if first type bound isn't Into<T> auto-box it

1 files changed, 11 insertions, 2 deletions

diff --git a/src/syn_utils.rs b/src/syn_utils.rs
index 4588186..61ae27f 100644
--- a/src/syn_utils.rs
+++ b/src/syn_utils.rs
@@ -1,6 +1,6 @@
 use syn::{
-    punctuated::Punctuated, GenericArgument, Path, PathArguments, ReturnType, TraitBound, Type,
-    TypeParamBound,
+    punctuated::Punctuated, GenericArgument, Lifetime, Path, PathArguments, ReturnType, TraitBound,
+    Type, TypeParamBound,
 };
 
 pub trait TypeMatcher<T> {
@@ -21,6 +21,15 @@ pub fn trait_bounds<T>(
     })
 }
 
+pub fn lifetime_bounds<T>(
+    bounds: &Punctuated<TypeParamBound, T>,
+) -> impl Iterator<Item = &Lifetime> {
+    bounds.iter().filter_map(|b| match b {
+        TypeParamBound::Trait(_) => None,
+        TypeParamBound::Lifetime(l) => Some(l),
+    })
+}
+
 pub fn find_in_type<'a, T>(t: &'a Type, matcher: &dyn TypeMatcher<T>) -> Option<&'a T> {
     if let Some(ret) = matcher.match_type(t) {
         return Some(ret);