avm1: Remove `TObject::set_proto`

The last usage of it was in `Player`, which anyway should operate
only on newly created objects that don't have any virtual properties
nor watchers. So it is safe to replace with `define_value`, that
also cannot fail.

core/src/avm1/function.rs

@@ -684,14 +684,6 @@ impl<'gc> TObject<'gc> for FunctionObject<'gc> {
         self.base.proto(activation)
     }
 
-    fn set_proto(
-        &self,
-        activation: &mut Activation<'_, 'gc, '_>,
-        prototype: Value<'gc>,
-    ) -> Result<(), Error<'gc>> {
-        self.base.set_proto(activation, prototype)
-    }
-
     fn define_value(
         &self,
         gc_context: MutationContext<'gc, '_>,

core/src/avm1/object.rs

@@ -266,17 +266,6 @@ pub trait TObject<'gc>: 'gc + Collect + Debug + Into<Object<'gc>> + Clone + Copy
     /// `get`.
     fn proto(&self, activation: &mut Activation<'_, 'gc, '_>) -> Value<'gc>;
 
-    /// Sets the `__proto__` of a given object.
-    ///
-    /// The proto is another object used to resolve methods across a class of
-    /// multiple objects. It should also be accessible as `__proto__` in
-    /// `set`.
-    fn set_proto(
-        &self,
-        activation: &mut Activation<'_, 'gc, '_>,
-        prototype: Value<'gc>,
-    ) -> Result<(), Error<'gc>>;
-
     /// Define a value on an object.
     ///
     /// Unlike setting a value, this function is intended to replace any

core/src/avm1/object/array_object.rs

@@ -225,14 +225,6 @@ impl<'gc> TObject<'gc> for ArrayObject<'gc> {
         self.0.read().proto(activation)
     }
 
-    fn set_proto(
-        &self,
-        activation: &mut Activation<'_, 'gc, '_>,
-        prototype: Value<'gc>,
-    ) -> Result<(), Error<'gc>> {
-        self.0.read().set_proto(activation, prototype)
-    }
-
     fn has_property(&self, activation: &mut Activation<'_, 'gc, '_>, name: &str) -> bool {
         self.0.read().has_property(activation, name)
     }

core/src/avm1/object/custom_object.rs

@@ -97,14 +97,6 @@ macro_rules! impl_custom_object {
             self.0.read().$field.proto(activation)
         }
 
-        fn set_proto(
-            &self,
-            activation: &mut crate::avm1::Activation<'_, 'gc, '_>,
-            prototype: crate::avm1::Value<'gc>,
-        ) -> Result<(), crate::avm1::Error<'gc>> {
-            self.0.read().$field.set_proto(activation, prototype)
-        }
-
         fn define_value(
             &self,
             gc_context: gc_arena::MutationContext<'gc, '_>,

core/src/avm1/object/script_object.rs

@@ -439,14 +439,6 @@ impl<'gc> TObject<'gc> for ScriptObject<'gc> {
         self.get_data("__proto__", activation)
     }
 
-    fn set_proto(
-        &self,
-        activation: &mut Activation<'_, 'gc, '_>,
-        prototype: Value<'gc>,
-    ) -> Result<(), Error<'gc>> {
-        self.set_data("__proto__", prototype, activation)
-    }
-
     /// Checks if the object has a given named property.
     fn has_property(&self, activation: &mut Activation<'_, 'gc, '_>, name: &str) -> bool {
         self.has_own_property(activation, name)

core/src/avm1/object/stage_object.rs

@@ -273,14 +273,6 @@ impl<'gc> TObject<'gc> for StageObject<'gc> {
         self.0.read().base.proto(activation)
     }
 
-    fn set_proto(
-        &self,
-        activation: &mut Activation<'_, 'gc, '_>,
-        prototype: Value<'gc>,
-    ) -> Result<(), Error<'gc>> {
-        self.0.read().base.set_proto(activation, prototype)
-    }
-
     fn define_value(
         &self,
         gc_context: MutationContext<'gc, '_>,

core/src/avm1/object/super_object.rs

@@ -161,17 +161,6 @@ impl<'gc> TObject<'gc> for SuperObject<'gc> {
         self.0.read().base_proto.proto(activation)
     }
 
-    fn set_proto(
-        &self,
-        activation: &mut Activation<'_, 'gc, '_>,
-        prototype: Value<'gc>,
-    ) -> Result<(), Error<'gc>> {
-        if let Value::Object(prototype) = prototype {
-            self.0.write(activation.context.gc_context).base_proto = prototype;
-        }
-        Ok(())
-    }
-
     fn define_value(
         &self,
         _gc_context: MutationContext<'gc, '_>,

core/src/avm1/object/xml_attributes_object.rs

@@ -182,14 +182,6 @@ impl<'gc> TObject<'gc> for XmlAttributesObject<'gc> {
         self.base().proto(activation)
     }
 
-    fn set_proto(
-        &self,
-        activation: &mut Activation<'_, 'gc, '_>,
-        prototype: Value<'gc>,
-    ) -> Result<(), Error<'gc>> {
-        self.base().set_proto(activation, prototype)
-    }
-
     fn has_property(&self, activation: &mut Activation<'_, 'gc, '_>, name: &str) -> bool {
         self.base().has_property(activation, name)
     }

core/src/avm1/object/xml_idmap_object.rs

@@ -183,14 +183,6 @@ impl<'gc> TObject<'gc> for XmlIdMapObject<'gc> {
         self.base().proto(activation)
     }
 
-    fn set_proto(
-        &self,
-        activation: &mut Activation<'_, 'gc, '_>,
-        prototype: Value<'gc>,
-    ) -> Result<(), Error<'gc>> {
-        self.base().set_proto(activation, prototype)
-    }
-
     fn has_property(&self, activation: &mut Activation<'_, 'gc, '_>, name: &str) -> bool {
         self.base().has_property(activation, name)
     }

core/src/player.rs

@@ -1309,7 +1309,12 @@ impl Player {
                     );
                     if let Ok(prototype) = constructor.get("prototype", &mut activation) {
                         if let Value::Object(object) = actions.clip.object() {
-                            object.set_proto(&mut activation, prototype).unwrap(); // TODO: What happens on error?
+                            object.define_value(
+                                activation.context.gc_context,
+                                "__proto__",
+                                prototype,
+                                Attribute::empty(),
+                            );
                             for event in events {
                                 let _ = activation.run_child_frame_for_action(
                                     "[Actions]",