Try #207:

godot-codegen/src/class_generator.rs

@@ -988,11 +988,63 @@ fn make_virtual_method(class_method: &ClassMethod, ctx: &mut Context) -> TokenSt
     // Virtual methods are never static.
     assert!(!class_method.is_static);
 
-    let receiver = make_receiver_self_param(false, class_method.is_const);
-    let [params, _, _, _] = make_params(&class_method.arguments, class_method.is_vararg, ctx);
+    let [params, variant_types, _, arg_names] =
+        make_params(&class_method.arguments, class_method.is_vararg, ctx);
+
+    let is_varcall = class_method.is_vararg;
+    let variant_ffi = is_varcall.then(VariantFfi::type_ptr);
+    let (receiver, receiver_arg) = make_receiver(
+        class_method.is_static,
+        class_method.is_const,
+        quote! { self.object_ptr },
+    );
+    let varcall_invocation = quote! {
+        __call_fn(__method_bind, #receiver_arg, __args_ptr, __args.len() as i64, return_ptr, std::ptr::addr_of_mut!(__err));
+    };
+    let ptrcall_invocation = quote! {
+        __call_fn(__method_bind, #receiver_arg, __args_ptr, return_ptr);
+    };
+
+    let (prepare_arg_types, error_fn_context);
+    if variant_ffi.is_some() {
+        // varcall (using varargs)
+        prepare_arg_types = quote! {
+            let mut __arg_types = Vec::with_capacity(__explicit_args.len() + varargs.len());
+            // __arg_types.extend(__explicit_args.iter().map(Variant::get_type));
+            __arg_types.extend(varargs.iter().map(Variant::get_type));
+            let __vararg_str = varargs.iter().map(|v| format!("{v}")).collect::<Vec<_>>().join(", ");
+        };
+
+        let joined = arg_names
+            .iter()
+            .map(|n| format!("{{{n}:?}}"))
+            .collect::<Vec<_>>()
+            .join(", ");
+
+        let fmt = format!("{method_name}({joined}; {{__vararg_str}})");
+        error_fn_context = quote! { &format!(#fmt) };
+    } else {
+        // ptrcall
+        prepare_arg_types = quote! {
+            let __arg_types = [
+                #( #variant_types ),*
+            ];
+        };
+        error_fn_context = method_name.to_token_stream();
+    };
+
+    let (return_value, _) = make_return(
+        class_method.return_value.as_ref(),
+        variant_ffi.as_ref(),
+        &varcall_invocation,
+        &ptrcall_invocation,
+        prepare_arg_types,
+        error_fn_context,
+        ctx,
+    );
 
     quote! {
-        fn #method_name ( #receiver #( #params , )* ) {
+        fn #method_name ( #receiver #( #params , )* ) #return_value {
           unimplemented!()
         }
     }

itest/rust/src/virtual_methods_test.rs

@@ -10,8 +10,9 @@ use crate::TestContext;
 use godot::bind::{godot_api, GodotClass};
 use godot::builtin::GodotString;
 use godot::engine::node::InternalMode;
-use godot::engine::{Node, Node2D, Node2DVirtual, RefCounted, RefCountedVirtual};
+use godot::engine::{Node, Node2D, Node2DVirtual, NodeVirtual, RefCounted, RefCountedVirtual};
 use godot::obj::{Base, Gd, Share};
+use godot::prelude::PackedStringArray;
 use godot::test::itest;
 
 /// Simple class, that deliberately has no constructor accessible from GDScript
@@ -91,6 +92,26 @@ impl Node2DVirtual for TreeVirtualTest {
     }
 }
 
+#[derive(GodotClass, Debug)]
+#[class(base=Node)]
+struct ReturnVirtualTest {
+    #[base]
+    base: Base<Node>,
+}
+
+#[godot_api]
+impl NodeVirtual for ReturnVirtualTest {
+    fn init(base: Base<Node>) -> Self {
+        ReturnVirtualTest { base }
+    }
+
+    fn get_configuration_warnings(&self) -> PackedStringArray {
+        let mut output = PackedStringArray::new();
+        output.push("Hello".into());
+        output
+    }
+}
+
 // ----------------------------------------------------------------------------------------------------------------------------------------------
 
 #[itest]
@@ -215,3 +236,11 @@ fn test_tree_enters_exits(test_context: &TestContext) {
     assert_eq!(obj.bind().tree_enters, 2);
     assert_eq!(obj.bind().tree_exits, 1);
 }
+
+#[itest]
+fn test_virtual_method_with_return(_test_context: &TestContext) {
+    let obj = Gd::<ReturnVirtualTest>::new_default();
+    let output = obj.bind().get_configuration_warnings();
+    assert!(output.contains("Hello".into()));
+    assert_eq!(output.len(), 1);
+}