Make sure document diagnostics are sorted

helix-core/src/diagnostic.rs

@@ -10,7 +10,7 @@ pub enum Severity {
 }
 
 /// A range of `char`s within the text.
-#[derive(Debug)]
+#[derive(Debug, Clone, Copy, PartialOrd, Ord, PartialEq, Eq)]
 pub struct Range {
     pub start: usize,
     pub end: usize,

helix-view/src/document.rs

@@ -918,6 +918,9 @@ impl Document {
 
     pub fn set_diagnostics(&mut self, diagnostics: Vec<Diagnostic>) {
         self.diagnostics = diagnostics;
+        // sort by range
+        self.diagnostics
+            .sort_unstable_by_key(|diagnostic| diagnostic.range);
     }
 }