Building queries like the following example which is for C++. Where the storage_class_specifier has zero or one (?) OR zero or more (*) matches throws a rust panic. Error: (rust-panic "Any { .. }") Note that one or more (+) works. I have only tested it for this case where there will be either one or none.
(
(declaration (storage_class_specifier)? @storage) @test
(.not-eq? @storage "")
)