S, Context = CtxT>,
         MutationT: GraphQLType<S, Context = CtxT>,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         GraphQLResponse(crate::execute(
             &self.query,
@@ -107,7 +106,6 @@ where
         MutationT: crate::GraphQLTypeAsync<S, Context = CtxT> + Send + Sync,
         MutationT::TypeInfo: Send + Sync,
         CtxT: Send + Sync,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         let op = self.operation_name();
         let vars = &self.variables();

juniper/src/integrations/chrono.rs

@@ -32,7 +32,7 @@ graphql_scalar!(DateTime<FixedOffset> as "DateTimeFixedOffset" where Scalar = <S
     }
 
     from_input_value(v: &InputValue) -> Option<DateTime<FixedOffset>> {
-        v.as_scalar_value::<String>()
+        v.as_string_value()
          .and_then(|s| DateTime::parse_from_rfc3339(s).ok())
     }
 
@@ -53,7 +53,7 @@ graphql_scalar!(DateTime<Utc> as "DateTimeUtc" where Scalar = <S>{
     }
 
     from_input_value(v: &InputValue) -> Option<DateTime<Utc>> {
-        v.as_scalar_value::<String>()
+        v.as_string_value()
          .and_then(|s| (s.parse::<DateTime<Utc>>().ok()))
     }
 
@@ -79,7 +79,7 @@ graphql_scalar!(NaiveDate where Scalar = <S>{
     }
 
     from_input_value(v: &InputValue) -> Option<NaiveDate> {
-        v.as_scalar_value::<String>()
+        v.as_string_value()
          .and_then(|s| NaiveDate::parse_from_str(s, "%Y-%m-%d").ok())
     }
 
@@ -102,8 +102,8 @@ graphql_scalar!(NaiveDateTime where Scalar = <S> {
     }
 
     from_input_value(v: &InputValue) -> Option<NaiveDateTime> {
-        v.as_scalar_value::<f64>()
+        v.as_float_value()
-         .and_then(|f| NaiveDateTime::from_timestamp_opt(*f as i64, 0))
+         .and_then(|f| NaiveDateTime::from_timestamp_opt(f as i64, 0))
     }
 
     from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {

juniper/src/integrations/url.rs

@@ -13,7 +13,7 @@ graphql_scalar!(Url where Scalar = <S>{
     }
 
     from_input_value(v: &InputValue) -> Option<Url> {
-        v.as_scalar_value::<String>()
+        v.as_string_value()
          .and_then(|s| Url::parse(s).ok())
     }
 

juniper/src/integrations/uuid.rs

@@ -14,7 +14,7 @@ graphql_scalar!(Uuid where Scalar = <S> {
     }
 
     from_input_value(v: &InputValue) -> Option<Uuid> {
-        v.as_scalar_value::<String>()
+        v.as_string_value()
          .and_then(|s| Uuid::parse_str(s).ok())
     }
 

juniper/src/lib.rs

@@ -170,10 +170,7 @@ pub use crate::{
         scalars::{EmptyMutation, ID},
     },
     validation::RuleError,
-    value::{
+    value::{DefaultScalarValue, Object, ParseScalarResult, ParseScalarValue, ScalarValue, Value},
-        DefaultScalarValue, Object, ParseScalarResult, ParseScalarValue, ScalarRefValue,
-        ScalarValue, Value,
-    },
 };
 
 /// A pinned, boxed future that can be polled.
@@ -204,7 +201,6 @@ pub fn execute<'a, S, CtxT, QueryT, MutationT>(
 ) -> Result<(Value<S>, Vec<ExecutionError<S>>), GraphQLError<'a>>
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
     QueryT: GraphQLType<S, Context = CtxT>,
     MutationT: GraphQLType<S, Context = CtxT>,
 {
@@ -246,7 +242,6 @@ where
     MutationT: GraphQLTypeAsync<S, Context = CtxT> + Send + Sync,
     MutationT::TypeInfo: Send + Sync,
     CtxT: Send + Sync,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     let document = parse_document_source(document_source, &root_node.schema)?;
     {
@@ -279,7 +274,6 @@ pub fn introspect<'a, S, CtxT, QueryT, MutationT>(
 ) -> Result<(Value<S>, Vec<ExecutionError<S>>), GraphQLError<'a>>
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
     QueryT: GraphQLType<S, Context = CtxT>,
     MutationT: GraphQLType<S, Context = CtxT>,
 {

juniper/src/macros/common.rs

@@ -32,7 +32,6 @@ macro_rules! __juniper_impl_trait {
        impl<$($other,)* $generic $(: $bound)*> $crate::$impl_trait<$generic> for $name
         where
             $generic: $crate::ScalarValue,
-            for<'__b> &'__b $generic: $crate::ScalarRefValue<'__b>,
        {
            $($body)*
        }
@@ -48,7 +47,6 @@ macro_rules! __juniper_impl_trait {
         where
             $($where)*
             $generic: $crate::ScalarValue,
-            for<'__b> &'__b $generic: $crate::ScalarRefValue<'__b>,
        {
            $($body)*
        }

juniper/src/macros/interface.rs

@@ -145,7 +145,7 @@ macro_rules! graphql_interface {
                     info: &Self::TypeInfo,
                     registry: &mut $crate::Registry<'r, $crate::__juniper_insert_generic!($($scalar)+)>
                 ) -> $crate::meta::MetaType<'r, $crate::__juniper_insert_generic!($($scalar)+)>
-                where for<'__b> &'__b $crate::__juniper_insert_generic!($($scalar)+): $crate::ScalarRefValue<'__b>,
+                where
                     $crate::__juniper_insert_generic!($($scalar)+): 'r
                 {
                     // Ensure all child types are registered

juniper/src/macros/mod.rs

@@ -8,8 +8,6 @@ mod object;
 mod interface;
 #[macro_use]
 mod scalar;
-#[macro_use]
-mod union;
 
 #[cfg(test)]
 mod tests;

juniper/src/macros/object.rs

@@ -361,7 +361,7 @@ macro_rules! graphql_object {
                     info: &Self::TypeInfo,
                     registry: &mut $crate::Registry<'r, $crate::__juniper_insert_generic!($($scalar)+)>
                 ) -> $crate::meta::MetaType<'r, $crate::__juniper_insert_generic!($($scalar)+)>
-                where for<'__b> &'__b $crate::__juniper_insert_generic!($($scalar)+): $crate::ScalarRefValue<'__b>,
+                where
                     $crate::__juniper_insert_generic!($($scalar)+): 'r
                 {
                     let fields = &[$(

juniper/src/macros/scalar.rs

@@ -90,7 +90,7 @@ macro_rules! graphql_scalar {
                     info: &Self::TypeInfo,
                     registry: &mut $crate::Registry<'r, $crate::__juniper_insert_generic!($($scalar)+)>
                 ) -> $crate::meta::MetaType<'r, $crate::__juniper_insert_generic!($($scalar)+)>
-                where for<'__b> &'__b $crate::__juniper_insert_generic!($($scalar)+): $crate::ScalarRefValue<'__b>,
+                where
                     $crate::__juniper_insert_generic!($($scalar)+): 'r
                 {
                     let meta = registry.build_scalar_type::<Self>(info);
@@ -390,7 +390,7 @@ macro_rules! graphql_scalar {
                     info: &Self::TypeInfo,
                     registry: &mut $crate::Registry<'r, $crate::__juniper_insert_generic!($($scalar)+)>
                 ) -> $crate::meta::MetaType<'r, $crate::__juniper_insert_generic!($($scalar)+)>
-                where for<'__b> &'__b $crate::__juniper_insert_generic!($($scalar)+): $crate::ScalarRefValue<'__b>,
+                where
                     $crate::__juniper_insert_generic!($($scalar)+): 'r
                 {
                     let meta = registry.build_scalar_type::<Self>(info);

juniper/src/macros/tests/args.rs

@@ -73,17 +73,17 @@ impl Root {
         0
     }
 
-// TODO: enable once [parameter attributes are supported by proc macros]
+    // TODO: enable once [parameter attributes are supported by proc macros]
-//       (https://github.com/graphql-rust/juniper/pull/441)
+    //       (https://github.com/graphql-rust/juniper/pull/441)
-//     fn attr_arg_descr(
+    //     fn attr_arg_descr(
-//        #[graphql(description = "The arg")]
+    //        #[graphql(description = "The arg")]
-//        arg: i32) -> i32
+    //        arg: i32) -> i32
-//     { 0 }
+    //     { 0 }
-//    fn attr_arg_descr_collapse(
+    //    fn attr_arg_descr_collapse(
-//        #[graphql(description = "The first arg")]
+    //        #[graphql(description = "The first arg")]
-//        #[graphql(description = "and more details")]
+    //        #[graphql(description = "and more details")]
-//         arg: i32,
+    //         arg: i32,
-//     ) -> i32 { 0 }
+    //     ) -> i32 { 0 }
 
     #[graphql(arguments(arg(default = 123,),))]
     fn arg_with_default(arg: i32) -> i32 {

juniper/src/macros/tests/scalar.rs

@@ -27,7 +27,7 @@ graphql_scalar!(DefaultName where Scalar = <S> {
     }
 
     from_input_value(v: &InputValue) -> Option<DefaultName> {
-        v.as_scalar_value::<i32>().map(|i| DefaultName(*i))
+        v.as_scalar_value().and_then(|s| s.as_int()).map(|i| DefaultName(i))
     }
 
     from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {

juniper/src/macros/union.rs

@@ -1,143 +0,0 @@
-/*
- *
-/**
-Expose GraphQL unions
-
-Like interfaces, mapping unions can be tricky in idiomatic Rust. Because of
-their similarity, the helper macros are similar, too: you provide a set of
-expressions that resolve the union into the actual concrete type.
-
-## Syntax
-
-See the documentation for [`graphql_object!`][1] on the general item and type
-syntax. `graphql_union!` supports only `description` and `interface_resolvers`
-items, no fields or interfaces can be declared.
-
-See the documentation for [`graphql_interface!`][2] on the syntax for interface
-resolvers.
-
-[1]: macro.graphql_object!.html
-[2]: macro.graphql_interface!.html
-*/
-
-
-
-#[macro_export]
-macro_rules! graphql_union {
-
-    (
-        @generate,
-        meta = {
-            lifetimes = [$($lifetimes:tt,)*],
-            name = $name:ty,
-            ctx = $ctx:ty,
-            main_self = $main_self:ident,
-            outname = {$($outname:tt)*},
-            scalar = {$($scalar:tt)*},
-            $(description = $desciption:tt,)*
-            additional = {
-                resolver = {
-                    $(context = $resolver_ctx: ident,)*
-                    items = [
-                        $({
-                            src = $resolver_src: ty,
-                            resolver = $resolver_expr: expr,
-                        },)*
-                    ],
-                 },
-            },
-        },
-        items = [],
-    ) => {
-        $crate::__juniper_impl_trait!(
-            impl<$($scalar)* $(, $lifetimes)* > GraphQLType for $name {
-                type Context = $ctx;
-                type TypeInfo = ();
-
-                fn name(_ : &Self::TypeInfo) -> Option<&str> {
-                    Some($($outname)*)
-                }
-
-                fn meta<'r>(
-                    info: &Self::TypeInfo,
-                    registry: &mut $crate::Registry<'r, $crate::__juniper_insert_generic!($($scalar)+)>
-                ) -> $crate::meta::MetaType<'r, $crate::__juniper_insert_generic!($($scalar)+)>
-                where for<'__b> &'__b $crate::__juniper_insert_generic!($($scalar)+): $crate::ScalarRefValue<'__b>,
-                    $crate::__juniper_insert_generic!($($scalar)+): 'r
-                {
-                    let types = &[
-                        $(
-                          registry.get_type::<$resolver_src>(&()),
-                        )*
-                    ];
-                    registry.build_union_type::<$name>(
-                        info, types
-                    )
-                        $(.description($desciption))*
-                        .into_meta()
-                }
-
-                #[allow(unused_variables)]
-                fn concrete_type_name(&$main_self, context: &Self::Context, _info: &Self::TypeInfo) -> String {
-                    $(let $resolver_ctx = &context;)*
-
-                    $(
-                        if ($resolver_expr as ::std::option::Option<$resolver_src>).is_some() {
-                            return
-                                <$resolver_src as $crate::GraphQLType<_>>::name(&()).unwrap().to_owned();
-                        }
-                    )*
-
-                    panic!("Concrete type not handled by instance resolvers on {}", $($outname)*);
-                }
-
-                fn resolve_into_type(
-                    &$main_self,
-                    _info: &Self::TypeInfo,
-                    type_name: &str,
-                    _: Option<&[$crate::Selection<$crate::__juniper_insert_generic!($($scalar)*)>]>,
-                    executor: &$crate::Executor<Self::Context, $crate::__juniper_insert_generic!($($scalar)*)>,
-                ) -> $crate::ExecutionResult<$crate::__juniper_insert_generic!($($scalar)*)> {
-                    $(let $resolver_ctx = &executor.context();)*
-
-                    $(
-                        if type_name == (<$resolver_src as $crate::GraphQLType<_>>::name(&())).unwrap() {
-                            return executor.resolve(&(), &$resolver_expr);
-                        }
-                    )*
-
-                     panic!("Concrete type not handled by instance resolvers on {}", $($outname)*);
-                }
-            }
-        );
-    };
-
-
-    (
-        @parse,
-        meta = {$($meta:tt)*},
-        rest = $($rest:tt)*
-    ) => {
-        $crate::__juniper_parse_field_list!(
-            success_callback = graphql_union,
-            additional_parser = {
-                callback = __juniper_parse_instance_resolver,
-                header = {},
-            },
-            meta = {$($meta)*},
-            items = [],
-            rest = $($rest)*
-        );
-    };
-    (@$($stuff:tt)*) => {
-        compile_error!("Invalid syntax for `graphql_union!`");
-    };
-
-    ($($rest: tt)*) => {
-        $crate::__juniper_parse_object_header!(
-            callback = graphql_union,
-            rest = $($rest)*
-        );
-    };
-}
-*/

juniper/src/parser/tests/document.rs

@@ -6,13 +6,12 @@ use crate::{
     schema::model::SchemaType,
     types::scalars::EmptyMutation,
     validation::test_harness::{MutationRoot, QueryRoot},
-    value::{DefaultScalarValue, ScalarRefValue, ScalarValue},
+    value::{DefaultScalarValue, ScalarValue},
 };
 
 fn parse_document<S>(s: &str) -> Document<S>
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     parse_document_source(s, &SchemaType::new::<QueryRoot, MutationRoot>(&(), &()))
         .expect(&format!("Parse error on input {:#?}", s))
@@ -21,7 +20,6 @@ where
 fn parse_document_error<'a, S>(s: &'a str) -> Spanning<ParseError<'a>>
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     match parse_document_source::<S>(s, &SchemaType::new::<QueryRoot, MutationRoot>(&(), &())) {
         Ok(doc) => panic!("*No* parse error on input {:#?} =>\n{:#?}", s, doc),

juniper/src/parser/tests/value.rs

@@ -7,7 +7,7 @@ use juniper_codegen::{
 use crate::{
     ast::{FromInputValue, InputValue, Type},
     parser::{value::parse_value_literal, Lexer, Parser, SourcePosition, Spanning},
-    value::{DefaultScalarValue, ParseScalarValue, ScalarRefValue, ScalarValue},
+    value::{DefaultScalarValue, ParseScalarValue, ScalarValue},
 };
 
 use crate::{
@@ -72,7 +72,6 @@ where
 fn parse_value<S>(s: &str, meta: &MetaType<S>) -> Spanning<InputValue<S>>
 where
     S: ScalarValue,
-    for<'a> &'a S: ScalarRefValue<'a>,
 {
     let mut lexer = Lexer::new(s);
     let mut parser = Parser::new(&mut lexer).expect(&format!("Lexer error on input {:#?}", s));

juniper/src/schema/meta.rs

@@ -10,7 +10,7 @@ use crate::{
     parser::{ParseError, ScalarToken},
     schema::model::SchemaType,
     types::base::TypeKind,
-    value::{DefaultScalarValue, ParseScalarValue, ScalarRefValue, ScalarValue},
+    value::{DefaultScalarValue, ParseScalarValue, ScalarValue},
 };
 
 /// Whether an item is deprecated, with context.
@@ -395,7 +395,6 @@ where
     pub fn new<T>(name: Cow<'a, str>) -> Self
     where
         T: FromInputValue<S> + ParseScalarValue<S> + 'a,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         ScalarMeta {
             name,
@@ -491,7 +490,6 @@ where
     pub fn new<T>(name: Cow<'a, str>, values: &[EnumValue]) -> Self
     where
         T: FromInputValue<S>,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         EnumMeta {
             name,
@@ -575,9 +573,7 @@ where
 {
     /// Build a new input type with the specified name and input fields
     pub fn new<T: FromInputValue<S>>(name: Cow<'a, str>, input_fields: &[Argument<'a, S>]) -> Self
-    where
+where {
-        for<'b> &'b S: ScalarRefValue<'b>,
-    {
         InputObjectMeta {
             name,
             description: None,
@@ -765,7 +761,6 @@ impl<'a, S: fmt::Debug> fmt::Debug for InputObjectMeta<'a, S> {
 fn try_parse_fn<S, T>(v: &InputValue<S>) -> bool
 where
     T: FromInputValue<S>,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     <T as FromInputValue<S>>::from_input_value(v).is_some()
 }

juniper/src/schema/model.rs

@@ -9,7 +9,7 @@ use crate::{
     executor::{Context, Registry},
     schema::meta::{Argument, InterfaceMeta, MetaType, ObjectMeta, PlaceholderMeta, UnionMeta},
     types::{base::GraphQLType, name::Name},
-    value::{DefaultScalarValue, ScalarRefValue, ScalarValue},
+    value::{DefaultScalarValue, ScalarValue},
 };
 
 /// Root query node of a schema
@@ -20,7 +20,6 @@ use crate::{
 pub struct RootNode<'a, QueryT: GraphQLType<S>, MutationT: GraphQLType<S>, S = DefaultScalarValue>
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     #[doc(hidden)]
     pub query_type: QueryT,
@@ -80,16 +79,12 @@ where
     S: ScalarValue + 'a,
     QueryT: GraphQLType<S, TypeInfo = ()>,
     MutationT: GraphQLType<S, TypeInfo = ()>,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     /// Construct a new root node from query and mutation nodes
     ///
     /// If the schema should not support mutations, use the
     /// `new` constructor instead.
-    pub fn new(query_obj: QueryT, mutation_obj: MutationT) -> Self
+    pub fn new(query_obj: QueryT, mutation_obj: MutationT) -> Self {
-    where
-        for<'b> &'b S: ScalarRefValue<'b>,
-    {
         RootNode::new_with_info(query_obj, mutation_obj, (), ())
     }
 }
@@ -99,7 +94,6 @@ where
     QueryT: GraphQLType<S>,
     MutationT: GraphQLType<S>,
     S: ScalarValue + 'a,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     /// Construct a new root node from query and mutation nodes,
     /// while also providing type info objects for the query and
@@ -109,10 +103,7 @@ where
         mutation_obj: MutationT,
         query_info: QueryT::TypeInfo,
         mutation_info: MutationT::TypeInfo,
-    ) -> Self
+    ) -> Self {
-    where
-        for<'b> &'b S: ScalarRefValue<'b>,
-    {
         RootNode {
             query_type: query_obj,
             mutation_type: mutation_obj,
@@ -132,7 +123,6 @@ impl<'a, S> SchemaType<'a, S> {
         S: ScalarValue + 'a,
         QueryT: GraphQLType<S>,
         MutationT: GraphQLType<S>,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         let mut directives = FnvHashMap::default();
         let query_type_name: String;
@@ -425,7 +415,6 @@ where
     fn new_skip(registry: &mut Registry<'a, S>) -> DirectiveType<'a, S>
     where
         S: ScalarValue,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         Self::new(
             "skip",
@@ -441,7 +430,6 @@ where
     fn new_include(registry: &mut Registry<'a, S>) -> DirectiveType<'a, S>
     where
         S: ScalarValue,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         Self::new(
             "include",

juniper/src/schema/schema.rs

@@ -2,7 +2,7 @@ use crate::{
     ast::Selection,
     executor::{ExecutionResult, Executor, Registry},
     types::base::{Arguments, GraphQLType, TypeKind},
-    value::{ScalarRefValue, ScalarValue, Value},
+    value::{ScalarValue, Value},
 };
 
 use crate::schema::{
@@ -18,7 +18,6 @@ where
     S: ScalarValue,
     QueryT: GraphQLType<S, Context = CtxT>,
     MutationT: GraphQLType<S, Context = CtxT>,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = CtxT;
     type TypeInfo = QueryT::TypeInfo;
@@ -30,7 +29,6 @@ where
     fn meta<'r>(info: &QueryT::TypeInfo, registry: &mut Registry<'r, S>) -> MetaType<'r, S>
     where
         S: 'r,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         QueryT::meta(info, registry)
     }
@@ -86,7 +84,6 @@ where
     MutationT: crate::GraphQLTypeAsync<S, Context = CtxT>,
     MutationT::TypeInfo: Send + Sync,
     CtxT: Send + Sync,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     fn resolve_field_async<'b>(
         &'b self,

juniper/src/tests/type_info_tests.rs

@@ -7,7 +7,7 @@ use crate::{
         base::{Arguments, GraphQLType},
         scalars::EmptyMutation,
     },
-    value::{ScalarRefValue, ScalarValue, Value},
+    value::{ScalarValue, Value},
 };
 
 pub struct NodeTypeInfo {
@@ -22,7 +22,6 @@ pub struct Node {
 impl<S> GraphQLType<S> for Node
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = NodeTypeInfo;

juniper/src/types/async_await.rs

@@ -1,6 +1,6 @@
 use crate::{
     ast::{Directive, FromInputValue, InputValue, Selection},
-    value::{Object, ScalarRefValue, ScalarValue, Value},
+    value::{Object, ScalarValue, Value},
 };
 
 use crate::{
@@ -17,7 +17,6 @@ where
     Self::Context: Send + Sync,
     Self::TypeInfo: Send + Sync,
     S: ScalarValue + Send + Sync,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     fn resolve_field_async<'a>(
         &'a self,
@@ -75,7 +74,6 @@ where
     S: ScalarValue + Send + Sync,
     CtxT: Send + Sync,
     'e: 'a,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     Box::pin(resolve_selection_set_into_async_recursive(
         instance,
@@ -107,7 +105,6 @@ where
     T::TypeInfo: Send + Sync,
     S: ScalarValue + Send + Sync,
     CtxT: Send + Sync,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     use futures::stream::{FuturesOrdered, StreamExt};
 

juniper/src/types/base.rs

@@ -5,7 +5,7 @@ use juniper_codegen::GraphQLEnumInternal as GraphQLEnum;
 use crate::{
     ast::{Directive, FromInputValue, InputValue, Selection},
     executor::Variables,
-    value::{DefaultScalarValue, Object, ScalarRefValue, ScalarValue, Value},
+    value::{DefaultScalarValue, Object, ScalarValue, Value},
 };
 
 use crate::{
@@ -116,7 +116,6 @@ where
     pub fn get<T>(&self, key: &str) -> Option<T>
     where
         T: FromInputValue<S>,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         match self.args {
             Some(ref args) => match args.get(key) {
@@ -238,7 +237,6 @@ impl GraphQLType for User
 pub trait GraphQLType<S = DefaultScalarValue>: Sized
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     /// The expected context type for this GraphQL type
     ///
@@ -353,7 +351,6 @@ pub(crate) fn resolve_selection_set_into<T, CtxT, S>(
 where
     T: GraphQLType<S, Context = CtxT>,
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     let meta_type = executor
         .schema()
@@ -505,7 +502,6 @@ pub(super) fn is_excluded<S>(
 ) -> bool
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     if let Some(ref directives) = *directives {
         for &Spanning {

juniper/src/types/containers.rs

@@ -1,7 +1,7 @@
 use crate::{
     ast::{FromInputValue, InputValue, Selection, ToInputValue},
     schema::meta::MetaType,
-    value::{ScalarRefValue, ScalarValue, Value},
+    value::{ScalarValue, Value},
 };
 
 use crate::{
@@ -13,7 +13,6 @@ impl<S, T, CtxT> GraphQLType<S> for Option<T>
 where
     S: ScalarValue,
     T: GraphQLType<S, Context = CtxT>,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = CtxT;
     type TypeInfo = T::TypeInfo;
@@ -25,7 +24,6 @@ where
     fn meta<'r>(info: &T::TypeInfo, registry: &mut Registry<'r, S>) -> MetaType<'r, S>
     where
         S: 'r,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         registry.build_nullable_type::<T>(info).into_meta()
     }
@@ -48,10 +46,7 @@ where
     T: FromInputValue<S>,
     S: ScalarValue,
 {
-    fn from_input_value<'a>(v: &'a InputValue<S>) -> Option<Option<T>>
+    fn from_input_value<'a>(v: &'a InputValue<S>) -> Option<Option<T>> {
-    where
-        for<'b> &'b S: ScalarRefValue<'b>,
-    {
         match v {
             &InputValue::Null => Some(None),
             v => match v.convert() {
@@ -79,7 +74,6 @@ impl<S, T, CtxT> GraphQLType<S> for Vec<T>
 where
     T: GraphQLType<S, Context = CtxT>,
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = CtxT;
     type TypeInfo = T::TypeInfo;
@@ -91,7 +85,6 @@ where
     fn meta<'r>(info: &T::TypeInfo, registry: &mut Registry<'r, S>) -> MetaType<'r, S>
     where
         S: 'r,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         registry.build_list_type::<T>(info).into_meta()
     }
@@ -112,9 +105,7 @@ where
     S: ScalarValue,
 {
     fn from_input_value<'a>(v: &'a InputValue<S>) -> Option<Vec<T>>
-    where
+where {
-        for<'b> &'b S: ScalarRefValue<'b>,
-    {
         match *v {
             InputValue::List(ref ls) => {
                 let v: Vec<_> = ls.iter().filter_map(|i| i.item.convert()).collect();
@@ -150,7 +141,6 @@ impl<'a, S, T, CtxT> GraphQLType<S> for &'a [T]
 where
     S: ScalarValue,
     T: GraphQLType<S, Context = CtxT>,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = CtxT;
     type TypeInfo = T::TypeInfo;
@@ -162,7 +152,6 @@ where
     fn meta<'r>(info: &T::TypeInfo, registry: &mut Registry<'r, S>) -> MetaType<'r, S>
     where
         S: 'r,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         registry.build_list_type::<T>(info).into_meta()
     }
@@ -196,7 +185,6 @@ where
     S: ScalarValue,
     I: Iterator<Item = T> + ExactSizeIterator,
     T: GraphQLType<S>,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     let stop_on_null = executor
         .current_type()
@@ -230,7 +218,6 @@ where
     T: crate::GraphQLTypeAsync<S>,
     T::TypeInfo: Send + Sync,
     T::Context: Send + Sync,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     use futures::stream::{FuturesOrdered, StreamExt};
     use std::iter::FromIterator;
@@ -263,7 +250,6 @@ where
     T::TypeInfo: Send + Sync,
     S: ScalarValue + Send + Sync,
     CtxT: Send + Sync,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     fn resolve_async<'a>(
         &'a self,
@@ -283,7 +269,6 @@ where
     T::TypeInfo: Send + Sync,
     S: ScalarValue + Send + Sync,
     CtxT: Send + Sync,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     fn resolve_async<'a>(
         &'a self,
@@ -303,7 +288,6 @@ where
     T::TypeInfo: Send + Sync,
     S: ScalarValue + Send + Sync,
     CtxT: Send + Sync,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     fn resolve_async<'a>(
         &'a self,

juniper/src/types/pointers.rs

@@ -5,14 +5,13 @@ use crate::{
     executor::{ExecutionResult, Executor, Registry},
     schema::meta::MetaType,
     types::base::{Arguments, GraphQLType},
-    value::{ScalarRefValue, ScalarValue, Value},
+    value::{ScalarValue, Value},
 };
 
 impl<S, T, CtxT> GraphQLType<S> for Box<T>
 where
     S: ScalarValue,
     T: GraphQLType<S, Context = CtxT>,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = CtxT;
     type TypeInfo = T::TypeInfo;
@@ -24,7 +23,6 @@ where
     fn meta<'r>(info: &T::TypeInfo, registry: &mut Registry<'r, S>) -> MetaType<'r, S>
     where
         S: 'r,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         T::meta(info, registry)
     }
@@ -64,10 +62,7 @@ where
     S: ScalarValue,
     T: FromInputValue<S>,
 {
-    fn from_input_value<'a>(v: &'a InputValue<S>) -> Option<Box<T>>
+    fn from_input_value<'a>(v: &'a InputValue<S>) -> Option<Box<T>> {
-    where
-        for<'b> &'b S: ScalarRefValue<'b>,
-    {
         match <T as FromInputValue<S>>::from_input_value(v) {
             Some(v) => Some(Box::new(v)),
             None => None,
@@ -89,7 +84,6 @@ impl<'e, S, T, CtxT> GraphQLType<S> for &'e T
 where
     S: ScalarValue,
     T: GraphQLType<S, Context = CtxT>,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = CtxT;
     type TypeInfo = T::TypeInfo;
@@ -101,7 +95,6 @@ where
     fn meta<'r>(info: &T::TypeInfo, registry: &mut Registry<'r, S>) -> MetaType<'r, S>
     where
         S: 'r,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         T::meta(info, registry)
     }
@@ -143,7 +136,6 @@ where
     T: crate::GraphQLTypeAsync<S>,
     T::TypeInfo: Send + Sync,
     T::Context: Send + Sync,
-    for<'c> &'c S: ScalarRefValue<'c>,
 {
     fn resolve_field_async<'b>(
         &'b self,
@@ -179,7 +171,6 @@ impl<S, T> GraphQLType<S> for Arc<T>
 where
     S: ScalarValue,
     T: GraphQLType<S>,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = T::Context;
     type TypeInfo = T::TypeInfo;
@@ -191,7 +182,6 @@ where
     fn meta<'r>(info: &T::TypeInfo, registry: &mut Registry<'r, S>) -> MetaType<'r, S>
     where
         S: 'r,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         T::meta(info, registry)
     }

juniper/src/types/scalars.rs

@@ -7,7 +7,7 @@ use crate::{
     parser::{LexerError, ParseError, ScalarToken, Token},
     schema::meta::MetaType,
     types::base::GraphQLType,
-    value::{ParseScalarResult, ScalarRefValue, ScalarValue, Value},
+    value::{ParseScalarResult, ScalarValue, Value},
 };
 
 /// An ID as defined by the GraphQL specification
@@ -169,7 +169,6 @@ where
 impl<'a, S> GraphQLType<S> for &'a str
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -181,7 +180,6 @@ where
     fn meta<'r>(_: &(), registry: &mut Registry<'r, S>) -> MetaType<'r, S>
     where
         S: 'r,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         registry.build_scalar_type::<String>(&()).into_meta()
     }
@@ -200,7 +198,6 @@ where
 impl<'e, S> crate::GraphQLTypeAsync<S> for &'e str
 where
     S: ScalarValue + Send + Sync,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     fn resolve_async<'a>(
         &'a self,
@@ -314,7 +311,6 @@ unsafe impl<T> Send for EmptyMutation<T> {}
 impl<S, T> GraphQLType<S> for EmptyMutation<T>
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = T;
     type TypeInfo = ();
@@ -326,7 +322,6 @@ where
     fn meta<'r>(_: &(), registry: &mut Registry<'r, S>) -> MetaType<'r, S>
     where
         S: 'r,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         registry.build_object_type::<Self>(&(), &[]).into_meta()
     }
@@ -340,7 +335,6 @@ where
     Self::TypeInfo: Send + Sync,
     Self::Context: Send + Sync,
     T: Send + Sync,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
 }
 

juniper/src/validation/input_value.rs

@@ -9,7 +9,7 @@ use crate::{
         model::{SchemaType, TypeType},
     },
     validation::RuleError,
-    value::{ScalarRefValue, ScalarValue},
+    value::ScalarValue,
 };
 
 #[derive(Debug)]
@@ -26,7 +26,6 @@ pub fn validate_input_values<S>(
 ) -> Vec<RuleError>
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     let mut errs = vec![];
 
@@ -49,7 +48,6 @@ fn validate_var_defs<S>(
     errors: &mut Vec<RuleError>,
 ) where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     for &(ref name, ref def) in var_defs.iter() {
         let raw_type_name = def.var_type.item.innermost_name();
@@ -91,7 +89,6 @@ fn unify_value<'a, S>(
 ) -> Vec<RuleError>
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     let mut errors: Vec<RuleError> = vec![];
 
@@ -222,12 +219,13 @@ fn unify_enum<'a, S>(
 ) -> Vec<RuleError>
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     let mut errors: Vec<RuleError> = vec![];
+
     match *value {
-        InputValue::Scalar(ref scalar) if scalar.is_type::<String>() => {
+        // TODO: avoid this bad duplicate as_str() call. (value system refactor)
-            if let Some(ref name) = <&S as Into<Option<&String>>>::into(scalar) {
+        InputValue::Scalar(ref scalar) if scalar.as_str().is_some() => {
+            if let Some(ref name) = scalar.as_str() {
                 if !meta.values.iter().any(|ev| &ev.name == *name) {
                     errors.push(unification_error(
                         var_name,
@@ -268,7 +266,6 @@ fn unify_input_object<'a, S>(
 ) -> Vec<RuleError>
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     let mut errors: Vec<RuleError> = vec![];
 

juniper/src/validation/rules/overlapping_fields_can_be_merged.rs

@@ -752,7 +752,7 @@ mod tests {
             expect_fails_rule, expect_fails_rule_with_schema, expect_passes_rule,
             expect_passes_rule_with_schema, RuleError,
         },
-        value::{DefaultScalarValue, ScalarRefValue, ScalarValue},
+        value::{DefaultScalarValue, ScalarValue},
     };
 
     #[test]
@@ -1379,7 +1379,6 @@ mod tests {
     impl<S> GraphQLType<S> for SomeBox
     where
         S: ScalarValue,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         type Context = ();
         type TypeInfo = ();
@@ -1405,7 +1404,6 @@ mod tests {
     impl<S> GraphQLType<S> for StringBox
     where
         S: ScalarValue,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         type Context = ();
         type TypeInfo = ();
@@ -1437,7 +1435,6 @@ mod tests {
     impl<S> GraphQLType<S> for IntBox
     where
         S: ScalarValue,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         type Context = ();
         type TypeInfo = ();
@@ -1469,7 +1466,6 @@ mod tests {
     impl<S> GraphQLType<S> for NonNullStringBox1
     where
         S: ScalarValue,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         type Context = ();
         type TypeInfo = ();
@@ -1491,7 +1487,6 @@ mod tests {
     impl<S> GraphQLType<S> for NonNullStringBox1Impl
     where
         S: ScalarValue,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         type Context = ();
         type TypeInfo = ();
@@ -1523,7 +1518,6 @@ mod tests {
     impl<S> GraphQLType<S> for NonNullStringBox2
     where
         S: ScalarValue,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         type Context = ();
         type TypeInfo = ();
@@ -1545,7 +1539,6 @@ mod tests {
     impl<S> GraphQLType<S> for NonNullStringBox2Impl
     where
         S: ScalarValue,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         type Context = ();
         type TypeInfo = ();
@@ -1577,7 +1570,6 @@ mod tests {
     impl<S> GraphQLType<S> for Node
     where
         S: ScalarValue,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         type Context = ();
         type TypeInfo = ();
@@ -1602,7 +1594,6 @@ mod tests {
     impl<S> GraphQLType<S> for Edge
     where
         S: ScalarValue,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         type Context = ();
         type TypeInfo = ();
@@ -1624,7 +1615,6 @@ mod tests {
     impl<S> GraphQLType<S> for Connection
     where
         S: ScalarValue,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         type Context = ();
         type TypeInfo = ();
@@ -1646,7 +1636,6 @@ mod tests {
     impl<S> GraphQLType<S> for QueryRoot
     where
         S: ScalarValue,
-        for<'b> &'b S: ScalarRefValue<'b>,
     {
         type Context = ();
         type TypeInfo = ();

juniper/src/validation/test_harness.rs

@@ -10,7 +10,7 @@ use crate::{
     },
     types::{base::GraphQLType, scalars::ID},
     validation::{visit, MultiVisitorNil, RuleError, ValidatorContext, Visitor},
-    value::{ScalarRefValue, ScalarValue},
+    value::ScalarValue,
 };
 
 struct Being;
@@ -68,7 +68,6 @@ struct ComplexInput {
 impl<S> GraphQLType<S> for Being
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -92,7 +91,6 @@ where
 impl<S> GraphQLType<S> for Pet
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -116,7 +114,6 @@ where
 impl<S> GraphQLType<S> for Canine
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -140,7 +137,6 @@ where
 impl<S> GraphQLType<S> for DogCommand
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -170,10 +166,7 @@ impl<S> FromInputValue<S> for DogCommand
 where
     S: ScalarValue,
 {
-    fn from_input_value<'a>(v: &InputValue<S>) -> Option<DogCommand>
+    fn from_input_value<'a>(v: &InputValue<S>) -> Option<DogCommand> {
-    where
-        for<'b> &'b S: ScalarRefValue<'b>,
-    {
         match v.as_enum_value() {
             Some("SIT") => Some(DogCommand::Sit),
             Some("HEEL") => Some(DogCommand::Heel),
@@ -186,7 +179,6 @@ where
 impl<S> GraphQLType<S> for Dog
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -232,7 +224,6 @@ where
 impl<S> GraphQLType<S> for FurColor
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -263,12 +254,7 @@ impl<S> FromInputValue<S> for FurColor
 where
     S: ScalarValue,
 {
-    fn from_input_value<'a>(v: &InputValue<S>) -> Option<FurColor>
+    fn from_input_value<'a>(v: &InputValue<S>) -> Option<FurColor> {
-    where
-        //        S: 'a,
-        //        &'a S: ScalarRefValue<'a>,
-        for<'b> &'b S: ScalarRefValue<'b>,
-    {
         match v.as_enum_value() {
             Some("BROWN") => Some(FurColor::Brown),
             Some("BLACK") => Some(FurColor::Black),
@@ -282,7 +268,6 @@ where
 impl<S> GraphQLType<S> for Cat
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -315,7 +300,6 @@ where
 impl<S> GraphQLType<S> for CatOrDog
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -337,7 +321,6 @@ where
 impl<S> GraphQLType<S> for Intelligent
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -359,7 +342,6 @@ where
 impl<S> GraphQLType<S> for Human
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -393,7 +375,6 @@ where
 impl<S> GraphQLType<S> for Alien
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -427,7 +408,6 @@ where
 impl<S> GraphQLType<S> for DogOrHuman
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -449,7 +429,6 @@ where
 impl<S> GraphQLType<S> for HumanOrAlien
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -471,7 +450,6 @@ where
 impl<S> GraphQLType<S> for ComplexInput
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -502,11 +480,7 @@ impl<S> FromInputValue<S> for ComplexInput
 where
     S: ScalarValue,
 {
-    fn from_input_value<'a>(v: &InputValue<S>) -> Option<ComplexInput>
+    fn from_input_value<'a>(v: &InputValue<S>) -> Option<ComplexInput> {
-    where
-        for<'b> &'b S: ScalarRefValue<'b>, //        S: 'a,
-                                           //        &'a S: ScalarRefValue<'a>
-    {
         let obj = match v.to_object_value() {
             Some(o) => o,
             None => return None,
@@ -528,7 +502,6 @@ where
 impl<S> GraphQLType<S> for ComplicatedArgs
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -592,7 +565,6 @@ where
 impl<S> GraphQLType<S> for QueryRoot
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -626,7 +598,6 @@ where
 impl<S> GraphQLType<S> for MutationRoot
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     type Context = ();
     type TypeInfo = ();
@@ -656,7 +627,6 @@ where
 
 pub fn validate<'a, Q, M, V, F, S>(r: Q, m: M, q: &'a str, factory: F) -> Vec<RuleError>
 where
-    for<'b> &'b S: ScalarRefValue<'b>,
     S: ScalarValue + 'a,
     Q: GraphQLType<S, TypeInfo = ()>,
     M: GraphQLType<S, TypeInfo = ()>,
@@ -709,7 +679,6 @@ where
 pub fn expect_passes_rule<'a, V, F, S>(factory: F, q: &'a str)
 where
     S: ScalarValue + 'a,
-    for<'b> &'b S: ScalarRefValue<'b>,
     V: Visitor<'a, S> + 'a,
     F: Fn() -> V,
 {
@@ -719,7 +688,6 @@ where
 pub fn expect_passes_rule_with_schema<'a, Q, M, V, F, S>(r: Q, m: M, factory: F, q: &'a str)
 where
     S: ScalarValue + 'a,
-    for<'b> &'b S: ScalarRefValue<'b>,
     Q: GraphQLType<S, TypeInfo = ()>,
     M: GraphQLType<S, TypeInfo = ()>,
     V: Visitor<'a, S> + 'a,
@@ -736,7 +704,6 @@ where
 pub fn expect_fails_rule<'a, V, F, S>(factory: F, q: &'a str, expected_errors: &[RuleError])
 where
     S: ScalarValue + 'a,
-    for<'b> &'b S: ScalarRefValue<'b>,
     V: Visitor<'a, S> + 'a,
     F: Fn() -> V,
 {
@@ -751,7 +718,6 @@ pub fn expect_fails_rule_with_schema<'a, Q, M, V, F, S>(
     expected_errors: &[RuleError],
 ) where
     S: ScalarValue + 'a,
-    for<'b> &'b S: ScalarRefValue<'b>,
     Q: GraphQLType<S, TypeInfo = ()>,
     M: GraphQLType<S, TypeInfo = ()>,
     V: Visitor<'a, S> + 'a,

juniper/src/value/mod.rs

@@ -7,9 +7,7 @@ mod scalar;
 
 pub use self::object::Object;
 
-pub use self::scalar::{
+pub use self::scalar::{DefaultScalarValue, ParseScalarResult, ParseScalarValue, ScalarValue};
-    DefaultScalarValue, ParseScalarResult, ParseScalarValue, ScalarRefValue, ScalarValue,
-};
 
 /// Serializable value returned from query and field execution.
 ///
@@ -104,12 +102,12 @@ where
     }
 
     /// View the underlying float value, if present.
-    #[deprecated(since = "0.11.0", note = "Use `Value::as_scalar_value` instead")]
     pub fn as_float_value(&self) -> Option<f64>
-    where
+where {
-        for<'a> &'a S: ScalarRefValue<'a>,
+        match self {
-    {
+            Value::Scalar(ref s) => s.as_float(),
-        self.as_scalar_value::<f64>().cloned()
+            _ => None,
+        }
     }
 
     /// View the underlying object value, if present.
@@ -155,7 +153,6 @@ where
     }
 
     /// View the underlying string value, if present.
-    #[deprecated(since = "0.11.0", note = "Use `Value::as_scalar_value` instead")]
     pub fn as_string_value<'a>(&'a self) -> Option<&'a str>
     where
         Option<&'a String>: From<&'a S>,

juniper/src/value/scalar.rs

@@ -63,6 +63,13 @@ pub trait ParseScalarValue<S = DefaultScalarValue> {
 ///        }
 ///    }
 ///
+///    fn as_str(&self) -> Option<&str> {
+///        match *self {
+///            MyScalarValue::String(ref s) => Some(s.as_str()),
+///            _ => None,
+///        }
+///    }
+///
 ///    fn as_float(&self) -> Option<f64> {
 ///        match *self {
 ///            MyScalarValue::Int(ref i) => Some(*i as f64),
@@ -157,19 +164,7 @@ pub trait ParseScalarValue<S = DefaultScalarValue> {
 /// # fn main() {}
 /// ```
 pub trait ScalarValue:
-    Debug
+    Debug + Display + PartialEq + Clone + Serialize + From<String> + From<bool> + From<i32> + From<f64>
-    + Display
-    + PartialEq
-    + Clone
-    + Serialize
-    + From<String>
-    + From<bool>
-    + From<i32>
-    + From<f64>
-    + Into<Option<bool>>
-    + Into<Option<i32>>
-    + Into<Option<f64>>
-    + Into<Option<String>>
 {
     /// Serde visitor used to deserialize this scalar value
     type Visitor: for<'de> de::Visitor<'de, Value = Self> + Default;
@@ -206,6 +201,12 @@ pub trait ScalarValue:
     /// scalar values
     fn as_string(&self) -> Option<String>;
 
+    /// Convert the given scalar value into a string value
+    ///
+    /// This function is used for implementing `GraphQLType` for `String` for all
+    /// scalar values
+    fn as_str(&self) -> Option<&str>;
+
     /// Convert the given scalar value into a float value
     ///
     /// This function is used for implementing `GraphQLType` for `f64` for all
@@ -221,33 +222,6 @@ pub trait ScalarValue:
     fn as_boolean(&self) -> Option<bool>;
 }
 
-/// A marker trait extending the [`ScalarValue`](../trait.ScalarValue.html) trait
-///
-/// This trait should not be relied on directly by most apps.  However, you may
-/// need a where clause in the form of `for<'b> &'b S: ScalarRefValue<'b>` to
-/// abstract over different scalar value types.
-///
-/// This is automatically implemented for a type as soon as the type implements
-/// `ScalarValue` and the additional conversations.
-pub trait ScalarRefValue<'a>:
-    Debug
-    + Into<Option<&'a bool>>
-    + Into<Option<&'a i32>>
-    + Into<Option<&'a String>>
-    + Into<Option<&'a f64>>
-{
-}
-
-impl<'a, T> ScalarRefValue<'a> for &'a T
-where
-    T: ScalarValue,
-    &'a T: Into<Option<&'a bool>>
-        + Into<Option<&'a i32>>
-        + Into<Option<&'a String>>
-        + Into<Option<&'a f64>>,
-{
-}
-
 /// The default scalar value representation in juniper
 ///
 /// This types closely follows the graphql specification.
@@ -270,13 +244,6 @@ impl ScalarValue for DefaultScalarValue {
         }
     }
 
-    fn as_string(&self) -> Option<String> {
-        match *self {
-            DefaultScalarValue::String(ref s) => Some(s.clone()),
-            _ => None,
-        }
-    }
-
     fn as_float(&self) -> Option<f64> {
         match *self {
             DefaultScalarValue::Int(ref i) => Some(*i as f64),
@@ -285,6 +252,20 @@ impl ScalarValue for DefaultScalarValue {
         }
     }
 
+    fn as_str(&self) -> Option<&str> {
+        match *self {
+            DefaultScalarValue::String(ref s) => Some(s.as_str()),
+            _ => None,
+        }
+    }
+
+    fn as_string(&self) -> Option<String> {
+        match *self {
+            DefaultScalarValue::String(ref s) => Some(s.clone()),
+            _ => None,
+        }
+    }
+
     fn as_boolean(&self) -> Option<bool> {
         match *self {
             DefaultScalarValue::Boolean(ref b) => Some(*b),

juniper_codegen/src/derive_enum.rs

@@ -211,7 +211,6 @@ pub fn impl_enum(ast: &syn::DeriveInput, is_internal: bool) -> TokenStream {
         impl<__S> #juniper_path::GraphQLTypeAsync<__S> for #ident
             where
                 __S: #juniper_path::ScalarValue + Send + Sync,
-                for<'__b> &'__b __S: #juniper_path::ScalarRefValue<'__b>
         {
             fn resolve_async<'a>(
                 &'a self,
@@ -234,7 +233,6 @@ pub fn impl_enum(ast: &syn::DeriveInput, is_internal: bool) -> TokenStream {
         impl<__S> #juniper_path::GraphQLType<__S> for #ident
         where __S:
             #juniper_path::ScalarValue,
-            for<'__b> &'__b __S: #juniper_path::ScalarRefValue<'__b>
         {
             type Context = ();
             type TypeInfo = ();
@@ -268,10 +266,9 @@ pub fn impl_enum(ast: &syn::DeriveInput, is_internal: bool) -> TokenStream {
 
         impl<__S: #juniper_path::ScalarValue> #juniper_path::FromInputValue<__S> for #ident {
             fn from_input_value(v: &#juniper_path::InputValue<__S>) -> Option<#ident>
-                where for<'__b> &'__b __S: #juniper_path::ScalarRefValue<'__b>
             {
                 match v.as_enum_value().or_else(|| {
-                    v.as_scalar_value::<String>().map(|s| s as &str)
+                    v.as_string_value()
                 }) {
                     #from_inputs
                     _ => None,

juniper_codegen/src/derive_input_object.rs

@@ -157,6 +157,25 @@ pub fn impl_input_object(ast: &syn::DeriveInput, is_internal: bool) -> TokenStre
     let mut from_inputs = TokenStream::new();
     let mut to_inputs = TokenStream::new();
 
+    let (_, ty_generics, _) = generics.split_for_impl();
+
+    let mut generics = generics.clone();
+
+    let scalar = if let Some(scalar) = attrs.scalar {
+        scalar
+    } else {
+        generics.params.push(parse_quote!(__S));
+        {
+            let where_clause = generics.where_clause.get_or_insert(parse_quote!(where));
+            where_clause
+                .predicates
+                .push(parse_quote!(__S: #juniper_path::ScalarValue));
+        }
+        Ident::new("__S", Span::call_site())
+    };
+
+    let (impl_generics, _, where_clause) = generics.split_for_impl();
+
     for field in fields {
         let field_ty = &field.ty;
         let field_attrs = ObjFieldAttrs::from_input(field);
@@ -241,7 +260,7 @@ pub fn impl_input_object(ast: &syn::DeriveInput, is_internal: bool) -> TokenStre
                     #from_input_default
                     Some(ref v) => #juniper_path::FromInputValue::from_input_value(v).unwrap(),
                     None => {
-                        #juniper_path::FromInputValue::from_input_value(&#juniper_path::InputValue::null())
+                        #juniper_path::FromInputValue::from_input_value(&#juniper_path::InputValue::<#scalar>::null())
                             .unwrap()
                     },
                 }
@@ -254,28 +273,6 @@ pub fn impl_input_object(ast: &syn::DeriveInput, is_internal: bool) -> TokenStre
         });
     }
 
-    let (_, ty_generics, _) = generics.split_for_impl();
-
-    let mut generics = generics.clone();
-
-    let scalar = if let Some(scalar) = attrs.scalar {
-        scalar
-    } else {
-        generics.params.push(parse_quote!(__S));
-        {
-            let where_clause = generics.where_clause.get_or_insert(parse_quote!(where));
-            where_clause
-                .predicates
-                .push(parse_quote!(__S: #juniper_path::ScalarValue));
-            where_clause
-                .predicates
-                .push(parse_quote!(for<'__b> &'__b __S: #juniper_path::ScalarRefValue<'__b>));
-        }
-        Ident::new("__S", Span::call_site())
-    };
-
-    let (impl_generics, _, where_clause) = generics.split_for_impl();
-
     let body = quote! {
         impl#impl_generics #juniper_path::GraphQLType<#scalar> for #ident #ty_generics
         #where_clause
@@ -306,8 +303,6 @@ pub fn impl_input_object(ast: &syn::DeriveInput, is_internal: bool) -> TokenStre
         #where_clause
         {
             fn from_input_value(value: &#juniper_path::InputValue<#scalar>) -> Option<Self>
-            where
-                for<'__b> &'__b #scalar: #juniper_path::ScalarRefValue<'__b>
             {
                 if let Some(obj) = value.to_object_value() {
                     let item = #ident {

juniper_codegen/src/derive_scalar_value.rs

@@ -114,7 +114,6 @@ fn impl_scalar_struct(
         impl<S> #crate_name::GraphQLType<S> for #ident
         where
             S: #crate_name::ScalarValue,
-            for<'__b> &'__b S: #crate_name::ScalarRefValue<'__b>,
         {
             type Context = ();
             type TypeInfo = ();
@@ -128,7 +127,6 @@ fn impl_scalar_struct(
                 registry: &mut #crate_name::Registry<'r, S>,
             ) -> #crate_name::meta::MetaType<'r, S>
             where
-                for<'__b> &'__b S: #crate_name::ScalarRefValue<'__b>,
                 S: 'r,
             {
                 registry.build_scalar_type::<Self>(info)
@@ -149,7 +147,6 @@ fn impl_scalar_struct(
         impl<S> #crate_name::ToInputValue<S> for #ident
         where
             S: #crate_name::ScalarValue,
-            for<'__b> &'__b S: #crate_name::ScalarRefValue<'__b>,
         {
             fn to_input_value(&self) -> #crate_name::InputValue<S> {
                 #crate_name::ToInputValue::to_input_value(&self.0)
@@ -159,7 +156,6 @@ fn impl_scalar_struct(
         impl<S> #crate_name::FromInputValue<S> for #ident
         where
             S: #crate_name::ScalarValue,
-            for<'__b> &'__b S: #crate_name::ScalarRefValue<'__b>,
         {
             fn from_input_value(v: &#crate_name::InputValue<S>) -> Option<#ident> {
                 let inner: #inner_ty = #crate_name::FromInputValue::from_input_value(v)?;
@@ -170,7 +166,6 @@ fn impl_scalar_struct(
         impl<S> #crate_name::ParseScalarValue<S> for #ident
         where
             S: #crate_name::ScalarValue,
-            for<'__b> &'__b S: #crate_name::ScalarRefValue<'__b>,
         {
             fn from_str<'a>(
                 value: #crate_name::parser::ScalarToken<'a>,

juniper_codegen/src/impl_union.rs

@@ -132,19 +132,7 @@ pub fn impl_union(
         .map(|s| quote!( #s ))
         .unwrap_or_else(|| { quote! { #juniper::DefaultScalarValue } });
 
-    let mut generics = item.generics.clone();
+    let generics = item.generics.clone();
-    if attrs.scalar.is_some() {
-        // A custom scalar type was specified.
-        // Therefore, we always insert a where clause that marks the scalar as
-        // compatible with ScalarValueRef.
-        // This is done to prevent the user from having to specify this
-        // manually.
-        let where_clause = generics.where_clause.get_or_insert(syn::parse_quote!(where));
-        where_clause.predicates.push(
-            syn::parse_quote!(for<'__b> &'__b #scalar: #juniper::ScalarRefValue<'__b>),
-        );
-    }
-
     let (impl_generics, _, where_clause) = generics.split_for_impl();
 
     let description = match attrs.description.as_ref() {
@@ -168,7 +156,6 @@ pub fn impl_union(
                 registry: &mut #juniper::Registry<'r, #scalar>
             ) -> #juniper::meta::MetaType<'r, #scalar>
                 where
-                    for<'__b> &'__b #scalar: #juniper::ScalarRefValue<'__b>,
                     #scalar: 'r,
             {
                 let types = &[

juniper_codegen/src/util.rs

@@ -809,15 +809,6 @@ impl GraphQLTypeDefiniton {
         let mut generics = self.generics.clone();
 
         if self.scalar.is_some() {
-            // A custom scalar type was specified.
-            // Therefore, we always insert a where clause that marks the scalar as
-            // compatible with ScalarValueRef.
-            // This is done to prevent the user from having to specify this
-            // manually.
-            let where_clause = generics.where_clause.get_or_insert(parse_quote!(where));
-            where_clause.predicates.push(
-                parse_quote!(for<'__b> &'__b #scalar: #juniper_crate_name::ScalarRefValue<'__b>),
-            );
         } else if self.generic_scalar {
             // No custom scalar specified, but always generic specified.
             // Therefore we inject the generic scalar.
@@ -829,12 +820,6 @@ impl GraphQLTypeDefiniton {
             where_clause
                 .predicates
                 .push(parse_quote!(__S: #juniper_crate_name::ScalarValue));
-            // Insert a where clause that marks the scalar as
-            // compatible with ScalarValueRef.
-            // Same as in branch above.
-            where_clause
-                .predicates
-                .push(parse_quote!(for<'__b> &'__b __S: #juniper_crate_name::ScalarRefValue<'__b>));
         }
 
         let type_generics_tokens = if self.include_type_generics {
@@ -976,7 +961,6 @@ impl GraphQLTypeDefiniton {
                     registry: &mut #juniper_crate_name::Registry<'r, #scalar>
                 ) -> #juniper_crate_name::meta::MetaType<'r, #scalar>
                     where #scalar : 'r,
-                    for<'z> &'z #scalar: #juniper_crate_name::ScalarRefValue<'z>,
                 {
                     let fields = vec![
                         #( #field_definitions ),*

juniper_hyper/src/lib.rs

@@ -11,7 +11,7 @@ use hyper::{
 };
 use juniper::{
     http::GraphQLRequest as JuniperGraphQLRequest, serde::Deserialize, DefaultScalarValue,
-    GraphQLType, InputValue, RootNode, ScalarRefValue, ScalarValue,
+    GraphQLType, InputValue, RootNode, ScalarValue,
 };
 use serde_json::error::Error as SerdeError;
 use std::{error::Error, fmt, string::FromUtf8Error, sync::Arc};
@@ -25,7 +25,6 @@ pub fn graphql<CtxT, QueryT, MutationT, S>(
 ) -> impl Future<Item = Response<Body>, Error = hyper::Error>
 where
     S: ScalarValue + Send + Sync + 'static,
-    for<'b> &'b S: ScalarRefValue<'b>,
     CtxT: Send + Sync + 'static,
     QueryT: GraphQLType<S, Context = CtxT> + Send + Sync + 'static,
     MutationT: GraphQLType<S, Context = CtxT> + Send + Sync + 'static,
@@ -111,7 +110,6 @@ fn execute_request<CtxT, QueryT, MutationT, S>(
 ) -> impl Future<Item = Response<Body>, Error = tokio_threadpool::BlockingError>
 where
     S: ScalarValue + Send + Sync + 'static,
-    for<'b> &'b S: ScalarRefValue<'b>,
     CtxT: Send + Sync + 'static,
     QueryT: GraphQLType<S, Context = CtxT> + Send + Sync + 'static,
     MutationT: GraphQLType<S, Context = CtxT> + Send + Sync + 'static,
@@ -212,7 +210,6 @@ where
 impl<S> GraphQLRequest<S>
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     fn execute<'a, CtxT: 'a, QueryT, MutationT>(
         self,

juniper_iron/src/lib.rs

@@ -119,7 +119,7 @@ use serde_json::error::Error as SerdeError;
 
 use juniper::{
     http, serde::Deserialize, DefaultScalarValue, GraphQLType, InputValue, RootNode,
-    ScalarRefValue, ScalarValue,
+    ScalarValue,
 };
 
 #[derive(serde_derive::Deserialize)]
@@ -146,7 +146,6 @@ where
 impl<S> GraphQLBatchRequest<S>
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     pub fn execute<'a, CtxT, QueryT, MutationT>(
         &'a self,
@@ -198,7 +197,6 @@ where
 pub struct GraphQLHandler<'a, CtxFactory, Query, Mutation, CtxT, S = DefaultScalarValue>
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
     CtxFactory: Fn(&mut Request) -> IronResult<CtxT> + Send + Sync + 'static,
     CtxT: 'static,
     Query: GraphQLType<S, Context = CtxT> + Send + Sync + 'static,
@@ -253,7 +251,6 @@ impl<'a, CtxFactory, Query, Mutation, CtxT, S>
     GraphQLHandler<'a, CtxFactory, Query, Mutation, CtxT, S>
 where
     S: ScalarValue + 'a,
-    for<'b> &'b S: ScalarRefValue<'b>,
     CtxFactory: Fn(&mut Request) -> IronResult<CtxT> + Send + Sync + 'static,
     CtxT: 'static,
     Query: GraphQLType<S, Context = CtxT, TypeInfo = ()> + Send + Sync + 'static,
@@ -340,7 +337,6 @@ impl<'a, CtxFactory, Query, Mutation, CtxT, S> Handler
     for GraphQLHandler<'a, CtxFactory, Query, Mutation, CtxT, S>
 where
     S: ScalarValue + Sync + Send + 'static,
-    for<'b> &'b S: ScalarRefValue<'b>,
     CtxFactory: Fn(&mut Request) -> IronResult<CtxT> + Send + Sync + 'static,
     CtxT: 'static,
     Query: GraphQLType<S, Context = CtxT, TypeInfo = ()> + Send + Sync + 'static,

juniper_rocket/src/lib.rs

@@ -54,7 +54,7 @@ use rocket::{
 use juniper::{http, InputValue};
 
 use juniper::{
-    serde::Deserialize, DefaultScalarValue, FieldError, GraphQLType, RootNode, ScalarRefValue,
+    serde::Deserialize, DefaultScalarValue, FieldError, GraphQLType, RootNode, 
     ScalarValue,
 };
 
@@ -88,7 +88,6 @@ where
 impl<S> GraphQLBatchRequest<S>
 where
     S: ScalarValue + Send + Sync,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     pub fn execute<'a, CtxT, QueryT, MutationT>(
         &'a self,
@@ -192,7 +191,6 @@ pub fn playground_source(graphql_endpoint_url: &str) -> content::Html<String> {
 impl<S> GraphQLRequest<S>
 where
     S: ScalarValue + Sync + Send,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     /// Execute an incoming GraphQL query
     pub fn execute<CtxT, QueryT, MutationT>(

juniper_warp/src/lib.rs

@@ -48,7 +48,7 @@ use warp::{filters::BoxedFilter, Filter};
 #[cfg(feature = "async")]
 use futures03::future::{FutureExt, TryFutureExt};
 
-use juniper::{DefaultScalarValue, InputValue, ScalarRefValue, ScalarValue};
+use juniper::{DefaultScalarValue, InputValue, ScalarValue};
 
 #[derive(Debug, serde_derive::Deserialize, PartialEq)]
 #[serde(untagged)]
@@ -64,7 +64,6 @@ where
 impl<S> GraphQLBatchRequest<S>
 where
     S: ScalarValue,
-    for<'b> &'b S: ScalarRefValue<'b>,
 {
     pub fn execute<'a, CtxT, QueryT, MutationT>(
         &'a self,
@@ -210,7 +209,6 @@ pub fn make_graphql_filter<Query, Mutation, Context, S>(
 ) -> BoxedFilter<(warp::http::Response<Vec<u8>>,)>
 where
     S: ScalarValue + Send + Sync + 'static,
-    for<'b> &'b S: ScalarRefValue<'b>,
     Context: Send + 'static,
     Query: juniper::GraphQLType<S, Context = Context, TypeInfo = ()> + Send + Sync + 'static,
     Mutation: juniper::GraphQLType<S, Context = Context, TypeInfo = ()> + Send + Sync + 'static,
@@ -283,7 +281,6 @@ pub fn make_graphql_filter_async<Query, Mutation, Context, S>(
 ) -> BoxedFilter<(warp::http::Response<Vec<u8>>,)>
 where
     S: ScalarValue + Send + Sync + 'static,
-    for<'b> &'b S: ScalarRefValue<'b>,
     Context: Send + Sync + 'static,
     Query: juniper::GraphQLTypeAsync<S, Context = Context> + Send + Sync + 'static,
     Query::TypeInfo: Send + Sync,