Provide better stack trace for overlapping edits

Overlapping indels are a bug. Checking this *always* is tricky (needs
a sorted data structure to not suffer O(N^2) perf). But
opportunistically checking small indels should give provide 80% of the
benefits.

Author: matklad

crates/text_edit/src/lib.rs

@@ -159,13 +159,13 @@ impl<'a> IntoIterator for &'a TextEdit {
 
 impl TextEditBuilder {
     pub fn replace(&mut self, range: TextRange, replace_with: String) {
-        self.indels.push(Indel::replace(range, replace_with))
+        self.indel(Indel::replace(range, replace_with))
     }
     pub fn delete(&mut self, range: TextRange) {
-        self.indels.push(Indel::delete(range))
+        self.indel(Indel::delete(range))
     }
     pub fn insert(&mut self, offset: TextSize, text: String) {
-        self.indels.push(Indel::insert(offset, text))
+        self.indel(Indel::insert(offset, text))
     }
     pub fn finish(self) -> TextEdit {
         let mut indels = self.indels;
@@ -175,6 +175,12 @@ impl TextEditBuilder {
     pub fn invalidates_offset(&self, offset: TextSize) -> bool {
         self.indels.iter().any(|indel| indel.delete.contains_inclusive(offset))
     }
+    fn indel(&mut self, indel: Indel) {
+        self.indels.push(indel);
+        if self.indels.len() <= 16 {
+            check_disjoint(&mut self.indels);
+        }
+    }
 }
 
 fn check_disjoint(indels: &mut [impl std::borrow::Borrow<Indel>]) -> bool {