{"ast_node_type":"other","tokens":[{"end":118,"kind":"keyword","start":0,"text":"//"}]}
                    // we instantiate the defaults with the partially built args when we build the args. Instantiating
                    // This causes ICEs (#86580) when building the args for Foo in `fn foo() -> Foo { .. }` as
                    // the `N#0` on the unevaluated const indexes into the empty args we're in the process of building.