Struct syntex_syntax::ext::mtwt::SCTable

pub struct SCTable {
    // some fields omitted
}

The SCTable contains a table of SyntaxContext_'s. It represents a flattened tree structure, to avoid having managed pointers everywhere (that caused an ICE). the mark_memo and rename_memo fields are side-tables that ensure that adding the same mark to the same context gives you back the same context as before. This shouldn't change the semantics--everything here is immutable--but it should cut down on memory use a lot; applying a mark to a tree containing 50 identifiers would otherwise generate 50 new contexts