{"ast_node_type":"other","tokens":[{"end":76,"kind":"keyword","start":0,"text":"//"}]}
                // could be a problem for `ImmTy` (see layout_sanity_check):
                // There are 3 cases where downcasts can turn a Scalar/ScalarPair into a different ABI which
                // - variant.size == Size::ZERO: works fine because `ImmTy::offset` has a special case for