also dynamize simple type param bounds in where clauses

1 files changed, 76 insertions, 39 deletions

diff --git a/src/transform.rs b/src/transform.rs
index 6640cf3..676cfd8 100644
--- a/src/transform.rs
+++ b/src/transform.rs
@@ -2,8 +2,8 @@ use std::collections::HashMap;
 
 use proc_macro2::Span;
 use syn::{
-    spanned::Spanned, GenericArgument, Generics, Ident, PathArguments, Type, TypeParamBound,
-    TypePath,
+    spanned::Spanned, GenericArgument, Generics, Ident, PathArguments, TraitBound, Type,
+    TypeParamBound, TypePath, WherePredicate,
 };
 
 use crate::{
@@ -112,51 +112,88 @@ pub fn dynamize_function_bounds(
     for type_param in generics.type_params_mut() {
         for bound in &mut type_param.bounds {
             if let TypeParamBound::Trait(bound) = bound {
-                if bound.path.segments.len() == 1 {
-                    let segment = bound.path.segments.first_mut().unwrap();
+                dynamize_trait_bound(
+                    bound,
+                    assoc_type_conversions,
+                    &type_param.ident,
+                    &mut type_param_transforms,
+                )?;
+            }
+        }
+    }
 
-                    if let PathArguments::Parenthesized(args) = &mut segment.arguments {
-                        if segment.ident == "Fn"
-                            || segment.ident == "FnOnce"
-                            || segment.ident == "FnMut"
-                        {
-                            let mut transforms = Vec::new();
-                            for input_type in &mut args.inputs {
-                                match assoc_type_conversions.parse_type_path(input_type) {
-                                    Ok(ret_type) => {
-                                        transforms.push(ret_type);
-                                    }
-                                    Err(TransformError::UnconvertibleAssocType(span)) => {
-                                        return Err((
-                                            span,
-                                            MethodParseError::UnconvertibleAssocType,
-                                        ));
-                                    }
-                                    Err(TransformError::AssocTypeInUnsupportedType(span)) => {
-                                        return Err((
-                                            span,
-                                            MethodParseError::UnconvertibleAssocTypeInFnInput,
-                                        ));
-                                    }
-                                }
-                            }
-                            if transforms.iter().any(|t| !matches!(t, TypeTransform::NoOp)) {
-                                type_param_transforms.insert(type_param.ident.clone(), transforms);
+    if let Some(where_clause) = &mut generics.where_clause {
+        for predicate in &mut where_clause.predicates {
+            if let WherePredicate::Type(predicate_type) = predicate {
+                if let Type::Path(path) = &mut predicate_type.bounded_ty {
+                    if let Some(ident) = path.path.get_ident() {
+                        for bound in &mut predicate_type.bounds {
+                            if let TypeParamBound::Trait(bound) = bound {
+                                dynamize_trait_bound(
+                                    bound,
+                                    assoc_type_conversions,
+                                    ident,
+                                    &mut type_param_transforms,
+                                )?;
                             }
                         }
+                        continue;
                     }
                 }
-                if let Some(path) = iter_path(&bound.path)
-                    .filter_map(filter_map_assoc_paths)
-                    .next()
-                {
-                    return Err((
-                        path.span(),
-                        MethodParseError::UnconvertibleAssocTypeInTraitBound,
-                    ));
+
+                // TODO: return error if predicate_type.bounded_ty contains associated type
+
+                for bound in &mut predicate_type.bounds {
+                    if let TypeParamBound::Trait(_bound) = bound {
+                        // TODO: return error if bound.path contains associated type
+                    }
                 }
             }
         }
     }
+
     Ok(type_param_transforms)
 }
+
+fn dynamize_trait_bound(
+    bound: &mut TraitBound,
+    assoc_type_conversions: &AssocTypeConversions,
+    type_ident: &Ident,
+    type_param_transforms: &mut HashMap<Ident, Vec<TypeTransform>>,
+) -> Result<(), (Span, MethodParseError)> {
+    if bound.path.segments.len() == 1 {
+        let segment = bound.path.segments.first_mut().unwrap();
+
+        if let PathArguments::Parenthesized(args) = &mut segment.arguments {
+            if segment.ident == "Fn" || segment.ident == "FnOnce" || segment.ident == "FnMut" {
+                let mut transforms = Vec::new();
+                for input_type in &mut args.inputs {
+                    match assoc_type_conversions.parse_type_path(input_type) {
+                        Ok(ret_type) => {
+                            transforms.push(ret_type);
+                        }
+                        Err(TransformError::UnconvertibleAssocType(span)) => {
+                            return Err((span, MethodParseError::UnconvertibleAssocType));
+                        }
+                        Err(TransformError::AssocTypeInUnsupportedType(span)) => {
+                            return Err((span, MethodParseError::UnconvertibleAssocTypeInFnInput));
+                        }
+                    }
+                }
+                if transforms.iter().any(|t| !matches!(t, TypeTransform::NoOp)) {
+                    type_param_transforms.insert(type_ident.clone(), transforms);
+                }
+            }
+        }
+    }
+    if let Some(path) = iter_path(&bound.path)
+        .filter_map(filter_map_assoc_paths)
+        .next()
+    {
+        return Err((
+            path.span(),
+            MethodParseError::UnconvertibleAssocTypeInTraitBound,
+        ));
+    }
+    Ok(())
+}