src/vendor/serde_derive/src/try.rs

   1 use proc_macro2::{Punct, Spacing, TokenStream};
   2
   3 // None of our generated code requires the `From::from` error conversion
   4 // performed by the standard library's `try!` macro. With this simplified macro
   5 // we see a significant improvement in type checking and borrow checking time of
   6 // the generated code and a slight improvement in binary size.
   7 pub fn replacement() -> TokenStream {
   8     // Cannot pass `$expr` to `quote!` prior to Rust 1.17.0 so interpolate it.
   9     let dollar = Punct::new('$', Spacing::Alone);
  10
  11     quote! {
  12         #[allow(unused_macros)]
  13         macro_rules! try {
  14             (#dollar __expr:expr) => {
  15                 match #dollar __expr {
  16                     _serde::export::Ok(__val) => __val,
  17                     _serde::export::Err(__err) => {
  18                         return _serde::export::Err(__err);
  19                     }
  20                 }
  21             }
  22         }
  23     }
  24 }