message: Finish removing PreviewNotFound
diff: @@ -40,10 +40,6 @@ pub enum Message {
  file: String,
  message: String,
  },
  - PreviewNotFound {
  - file: String,
  - edition: String,
  - },
  EditionAlreadyEnabled {
  file: String,
  edition: String,
  @@ -81,7 +77,6 @@ impl Message {
  pub struct DiagnosticPrinter<'a> {
  config: &'a Config,
  - preview_not_found: HashSet<String>,
  edition_already_enabled: HashSet<String>,
  idiom_mismatch: HashSet<String>,
  }
  @@ -90,7 +85,6 @@ impl<'a> DiagnosticPrinter<'a> {
  pub fn new(config: &'a Config) -> DiagnosticPrinter<'a> {
  DiagnosticPrinter {
  config,
  - preview_not_found: HashSet::new(),
  edition_already_enabled: HashSet::new(),
  idiom_mismatch: HashSet::new(),
  }
  @@ -140,21 +134,6 @@ impl<'a> DiagnosticPrinter<'a> {
  write!(self.config.shell().err(), "{}", PLEASE_REPORT_THIS_BUG)?;
  Ok(())
  }
  - Message::PreviewNotFound { file, edition } => {
  - // By default we're fixing a lot of things concurrently, don't
  - // warn about the same file multiple times.
  - if !self.preview_not_found.insert(file.clone()) {
  - return Ok(())
  - }
  - self.config.shell().warn(&format!(
  - "failed to find `#![feature(rust_{}_preview)]` in `{}`\n\
  - this may cause `cargo fix` to not be able to fix all\n\
  - issues in preparation for the {0} edition",
  - edition,
  - file,
  - ))?;
  - Ok(())
  - }
  Message::EditionAlreadyEnabled { file, edition } => {
  // Like above, only warn once per file
  if !self.edition_already_enabled.insert(file.clone()) {
  