src/test/ui/or-patterns/or-patterns-syntactic-fail.rs

   1 // Test some cases where or-patterns may ostensibly be allowed but are in fact not.
   2 // This is not a semantic test. We only test parsing.
   3
   4 fn main() {}
   5
   6 enum E { A, B }
   7 use E::*;
   8
   9 fn no_top_level_or_patterns() {
  10     // We do *not* allow or-patterns at the top level of lambdas...
  11     let _ = |A | B: E| (); //~ ERROR no implementation for `E | ()`
  12     //           -------- This looks like an or-pattern but is in fact `|A| (B: E | ())`.
  13
  14     // ...and for now neither do we allow or-patterns at the top level of functions.
  15     fn fun1(A | B: E) {}
  16     //~^ ERROR top-level or-patterns are not allowed
  17
  18     fn fun2(| A | B: E) {}
  19     //~^ ERROR top-level or-patterns are not allowed
  20
  21     // We don't allow top-level or-patterns before type annotation in let-statements because we
  22     // want to reserve this syntactic space for possible future type ascription.
  23     let A | B: E = A;
  24     //~^ ERROR top-level or-patterns are not allowed
  25
  26     let | A | B: E = A;
  27     //~^ ERROR top-level or-patterns are not allowed
  28
  29     let (A | B): E = A; // ok -- wrapped in parens
  30 }