src/librustc_error_codes/error_codes/E0019.md

   1 A function call isn't allowed in the const's initialization expression
   2 because the expression's value must be known at compile-time.
   3
   4 Erroneous code example:
   5
   6 ```compile_fail,E0019
   7 #![feature(box_syntax)]
   8
   9 fn main() {
  10     struct MyOwned;
  11
  12     static STATIC11: Box<MyOwned> = box MyOwned; // error!
  13 }
  14 ```
  15
  16 Remember: you can't use a function call inside a const's initialization
  17 expression! However, you can totally use it anywhere else:
  18
  19 ```
  20 enum Test {
  21     V1
  22 }
  23
  24 impl Test {
  25     fn func(&self) -> i32 {
  26         12
  27     }
  28 }
  29
  30 fn main() {
  31     const FOO: Test = Test::V1;
  32
  33     FOO.func(); // here is good
  34     let x = FOO.func(); // or even here!
  35 }
  36 ```