Macro rustc_middle::ty::query::opt_remap_env_constness

macro_rules! opt_remap_env_constness {
    ([][$name:ident]) => { ... };
    ([(remap_env_constness) $($rest:tt)*][$name:ident]) => { ... };
    ([$other:tt $($modifiers:tt)*][$name:ident]) => { ... };
}