derive: less tokenstream conversion

miniconf_derive/src/lib.rs

@@ -9,49 +9,56 @@ use tree::Tree;
 #[proc_macro_derive(TreeKey, attributes(tree))]
 pub fn derive_tree_key(input: TokenStream) -> TokenStream {
     match Tree::parse(&parse_macro_input!(input as DeriveInput)) {
-        Ok(t) => t.tree_key().into(),
-        Err(e) => e.write_errors().into(),
+        Ok(t) => t.tree_key(),
+        Err(e) => e.write_errors(),
     }
+    .into()
 }
 
 /// Derive the `TreeSerialize` trait for a struct.
 #[proc_macro_derive(TreeSerialize, attributes(tree))]
 pub fn derive_tree_serialize(input: TokenStream) -> TokenStream {
     match Tree::parse(&parse_macro_input!(input as DeriveInput)) {
-        Ok(t) => t.tree_serialize().into(),
-        Err(e) => e.write_errors().into(),
+        Ok(t) => t.tree_serialize(),
+        Err(e) => e.write_errors(),
     }
+    .into()
 }
 
 /// Derive the `TreeDeserialize` trait for a struct.
 #[proc_macro_derive(TreeDeserialize, attributes(tree))]
 pub fn derive_tree_deserialize(input: TokenStream) -> TokenStream {
     match Tree::parse(&parse_macro_input!(input as DeriveInput)) {
-        Ok(t) => t.tree_deserialize().into(),
-        Err(e) => e.write_errors().into(),
+        Ok(t) => t.tree_deserialize(),
+        Err(e) => e.write_errors(),
     }
+    .into()
 }
 
 /// Derive the `TreeAny` trait for a struct.
 #[proc_macro_derive(TreeAny, attributes(tree))]
 pub fn derive_tree_any(input: TokenStream) -> TokenStream {
     match Tree::parse(&parse_macro_input!(input as DeriveInput)) {
-        Ok(t) => t.tree_any().into(),
-        Err(e) => e.write_errors().into(),
+        Ok(t) => t.tree_any(),
+        Err(e) => e.write_errors(),
     }
+    .into()
 }
 
 /// Shorthand to derive the `TreeKey`, `TreeAny`, `TreeSerialize`, and `TreeDeserialize` traits for a struct.
 #[proc_macro_derive(Tree, attributes(tree))]
 pub fn derive_tree(input: TokenStream) -> TokenStream {
     match Tree::parse(&parse_macro_input!(input as DeriveInput)) {
-        Ok(t) => {
-            let mut ts: TokenStream = t.tree_key().into();
-            ts.extend(TokenStream::from(t.tree_any()));
-            ts.extend(TokenStream::from(t.tree_serialize()));
-            ts.extend(TokenStream::from(t.tree_deserialize()));
-            ts
-        }
-        Err(e) => e.write_errors().into(),
+        Ok(t) => [
+            t.tree_key(),
+            t.tree_any(),
+            t.tree_serialize(),
+            t.tree_deserialize(),
+        ]
+        .into_iter()
+        .flatten()
+        .collect(),
+        Err(e) => e.write_errors(),
     }
+    .into()
 }