Allow diagnostics to generate multi-edit fixes (#3709)

crates/ruff_diagnostics/src/fix.rs

@@ -0,0 +1,58 @@
+use rustpython_parser::ast::Location;
+#[cfg(feature = "serde")]
+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)]
+#[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 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()
+    }
+
+    /// Return the [`Location`] of the first [`Edit`] in the [`Fix`].
+    pub fn location(&self) -> Option<Location> {
+        self.edits.iter().map(|edit| edit.location).min()
+    }
+
+    /// Return the [`Location`] of the last [`Edit`] in the [`Fix`].
+    pub fn end_location(&self) -> Option<Location> {
+        self.edits.iter().map(|edit| edit.end_location).max()
+    }
+
+    /// Return a slice of the [`Edit`] elements in the [`Fix`].
+    pub fn edits(&self) -> &[Edit] {
+        &self.edits
+    }
+}
+
+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] }
+    }
+}