Look inside of None-delimited groups when examining types

serde_derive/src/bound.rs

@@ -5,7 +5,7 @@ use syn::punctuated::{Pair, Punctuated};
 use syn::visit::{self, Visit};
 
 use internals::ast::{Container, Data};
-use internals::attr;
+use internals::{attr, ungroup};
 
 use proc_macro2::Span;
 
@@ -114,7 +114,7 @@ pub fn with_bound(
     }
     impl<'ast> Visit<'ast> for FindTyParams<'ast> {
         fn visit_field(&mut self, field: &'ast syn::Field) {
-            if let syn::Type::Path(ty) = &field.ty {
+            if let syn::Type::Path(ty) = ungroup(&field.ty) {
                 if let Some(Pair::Punctuated(t, _)) = ty.path.segments.pairs().next() {
                     if self.all_type_params.contains(&t.ident) {
                         self.associated_type_usage.push(ty);