support Vec, VecDeque & LinkedList collections

5 files changed, 43 insertions, 1 deletions

diff --git a/README.md b/README.md
index 6b4d4e1..cf5d0c1 100644
--- a/README.md
+++ b/README.md
@@ -90,6 +90,7 @@ Dynamize also understands if you wrap associated types in the following types:
 * `Option<_>`
 * `Result<_, _>`
 * `some::module::Result<_>` (type alias with fixed error type)
+* `Vec<_>`, `VecDeque<_>`,`LinkedList<_>`
 * `&mut dyn Iterator<Item = _>`
 
 Note that since these are resolved recursively you can actually nest these
diff --git a/src/lib.rs b/src/lib.rs
index 1f75023..6a1708f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -409,7 +409,11 @@ impl TypeTransform {
                     quote! {#arg.map_err(|x| #err_inner)}
                 }
             }
-            _other => arg,
+            TypeTransform::Collection(inner) => {
+                let inner = inner.convert(quote!(x));
+                quote! {#arg.into_iter().map(|x| #inner).collect()}
+            }
+            TypeTransform::NoOp => arg,
         }
     }
 }
diff --git a/src/parse_trait_sig.rs b/src/parse_trait_sig.rs
index ab2c437..c924a71 100644
--- a/src/parse_trait_sig.rs
+++ b/src/parse_trait_sig.rs
@@ -17,6 +17,7 @@ pub enum TypeTransform {
     Into,
     Box(BoxType),
     Map(Box<TypeTransform>),
+    Collection(Box<TypeTransform>),
     Iterator(BoxType, Box<TypeTransform>),
     Result(Box<TypeTransform>, Box<TypeTransform>),
 }
diff --git a/src/transform.rs b/src/transform.rs
index e8481bb..3f1c313 100644
--- a/src/transform.rs
+++ b/src/transform.rs
@@ -22,6 +22,12 @@ pub enum TransformError {
     AssocTypeInUnsupportedType(Span),
 }
 
+fn is_supported_collection(ident: &Ident) -> bool {
+    // collections added here must implement IntoIterator & FromIterator
+    // FromIterator must not require bounds like Eq or Ord since these are Self-referential
+    ident == "Vec" || ident == "VecDeque" || ident == "LinkedList"
+}
+
 impl AssocTypeConversions<'_> {
     pub fn parse_type_path(&self, type_: &mut Type) -> Result<TypeTransform, TransformError> {
         if !iter_type(type_).any(match_assoc_type) {
@@ -120,6 +126,21 @@ impl AssocTypeConversions<'_> {
                         }
                     }
                 }
+            } else if is_supported_collection(ident) && path.segments.len() == 1 {
+                let first_seg = path.segments.first_mut().unwrap();
+
+                if let PathArguments::AngleBracketed(args) = &mut first_seg.arguments {
+                    if args.args.len() == 1 {
+                        if let GenericArgument::Type(generic_type) = args.args.first_mut().unwrap()
+                        {
+                            if iter_type(generic_type).any(match_assoc_type) {
+                                return Ok(TypeTransform::Collection(
+                                    self.parse_type_path(generic_type)?.into(),
+                                ));
+                            }
+                        }
+                    }
+                }
             } else {
                 let last_seg = &path.segments.last().unwrap();
                 if last_seg.ident == "Result" {
diff --git a/tests/tests.rs b/tests/tests.rs
index bae52bd..7801cfc 100644
--- a/tests/tests.rs
+++ b/tests/tests.rs
@@ -204,6 +204,21 @@ fn test3<T: TypeWithSuper>(some: T) {
     println!("{}", dyn_trait);
 }
 
+use std::collections::{LinkedList, VecDeque};
+
+#[dynamize::dynamize]
+trait Collections {
+    type A: std::error::Error;
+
+    fn vec(&self) -> Vec<Self::A>;
+
+    fn vec_deque(&self) -> VecDeque<Self::A>;
+
+    fn linked_list(&self) -> LinkedList<Self::A>;
+
+    fn vec_opt(&self) -> Vec<Option<Self::A>>;
+}
+
 #[dynamize::dynamize]
 trait ReturnIter {
     type A: std::error::Error;