vendor/rustc-rayon/src/compile_fail/must_use.rs

   1 // Check that we are flagged for ignoring `must_use` parallel adaptors.
   2 // (unfortunately there's no error code for `unused_must_use`)
   3
   4 macro_rules! must_use {
   5     ($( $name:ident #[$expr:meta] )*) => {$(
   6         /// First sanity check that the expression is OK.
   7         ///
   8         /// ```
   9         /// #![deny(unused_must_use)]
  10         ///
  11         /// use rayon::prelude::*;
  12         ///
  13         /// let v: Vec<_> = (0..100).map(Some).collect();
  14         /// let _ =
  15         #[$expr]
  16         /// ```
  17         ///
  18         /// Now trigger the `must_use`.
  19         ///
  20         /// ```compile_fail
  21         /// #![deny(unused_must_use)]
  22         ///
  23         /// use rayon::prelude::*;
  24         ///
  25         /// let v: Vec<_> = (0..100).map(Some).collect();
  26         #[$expr]
  27         /// ```
  28         mod $name {}
  29     )*}
  30 }
  31
  32 must_use! {
  33     chain               /** v.par_iter().chain(&v); */
  34     chunks              /** v.par_iter().chunks(2); */
  35     cloned              /** v.par_iter().cloned(); */
  36     copied              /** v.par_iter().copied(); */
  37     enumerate           /** v.par_iter().enumerate(); */
  38     filter              /** v.par_iter().filter(|_| true); */
  39     filter_map          /** v.par_iter().filter_map(|x| *x); */
  40     flat_map            /** v.par_iter().flat_map(|x| *x); */
  41     flatten             /** v.par_iter().flatten(); */
  42     fold                /** v.par_iter().fold(|| 0, |x, _| x); */
  43     fold_with           /** v.par_iter().fold_with(0, |x, _| x); */
  44     try_fold            /** v.par_iter().try_fold(|| 0, |x, _| Some(x)); */
  45     try_fold_with       /** v.par_iter().try_fold_with(0, |x, _| Some(x)); */
  46     inspect             /** v.par_iter().inspect(|_| {}); */
  47     interleave          /** v.par_iter().interleave(&v); */
  48     interleave_shortest /** v.par_iter().interleave_shortest(&v); */
  49     intersperse         /** v.par_iter().intersperse(&None); */
  50     map                 /** v.par_iter().map(|x| x); */
  51     map_with            /** v.par_iter().map_with(0, |_, x| x); */
  52     map_init            /** v.par_iter().map_init(|| 0, |_, x| x); */
  53     panic_fuse          /** v.par_iter().panic_fuse(); */
  54     rev                 /** v.par_iter().rev(); */
  55     skip                /** v.par_iter().skip(1); */
  56     take                /** v.par_iter().take(1); */
  57     update              /** v.par_iter().update(|_| {}); */
  58     while_some          /** v.par_iter().cloned().while_some(); */
  59     with_max_len        /** v.par_iter().with_max_len(1); */
  60     with_min_len        /** v.par_iter().with_min_len(1); */
  61     zip                 /** v.par_iter().zip(&v); */
  62     zip_eq              /** v.par_iter().zip_eq(&v); */
  63 }