wip: props default this compat

packages/runtime-core/src/componentProps.ts

@@ -33,6 +33,7 @@ import {
 import { isEmitListener } from './componentEmits'
 import { InternalObjectKey } from './vnode'
 import { AppContext } from './apiCreateApp'
+import { createPropsDefaultThis } from './compat/props'
 
 export type ComponentPropsOptions<P = Data> =
   | ComponentObjectPropsOptions<P>
@@ -342,7 +343,10 @@ function resolvePropValue(
           value = propsDefaults[key]
         } else {
           setCurrentInstance(instance)
-          value = propsDefaults[key] = defaultValue(props)
+          value = propsDefaults[key] =
+            __COMPAT__ && __DEV__
+              ? defaultValue.call(createPropsDefaultThis(key), props)
+              : defaultValue(props)
           setCurrentInstance(null)
         }
       } else {