Method setOuterProperty

src/main/java/groovy/lang/MetaClassImpl.java:3100–3116

(Class<?> sender, final Object object, final String name, final Object newValue, final MissingPropertyException mpe)

    }

    private void setOuterProperty(Class<?> sender, final Object object, final String name, final Object newValue, final MissingPropertyException mpe) {
        if (sender == null) sender = theClass; // GROOVY-11745
        if (sender == theClass ? isGroovyObject() : GroovyObject.class.isAssignableFrom(sender)) {
            var outerClass = getNonClosureOuter(sender); // check outer class nesting of call site
            if (outerClass != null && (sender == theClass || sender.isAssignableFrom(theClass))) {
                MetaClass omc = registry.getMetaClass(outerClass);
                Object target = getOuterReference(sender, object);
                try {
                    omc.setProperty(outerClass, target, name, newValue, false, false);
                    return;
                } catch (MissingPropertyException e) {
                    mpe.addSuppressed(e);
                }
            }
        }
        throw mpe;
    }

    private MetaProperty getMetaProperty(final Class<?> clazz, final String name, final boolean useSuper, final boolean useStatic) {
        CachedClass cachedClass = (clazz == null || clazz == theClass) ? theCachedClass : ReflectionCache.getCachedClass(clazz);