Refactor Fix and Edit API (#4198)

crates/ruff_diagnostics/src/diagnostic.rs

@@ -24,7 +24,7 @@ pub struct DiagnosticKind {
 pub struct Diagnostic {
     pub kind: DiagnosticKind,
     pub range: TextRange,
-    pub fix: Fix,
+    pub fix: Option<Fix>,
     pub parent: Option<TextSize>,
 }
 
@@ -33,7 +33,7 @@ impl Diagnostic {
         Self {
             kind: kind.into(),
             range,
-            fix: Fix::empty(),
+            fix: None,
             parent: None,
         }
     }
@@ -41,7 +41,7 @@ impl Diagnostic {
     /// Set the [`Fix`] used to fix the diagnostic.
     #[inline]
     pub fn set_fix<T: Into<Fix>>(&mut self, fix: T) {
-        self.fix = fix.into();
+        self.fix = Some(fix.into());
     }
 
     /// Consumes `self` and returns a new `Diagnostic` with the given `fix`.
@@ -57,7 +57,7 @@ impl Diagnostic {
     #[inline]
     pub fn try_set_fix<T: Into<Fix>>(&mut self, func: impl FnOnce() -> Result<T>) {
         match func() {
-            Ok(fix) => self.fix = fix.into(),
+            Ok(fix) => self.fix = Some(fix.into()),
             Err(err) => error!("Failed to create fix: {}", err),
         }
     }

crates/ruff_diagnostics/src/fix.rs

@@ -5,26 +5,23 @@ use serde::{Deserialize, Serialize};
 use crate::edit::Edit;
 
 /// A collection of [`Edit`] elements to be applied to a source file.
-#[derive(Default, Debug, PartialEq, Eq, Clone)]
+#[derive(Debug, PartialEq, Eq, Clone)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct Fix {
     edits: Vec<Edit>,
 }
 
 impl Fix {
-    /// Create a new [`Fix`] from a vector of [`Edit`] elements.
-    pub fn new(edits: Vec<Edit>) -> Self {
-        Self { edits }
+    /// Create a new [`Fix`] with an unspecified applicability from an [`Edit`] element.
+    pub fn unspecified(edit: Edit) -> Self {
+        Self { edits: vec![edit] }
     }
 
-    /// Create an empty [`Fix`].
-    pub const fn empty() -> Self {
-        Self { edits: Vec::new() }
-    }
-
-    /// Return `true` if the [`Fix`] contains no [`Edit`] elements.
-    pub fn is_empty(&self) -> bool {
-        self.edits.is_empty()
+    /// Create a new [`Fix`] with unspecified applicability from multiple [`Edit`] elements.
+    pub fn unspecified_edits(edit: Edit, rest: impl IntoIterator<Item = Edit>) -> Self {
+        Self {
+            edits: std::iter::once(edit).chain(rest.into_iter()).collect(),
+        }
     }
 
     /// Return the [`TextSize`] of the first [`Edit`] in the [`Fix`].
@@ -42,14 +39,6 @@ impl Fix {
     }
 }
 
-impl FromIterator<Edit> for Fix {
-    fn from_iter<T: IntoIterator<Item = Edit>>(iter: T) -> Self {
-        Self {
-            edits: Vec::from_iter(iter),
-        }
-    }
-}
-
 impl From<Edit> for Fix {
     fn from(edit: Edit) -> Self {
         Self { edits: vec![edit] }