support dynamized supertraits via attribute

1 files changed, 22 insertions, 4 deletions

diff --git a/src/lib.rs b/src/lib.rs
index f8fdde8..017a58b 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -83,6 +83,15 @@ pub fn dynamize(_attr: TokenStream, input: TokenStream) -> TokenStream {
         Err(err) => return err.to_compile_error().into(),
     };
 
+    for dyn_supertrait in &method_attrs.dynamized_supertraits {
+        if !trait_bounds(&original_trait.supertraits).any(|t| t.path.is_ident(dyn_supertrait)) {
+            return abort!(
+                dyn_supertrait.span(),
+                "this trait definition has no such supertrait"
+            );
+        }
+    }
+
     let mut type_converter = TypeConverter {
         collections: method_attrs.collections,
         assoc_type_conversions: HashMap::new(),
@@ -185,11 +194,20 @@ pub fn dynamize(_attr: TokenStream, input: TokenStream) -> TokenStream {
         supertraits: original_trait
             .supertraits
             .iter()
-            .filter(|t| match t {
-                TypeParamBound::Trait(t) => !t.path.is_ident("Sized"),
-                TypeParamBound::Lifetime(_) => true,
+            .filter_map(|t| {
+                if let TypeParamBound::Trait(trait_bound) = t {
+                    if let Some(ident) = trait_bound.path.get_ident() {
+                        if ident == "Sized" {
+                            return None;
+                        } else if method_attrs.dynamized_supertraits.contains(ident) {
+                            let mut bound = trait_bound.clone();
+                            bound.path.segments[0].ident = format_ident!("Dyn{}", ident);
+                            return Some(TypeParamBound::Trait(bound));
+                        }
+                    }
+                }
+                Some(t.clone())
             })
-            .cloned()
             .collect(),
         brace_token: Brace::default(),
         items: Vec::new(),