rust: Fix deprecation warnings

src/data.rs

@@ -737,8 +737,7 @@ fn create_button<H: logging::Handler>(
 #[cfg(test)]
 mod tests {
     use super::*;
-    
+
-    use std::error::Error as ErrorTrait;
     use ::logging::ProblemPanic;
 
     const THIS_FILE: &str = file!();
@@ -786,7 +785,8 @@ mod tests {
             Err(e) => {
                 let mut handled = false;
                 if let Error::Yaml(ye) = &e {
-                    handled = ye.description() == "missing field `views`";
+                    handled = ye.to_string()
+                        .starts_with("missing field `views`");
                 };
                 if !handled {
                     println!("Unexpected error {:?}", e);
@@ -804,7 +804,7 @@ mod tests {
             Err(e) => {
                 let mut handled = false;
                 if let Error::Yaml(ye) = &e {
-                    handled = ye.description()
+                    handled = ye.to_string()
                         .starts_with("unknown field `bad_field`");
                 };
                 if !handled {

src/locale_config.rs

@@ -31,22 +31,16 @@ pub enum Error {
 
 impl ::std::fmt::Display for Error {
     fn fmt(&self, out: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
-        use ::std::error::Error;
+        out.write_str(match self {
-        out.write_str(self.description())
-    }
-}
-
-impl ::std::error::Error for Error {
-    fn description(&self) -> &str {
-        match self {
             &Error::NotWellFormed => "Language tag is not well-formed.",
             // this is exception: here we do want exhaustive match so we don't publish version with
             // missing descriptions by mistake.
             &Error::__NonExhaustive => panic!("Placeholder error must not be instantiated!"),
-        }
+        })
     }
 }
 
+
 /// Convenience Result alias.
 type Result<T> = ::std::result::Result<T, Error>;