src/test/ui/pattern/rest-pat-semantic-disallowed.rs

   1 // Here we test that rest patterns, i.e. `..`, are not allowed
   2 // outside of slice (+ ident patterns witin those), tuple,
   3 // and tuple struct patterns and that duplicates are caught in these contexts.
   4
   5 #![feature(slice_patterns, box_patterns)]
   6
   7 fn main() {}
   8
   9 macro_rules! mk_pat {
  10     () => { .. } //~ ERROR `..` patterns are not allowed here
  11 }
  12
  13 fn rest_patterns() {
  14     let mk_pat!();
  15
  16     // Top level:
  17     fn foo(..: u8) {} //~ ERROR `..` patterns are not allowed here
  18     let ..;  //~ ERROR `..` patterns are not allowed here
  19
  20     // Box patterns:
  21     let box ..;  //~ ERROR `..` patterns are not allowed here
  22
  23     // In or-patterns:
  24     match 1 {
  25         1 | .. => {} //~ ERROR `..` patterns are not allowed here
  26     }
  27
  28     // Ref patterns:
  29     let &..; //~ ERROR `..` patterns are not allowed here
  30     let &mut ..; //~ ERROR `..` patterns are not allowed here
  31
  32     // Ident patterns:
  33     let x @ ..; //~ ERROR `..` patterns are not allowed here
  34     //~^ ERROR type annotations needed
  35     let ref x @ ..; //~ ERROR `..` patterns are not allowed here
  36     let ref mut x @ ..; //~ ERROR `..` patterns are not allowed here
  37
  38     // Tuple:
  39     let (..): (u8,); // OK.
  40     let (..,): (u8,); // OK.
  41     let (
  42         ..,
  43         .., //~ ERROR `..` can only be used once per tuple pattern
  44         .. //~ ERROR `..` can only be used once per tuple pattern
  45     ): (u8, u8, u8);
  46     let (
  47         ..,
  48         x,
  49         .. //~ ERROR `..` can only be used once per tuple pattern
  50     ): (u8, u8, u8);
  51
  52     struct A(u8, u8, u8);
  53
  54     // Tuple struct (same idea as for tuple patterns):
  55     let A(..); // OK.
  56     let A(..,); // OK.
  57     let A(
  58         ..,
  59         .., //~ ERROR `..` can only be used once per tuple struct pattern
  60         .. //~ ERROR `..` can only be used once per tuple struct pattern
  61     );
  62     let A(
  63         ..,
  64         x,
  65         .. //~ ERROR `..` can only be used once per tuple struct pattern
  66     );
  67
  68     // Array/Slice:
  69     let [..]: &[u8]; // OK.
  70     let [..,]: &[u8]; // OK.
  71     let [
  72         ..,
  73         .., //~ ERROR `..` can only be used once per slice pattern
  74         .. //~ ERROR `..` can only be used once per slice pattern
  75     ]: &[u8];
  76     let [
  77         ..,
  78         ref x @ .., //~ ERROR `..` can only be used once per slice pattern
  79         ref mut y @ .., //~ ERROR `..` can only be used once per slice pattern
  80         (ref z @ ..), //~ ERROR `..` patterns are not allowed here
  81         .. //~ ERROR `..` can only be used once per slice pattern
  82     ]: &[u8];
  83 }