support Self qualified as same trait

1 files changed, 20 insertions, 7 deletions

diff --git a/src/transform.rs b/src/transform.rs
index eed48c4..75138c9 100644
--- a/src/transform.rs
+++ b/src/transform.rs
@@ -14,10 +14,10 @@ use crate::{
     trait_sig::{MethodError, TypeTransform},
 };
 
-#[derive(Default)]
 pub struct TypeConverter<'a> {
     pub assoc_type_conversions: HashMap<Ident, DestType<'a>>,
     pub collections: HashMap<Ident, usize>,
+    pub trait_ident: Ident,
 }
 
 #[derive(Debug)]
@@ -27,7 +27,7 @@ pub enum TransformError {
     ExpectedAtLeastNTypes(usize),
     AssocTypeAfterFirstNTypes(usize, Ident),
     QualifiedAssociatedType,
-    QualifiedSelfAssociatedType,
+    SelfQualifiedAsOtherTrait,
 }
 
 impl TypeConverter<'_> {
@@ -115,7 +115,8 @@ impl TypeConverter<'_> {
         }
 
         if let Type::Path(TypePath {
-            qself: Some(qself), ..
+            path,
+            qself: Some(qself),
         }) = type_
         {
             if let Type::Path(self_path) = qself.ty.as_ref() {
@@ -123,10 +124,22 @@ impl TypeConverter<'_> {
                     if !self_path.path.is_ident("Self") {
                         return Err((self_path.span(), TransformError::QualifiedAssociatedType));
                     }
-                    return Err((
-                        self_path.span(),
-                        TransformError::QualifiedSelfAssociatedType,
-                    ));
+
+                    if qself.position == 1
+                        && path.segments.len() == 2
+                        && path.segments[0].arguments.is_empty()
+                        && path.segments[0].ident == self.trait_ident
+                    {
+                        let ident = &path.segments[1].ident;
+                        let dest_type =
+                            self.assoc_type_conversions.get(ident).ok_or_else(|| {
+                                (ident.span(), TransformError::AssocTypeWithoutDestType)
+                            })?;
+                        *type_ = dest_type.get_dest();
+                        return Ok(dest_type.type_transformation());
+                    }
+
+                    return Err((path.span(), TransformError::SelfQualifiedAsOtherTrait));
                 }
             }
         } else if let Type::Path(TypePath { path, qself: None }) = type_ {