Export 'Error::chain()'. Impl 'Error: From<&str>'.

src/error.rs

@@ -23,15 +23,17 @@ pub type Result<T> = std::result::Result<T, Error>;
 ///
 /// Broadly, there are two ways to construct an `Error`:
 ///
-/// * Via an error message, since `Error` impls `From<String>`:
+/// * With an error message, as `Error` impls `From<String>` and `From<&str>`:
 ///
 /// ```
 /// use figment::Error;
 ///
-/// Error::from("whoops, something went wrong!".to_string());
+/// Error::from(format!("{} is invalid", 1));
+///
+/// Error::from("whoops, something went wrong!");
 /// ```
 ///
-/// * Via a [`Kind`], since `Error` impls `From<Kind>`:
+/// * With a [`Kind`], as `Error` impls `From<Kind>`:
 ///
 /// ```
 /// use figment::{error::{Error, Kind}, value::Value};
@@ -144,11 +146,6 @@ impl Error {
  self
  }
 
- pub(crate) fn chain(self, mut error: Error) -> Self {
- error.prev = Some(Box::new(self));
- error
- }
-
  pub(crate) fn retagged(mut self, tag: Tag) -> Self {
  if self.tag.is_default() {
  self.tag = tag;
@@ -201,6 +198,39 @@ impl Error {
  self
  }
 
+ /// Prepends `self` to `error` and returns `error`.
+ ///
+ /// ```rust
+ /// use figment::error::Error;
+ ///
+ /// let e1 = Error::from("1");
+ /// let e2 = Error::from("2");
+ /// let e3 = Error::from("3");
+ ///
+ /// let error = e1.chain(e2).chain(e3);
+ /// assert_eq!(error.count(), 3);
+ ///
+ /// let unchained = error.into_iter()
+ /// .map(|e| e.to_string())
+ /// .collect::<Vec<_>>();
+ /// assert_eq!(unchained, vec!["3", "2", "1"]);
+ ///
+ /// let e1 = Error::from("1");
+ /// let e2 = Error::from("2");
+ /// let e3 = Error::from("3");
+ /// let error = e3.chain(e2).chain(e1);
+ /// assert_eq!(error.count(), 3);
+ ///
+ /// let unchained = error.into_iter()
+ /// .map(|e| e.to_string())
+ /// .collect::<Vec<_>>();
+ /// assert_eq!(unchained, vec!["1", "2", "3"]);
+ /// ```
+ pub fn chain(self, mut error: Error) -> Self {
+ error.prev = Some(Box::new(self));
+ error
+ }
+
  /// Returns the number of errors represented by `self`.
  ///
  /// # Example
@@ -386,6 +416,12 @@ impl From<Kind> for Error {
  }
 }
 
+impl From<&str> for Error {
+ fn from(string: &str) -> Error {
+ Kind::Message(string.into()).into()
+ }
+}
+
 impl From<String> for Error {
  fn from(string: String) -> Error {
  Kind::Message(string).into()