diff --git a/tests/source/issue_4954.rs b/tests/source/issue_4954.rs
new file mode 100644
index 00000000000..8011c601b65
--- /dev/null
+++ b/tests/source/issue_4954.rs
@@ -0,0 +1,5 @@
+trait Foo {
+  type Arg<'a>;
+}
+
+struct Bar<T>(T) where for<'a> T: Foo<Arg<'a> = ()>;
diff --git a/tests/target/issue_4954.rs b/tests/target/issue_4954.rs
new file mode 100644
index 00000000000..aa5e79befe9
--- /dev/null
+++ b/tests/target/issue_4954.rs
@@ -0,0 +1,7 @@
+trait Foo {
+    type Arg<'a>;
+}
+
+struct Bar<T>(T)
+where
+    for<'a> T: Foo<Arg<'a> = ()>;