Add support for "dyn" trait object syntax (#385)

* Use "dyn" for TraitObjects

* Cleanup after adding "dyn" support

* Add entry to CHANGELOG.md

juniper/CHANGELOG.md

@@ -18,6 +18,7 @@ struct UserId(i32);
 ### Other Changes
 
 - The `ID` scalar now implements Serde's `Serialize` and `Deserialize`
+- Add support for `dyn` trait object syntax to procedural macros
 
 # [[0.12.0] 2019-05-16](https://github.com/graphql-rust/juniper/releases/tag/juniper-0.12.0)
 

juniper/src/tests/model.rs

@@ -17,7 +17,7 @@ pub trait Character {
     fn friend_ids(&self) -> &[String];
     fn appears_in(&self) -> &[Episode];
     fn secret_backstory(&self) -> &Option<String>;
-    fn as_character(&self) -> &Character;
+    fn as_character(&self) -> &dyn Character;
 }
 
 pub trait Human: Character {
@@ -62,7 +62,7 @@ impl Character for HumanData {
     fn secret_backstory(&self) -> &Option<String> {
         &self.secret_backstory
     }
-    fn as_character(&self) -> &Character {
+    fn as_character(&self) -> &dyn Character {
         self
     }
 }
@@ -89,7 +89,7 @@ impl Character for DroidData {
     fn secret_backstory(&self) -> &Option<String> {
         &self.secret_backstory
     }
-    fn as_character(&self) -> &Character {
+    fn as_character(&self) -> &dyn Character {
         self
     }
 }
@@ -248,7 +248,7 @@ impl Database {
         }
     }
 
-    pub fn get_hero(&self, episode: Option<Episode>) -> &Character {
+    pub fn get_hero(&self, episode: Option<Episode>) -> &dyn Character {
         if episode == Some(Episode::Empire) {
             self.get_human("1000").unwrap().as_character()
         } else {
@@ -256,15 +256,15 @@ impl Database {
         }
     }
 
-    pub fn get_human(&self, id: &str) -> Option<&Human> {
-        self.humans.get(id).map(|h| h as &Human)
+    pub fn get_human(&self, id: &str) -> Option<&dyn Human> {
+        self.humans.get(id).map(|h| h as &dyn Human)
     }
 
-    pub fn get_droid(&self, id: &str) -> Option<&Droid> {
-        self.droids.get(id).map(|d| d as &Droid)
+    pub fn get_droid(&self, id: &str) -> Option<&dyn Droid> {
+        self.droids.get(id).map(|d| d as &dyn Droid)
     }
 
-    pub fn get_character(&self, id: &str) -> Option<&Character> {
+    pub fn get_character(&self, id: &str) -> Option<&dyn Character> {
         if let Some(h) = self.humans.get(id) {
             Some(h)
         } else if let Some(d) = self.droids.get(id) {
@@ -274,7 +274,7 @@ impl Database {
         }
     }
 
-    pub fn get_friends(&self, c: &Character) -> Vec<&Character> {
+    pub fn get_friends(&self, c: &dyn Character) -> Vec<&dyn Character> {
         c.friend_ids()
             .iter()
             .flat_map(|id| self.get_character(id))

juniper/src/tests/schema.rs

@@ -5,7 +5,7 @@ use crate::tests::model::{Character, Database, Droid, Episode, Human};
 
 impl Context for Database {}
 
-graphql_interface!(<'a> &'a Character: Database as "Character" |&self| {
+graphql_interface!(<'a> &'a dyn Character: Database as "Character" |&self| {
     description: "A character in the Star Wars Trilogy"
 
     field id() -> &str as "The id of the character" {
@@ -16,7 +16,7 @@ graphql_interface!(<'a> &'a Character: Database as "Character" |&self| {
         Some(self.name())
     }
 
-    field friends(&executor) -> Vec<&Character>
+    field friends(&executor) -> Vec<&dyn Character>
     as "The friends of the character" {
         executor.context().get_friends(self.as_character())
     }
@@ -26,8 +26,8 @@ graphql_interface!(<'a> &'a Character: Database as "Character" |&self| {
     }
 
     instance_resolvers: |&context| {
-        &Human => context.get_human(&self.id()),
-        &Droid => context.get_droid(&self.id()),
+        &dyn Human => context.get_human(&self.id()),
+        &dyn Droid => context.get_droid(&self.id()),
     }
 });
 
@@ -37,7 +37,7 @@ graphql_interface!(<'a> &'a Character: Database as "Character" |&self| {
     interfaces = [&dyn Character],
 )]
 /// A humanoid creature in the Star Wars universe.
-impl<'a> &'a Human {
+impl<'a> &'a dyn Human {
     /// The id of the human
     fn id(&self) -> &str {
         self.id()
@@ -49,7 +49,7 @@ impl<'a> &'a Human {
     }
 
     /// The friends of the human
-    fn friends(&self, ctx: &Database) -> Vec<&Character> {
+    fn friends(&self, ctx: &Database) -> Vec<&dyn Character> {
         ctx.get_friends(self.as_character())
     }
 
@@ -70,7 +70,7 @@ impl<'a> &'a Human {
     interfaces = [&dyn Character],
 )]
 /// A mechanical creature in the Star Wars universe.
-impl<'a> &'a Droid {
+impl<'a> &'a dyn Droid {
     /// The id of the droid
     fn id(&self) -> &str {
         self.id()
@@ -82,7 +82,7 @@ impl<'a> &'a Droid {
     }
 
     /// The friends of the droid
-    fn friends(&self, ctx: &Database) -> Vec<&Character> {
+    fn friends(&self, ctx: &Database) -> Vec<&dyn Character> {
         ctx.get_friends(self.as_character())
     }
 
@@ -106,19 +106,19 @@ pub struct Query;
 /// The root query object of the schema
 impl Query {
     #[graphql(arguments(id(description = "id of the human")))]
-    fn human(database: &Database, id: String) -> Option<&Human> {
+    fn human(database: &Database, id: String) -> Option<&dyn Human> {
         database.get_human(&id)
     }
 
     #[graphql(arguments(id(description = "id of the droid")))]
-    fn droid(database: &Database, id: String) -> Option<&Droid> {
+    fn droid(database: &Database, id: String) -> Option<&dyn Droid> {
         database.get_droid(&id)
     }
 
     #[graphql(arguments(episode(
         description = "If omitted, returns the hero of the whole saga. If provided, returns the hero of that particular episode"
     )))]
-    fn hero(database: &Database, episode: Option<Episode>) -> Option<&Character> {
+    fn hero(database: &Database, episode: Option<Episode>) -> Option<&dyn Character> {
         Some(database.get_hero(episode).as_character())
     }
 }

juniper_codegen/src/impl_object.rs

@@ -52,19 +52,23 @@ pub fn build_object(args: TokenStream, body: TokenStream, is_internal: bool) ->
                 .unwrap()
                 .ident
                 .to_string(),
-            syn::Type::Reference(ref reference) => match &*reference.elem {
-                syn::Type::Path(ref type_path) => type_path
-                    .path
-                    .segments
-                    .iter()
-                    .last()
-                    .unwrap()
-                    .ident
-                    .to_string(),
+            syn::Type::Reference(ref reference) => {
+                let path = match &*reference.elem {
+                    syn::Type::Path(ref type_path) => &type_path.path,
+                    syn::Type::TraitObject(ref trait_obj) => {
+                        match trait_obj.bounds.iter().nth(0).unwrap() {
+                            syn::TypeParamBound::Trait(ref trait_bound) => &trait_bound.path,
                             _ => {
                                 panic!("Could not determine a name for the object type: specify one with #[juniper::object(name = \"SomeName\")");
                             }
-            },
+                        }
+                    }
+                    _ => {
+                        panic!("Could not determine a name for the object type: specify one with #[juniper::object(name = \"SomeName\")");
+                    }
+                };
+                path.segments.iter().last().unwrap().ident.to_string()
+            }
             _ => {
                 panic!("Could not determine a name for the object type: specify one with #[juniper::object(name = \"SomeName\")");
             }

juniper_hyper/src/lib.rs

@@ -294,7 +294,7 @@ impl Error for GraphQLRequestError {
         }
     }
 
-    fn cause(&self) -> Option<&Error> {
+    fn cause(&self) -> Option<&dyn Error> {
         match *self {
             GraphQLRequestError::BodyHyper(ref err) => Some(err),
             GraphQLRequestError::BodyUtf8(ref err) => Some(err),

juniper_iron/src/lib.rs

@@ -416,7 +416,7 @@ impl Error for GraphQLIronError {
         }
     }
 
-    fn cause(&self) -> Option<&Error> {
+    fn cause(&self) -> Option<&dyn Error> {
         match *self {
             GraphQLIronError::Serde(ref err) => Some(err),
             GraphQLIronError::Url(ref err) => Some(err),