src/test/ui/traits/self-without-lifetime-constraint.rs

   1 use std::error::Error;
   2 use std::fmt;
   3
   4 #[derive(Copy, Clone, Debug, PartialEq)]
   5 pub enum ValueRef<'a> {
   6     Null,
   7     Integer(i64),
   8     Real(f64),
   9     Text(&'a [u8]),
  10     Blob(&'a [u8]),
  11 }
  12
  13 impl<'a> ValueRef<'a> {
  14     pub fn as_str(&self) -> FromSqlResult<&'a str, &'a &'a str> {
  15         match *self {
  16             ValueRef::Text(t) => {
  17                 std::str::from_utf8(t).map_err(|_| FromSqlError::InvalidType).map(|x| (x, &x))
  18             }
  19             _ => Err(FromSqlError::InvalidType),
  20         }
  21     }
  22 }
  23
  24 #[derive(Debug)]
  25 #[non_exhaustive]
  26 pub enum FromSqlError {
  27     InvalidType
  28 }
  29
  30 impl fmt::Display for FromSqlError {
  31     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  32         write!(f, "InvalidType")
  33     }
  34 }
  35
  36 impl Error for FromSqlError {}
  37
  38 pub type FromSqlResult<T, K> = Result<(T, K), FromSqlError>;
  39
  40 pub trait FromSql: Sized {
  41     fn column_result(value: ValueRef<'_>) -> FromSqlResult<Self, &Self>;
  42 }
  43
  44 impl FromSql for &str {
  45     fn column_result(value: ValueRef<'_>) -> FromSqlResult<&str, &&str> {
  46     //~^ ERROR `impl` item signature doesn't match `trait` item signature
  47         value.as_str()
  48     }
  49 }
  50
  51 pub fn main() {
  52     println!("{}", "Hello World");
  53 }