syntax_data: {"ast_node_type":"other","tokens":[{"end":93,"kind":"keyword","start":0,"text":"Tree::def(Def::NoSafetyInvariants).then(Tree::def(Def::HasSafetyInvariants));"}]}
source_snippet:                 Tree::def(Def::NoSafetyInvariants).then(Tree::def(Def::HasSafetyInvariants));
context_before:             let layout: Tree<Def, !, !> =
context_after:             assert_eq!(