diff options
Diffstat (limited to 'src/util.rs')
| -rw-r--r-- | src/util.rs | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/src/util.rs b/src/util.rs index 5c9ffb8..d96c4f4 100644 --- a/src/util.rs +++ b/src/util.rs @@ -1,13 +1,38 @@ macro_rules! trait_alias { ( $(#[$attr: meta])* - $visibility: vis $name: ident$(<$($type_param: ident),*>)?$(: $first_bound: tt $(+ $bound: tt)*)?; + $visibility: vis $name: ident$(<$($type_param: ident),*>)? + $(: $first_bound: tt $(+ $bound: tt)*)?; ) => { $(#[$attr])* $visibility trait $name $(<$($type_param),*>)? $(: $first_bound $(+ $bound)*)? {} - impl<T: $($first_bound $(+ $bound)*)?, $($($type_param),*)?> $name$(<$($type_param),*>)? for T {} + impl< + T: $($first_bound $(+ $bound)*)?, + $($($type_param),*)? + > $name$(<$($type_param),*>)? for T {} }; + + // Rule where the trait bounds will only be applied if the specified feature is enabled + ( + bounds_when_feature = $bounds_feature: literal, + $(#[$attr: meta])* + $visibility: vis $name: ident$(<$($type_param: ident),*>)? + $(: $first_bound: tt $(+ $bound: tt)*)?; + ) => { + #[cfg(feature = $bounds_feature)] + trait_alias! { + $(#[$attr])* + $visibility $name$(<$($type_param),*>)? + $(: $first_bound $(+ $bound)*)?; + } + + #[cfg(not(feature = $bounds_feature))] + trait_alias! { + $(#[$attr])* + $visibility $name$(<$($type_param),*>)?; + } + } } macro_rules! feature_alternate { |