Function ty_query 

pub(crate) fn ty_query<'db>(
    db: &'db dyn HirDatabase,
    def: TyDefId,
) -> EarlyBinder<'db, Ty<'db>>

Build the declared type of an item. This depends on the namespace; e.g. for struct Foo(usize), we have two types: The type of the struct itself, and the constructor function (usize) -> Foo which lives in the values namespace.