Add regression test for rust macro calls not prepended with &

testing/tests/let.rs

@@ -0,0 +1,23 @@
+use rinja::Template;
+
+#[derive(Template)]
+#[template(
+    source = r#"{%- let x -%}
+{%- if y -%}
+    {%- let x = String::new() %}
+{%- else -%}
+    {%- let x = format!("blob") %}
+{%- endif -%}
+{{ x }}"#,
+    ext = "html"
+)]
+struct A {
+    y: bool,
+}
+
+// This test ensures that rust macro calls in `let`/`set` statements are not prepended with `&`.
+#[test]
+fn let_macro() {
+    let template = A { y: false };
+    assert_eq!(template.render().unwrap(), "blob")
+}