From 6d6868dcd3ef0f2c781c7e55f66fdc8036a5f7d2 Mon Sep 17 00:00:00 2001
From: janis <janis@nirgendwo.xyz>
Date: Mon, 22 Sep 2025 14:56:27 +0200
Subject: [PATCH] fix reflect type paths with generic lifetimes

---
 crates/bevy_reflect/derive/src/derive_data.rs | 14 +++++++-------
 crates/bevy_reflect/src/lib.rs                | 13 ++++++++++++-
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/crates/bevy_reflect/derive/src/derive_data.rs b/crates/bevy_reflect/derive/src/derive_data.rs
index 826b225debbcb..9b831951af079 100644
--- a/crates/bevy_reflect/derive/src/derive_data.rs
+++ b/crates/bevy_reflect/derive/src/derive_data.rs
@@ -1238,17 +1238,17 @@ impl<'a> ReflectTypePath<'a> {
         mut ty_generic_fn: impl FnMut(&TypeParam) -> StringExpr,
         bevy_reflect_path: &Path,
     ) -> StringExpr {
-        let mut params = generics.params.iter().filter_map(|param| match param {
-            GenericParam::Type(type_param) => Some(ty_generic_fn(type_param)),
+        let mut params = generics.params.iter().map(|param| match param {
+            GenericParam::Type(type_param) => ty_generic_fn(type_param),
             GenericParam::Const(const_param) => {
                 let ident = &const_param.ident;
                 let ty = &const_param.ty;
 
-                Some(StringExpr::Owned(quote! {
+                StringExpr::Owned(quote! {
                     <#ty as #bevy_reflect_path::__macro_exports::alloc_utils::ToString>::to_string(&#ident)
-                }))
+                })
             }
-            GenericParam::Lifetime(_) => None,
+            GenericParam::Lifetime(_) => StringExpr::from_str("'_"),
         });
 
         params
@@ -1269,7 +1269,7 @@ impl<'a> ReflectTypePath<'a> {
                 let ident = self.type_ident().unwrap();
                 let module_path = self.module_path().unwrap();
 
-                if self.impl_is_generic() {
+                if !generics.params.is_empty() {
                     let generics = ReflectTypePath::reduce_generics(
                         generics,
                         |TypeParam { ident, .. }| {
@@ -1307,7 +1307,7 @@ impl<'a> ReflectTypePath<'a> {
             Self::External { generics, .. } | Self::Internal { generics, .. } => {
                 let ident = self.type_ident().unwrap();
 
-                if self.impl_is_generic() {
+                if !generics.params.is_empty() {
                     let generics = ReflectTypePath::reduce_generics(
                         generics,
                         |TypeParam { ident, .. }| {
diff --git a/crates/bevy_reflect/src/lib.rs b/crates/bevy_reflect/src/lib.rs
index 359b8aaad3b03..a9e888be5f3d2 100644
--- a/crates/bevy_reflect/src/lib.rs
+++ b/crates/bevy_reflect/src/lib.rs
@@ -2130,7 +2130,18 @@ mod tests {
             (Type,) => "(Long,)", "(Short,)",
             (Type, Type) => "(Long, Long)", "(Short, Short)",
             (Type, Type, Type) => "(Long, Long, Long)", "(Short, Short, Short)",
-            Cow<'static, Type> => "alloc::borrow::Cow<Long>", "Cow<Short>",
+            Cow<'static, Type> => "alloc::borrow::Cow<'_, Long>", "Cow<'_, Short>",
+        }
+
+        #[expect(
+            dead_code,
+            reason = "field 0 carries the lifetime which is used in the type path"
+        )]
+        #[derive(TypePath)]
+        struct WithLifetime<'a>(&'a ());
+
+        assert_type_paths! {
+            WithLifetime<'static> => "bevy_reflect::tests::WithLifetime<'_>", "WithLifetime<'_>",
         }
     }