UseImportsTraverser optimization opportunity

[staabm]

looking at a codeigniter profile, I can see UseImportsTraverser to use a considerable amount of time

In the UseImportsTraverser I can see it is using SimpleCallableNodeTraverser to deep travers statements.

looking at the php-src docs I noted..

The use keyword must be declared in the outermost scope of a file (the global scope) or inside namespace declarations. This is because the importing is done at compile time and not runtime, so it cannot be block scoped. The following example will show an illegal use of the use keyword

doesn't this mean, that we can stop traversing the statements in UseImportsTraverser as soon as we hit a function or class?
(or maybe at leaset it means we need only a linear scan of the top level and no deep traversal).

leaving it here for discussion