1 files changed, 67 insertions, 17 deletions

diff --git a/crates/ra_syntax/src/parsing/reparsing.rs b/crates/ra_syntax/src/parsing/reparsing.rs
index a86da0675..aad70d015 100644
--- a/crates/ra_syntax/src/parsing/reparsing.rs
+++ b/crates/ra_syntax/src/parsing/reparsing.rs
@@ -27,8 +27,8 @@ pub(crate) fn incremental_reparse(
     edit: &AtomTextEdit,
     errors: Vec<SyntaxError>,
 ) -> Option<(GreenNode, Vec<SyntaxError>, TextRange)> {
-    if let Some((green, old_range)) = reparse_token(node, &edit) {
-        return Some((green, merge_errors(errors, Vec::new(), old_range, edit), old_range));
+    if let Some((green, new_errors, old_range)) = reparse_token(node, &edit) {
+        return Some((green, merge_errors(errors, new_errors, old_range, edit), old_range));
     }
 
     if let Some((green, new_errors, old_range)) = reparse_block(node, &edit) {
@@ -40,7 +40,7 @@ pub(crate) fn incremental_reparse(
 fn reparse_token<'node>(
     root: &'node SyntaxNode,
     edit: &AtomTextEdit,
-) -> Option<(GreenNode, TextRange)> {
+) -> Option<(GreenNode, Vec<SyntaxError>, TextRange)> {
     let prev_token = algo::find_covering_element(root, edit.delete).as_token()?.clone();
     let prev_token_kind = prev_token.kind();
     match prev_token_kind {
@@ -54,7 +54,7 @@ fn reparse_token<'node>(
             }
 
             let mut new_text = get_text_after_edit(prev_token.clone().into(), &edit);
-            let (new_token_kind, _error) = lex_single_syntax_kind(&new_text)?;
+            let (new_token_kind, new_err) = lex_single_syntax_kind(&new_text)?;
 
             if new_token_kind != prev_token_kind
                 || (new_token_kind == IDENT && is_contextual_kw(&new_text))
@@ -76,7 +76,11 @@ fn reparse_token<'node>(
 
             let new_token =
                 GreenToken::new(rowan::SyntaxKind(prev_token_kind.into()), new_text.into());
-            Some((prev_token.replace_with(new_token), prev_token.text_range()))
+            Some((
+                prev_token.replace_with(new_token),
+                new_err.into_iter().collect(),
+                prev_token.text_range(),
+            ))
         }
         _ => None,
     }
@@ -87,7 +91,7 @@ fn reparse_block<'node>(
     edit: &AtomTextEdit,
 ) -> Option<(GreenNode, Vec<SyntaxError>, TextRange)> {
     let (node, reparser) = find_reparsable_node(root, edit.delete)?;
-    let text = get_text_after_edit(node.clone().into(), &edit);
+    let text = get_text_after_edit(node.clone().into(), edit);
 
     let (tokens, new_lexer_errors) = tokenize(&text);
     if !is_balanced(&tokens) {
@@ -162,20 +166,27 @@ fn is_balanced(tokens: &[Token]) -> bool {
 fn merge_errors(
     old_errors: Vec<SyntaxError>,
     new_errors: Vec<SyntaxError>,
-    old_range: TextRange,
+    range_before_reparse: TextRange,
     edit: &AtomTextEdit,
 ) -> Vec<SyntaxError> {
     let mut res = Vec::new();
-    for e in old_errors {
-        if e.offset() <= old_range.start() {
-            res.push(e)
-        } else if e.offset() >= old_range.end() {
-            res.push(e.add_offset(TextUnit::of_str(&edit.insert), edit.delete.len()));
+
+    for old_err in old_errors {
+        let old_err_range = old_err.range();
+        // FIXME: make sure that .start() was here previously by a mistake
+        if old_err_range.end() <= range_before_reparse.start() {
+            res.push(old_err);
+        } else if old_err_range.start() >= range_before_reparse.end() {
+            let inserted_len = TextUnit::of_str(&edit.insert);
+            res.push(old_err.with_range((old_err_range + inserted_len) - edit.delete.len()));
+            // Note: extra parens are intentional to prevent uint underflow, HWAB (here was a bug)
         }
     }
-    for e in new_errors {
-        res.push(e.add_offset(old_range.start(), 0.into()));
-    }
+    res.extend(new_errors.into_iter().map(|new_err| {
+        // fighting borrow checker with a variable ;)
+        let offseted_range = new_err.range() + range_before_reparse.start();
+        new_err.with_range(offseted_range)
+    }));
     res
 }
 
@@ -193,9 +204,9 @@ mod tests {
 
         let fully_reparsed = SourceFile::parse(&after);
         let incrementally_reparsed: Parse<SourceFile> = {
-            let f = SourceFile::parse(&before);
+            let before = SourceFile::parse(&before);
             let (green, new_errors, range) =
-                incremental_reparse(f.tree().syntax(), &edit, f.errors.to_vec()).unwrap();
+                incremental_reparse(before.tree().syntax(), &edit, before.errors.to_vec()).unwrap();
             assert_eq!(range.len(), reparsed_len.into(), "reparsed fragment has wrong length");
             Parse::new(green, new_errors)
         };
@@ -204,6 +215,7 @@ mod tests {
             &format!("{:#?}", fully_reparsed.tree().syntax()),
             &format!("{:#?}", incrementally_reparsed.tree().syntax()),
         );
+        assert_eq!(fully_reparsed.errors(), incrementally_reparsed.errors());
     }
 
     #[test] // FIXME: some test here actually test token reparsing
@@ -402,4 +414,42 @@ enum Foo {
             4,
         );
     }
+
+    #[test]
+    fn reparse_str_token_with_error_unchanged() {
+        do_check(r#""<|>Unclosed<|> string literal"#, "Still unclosed", 24);
+    }
+
+    #[test]
+    fn reparse_str_token_with_error_fixed() {
+        do_check(r#""unterinated<|><|>"#, "\"", 12);
+    }
+
+    #[test]
+    fn reparse_block_with_error_in_middle_unchanged() {
+        do_check(
+            r#"fn main() {
+                if {}
+                32 + 4<|><|>
+                return
+                if {}
+            }"#,
+            "23",
+            105,
+        )
+    }
+
+    #[test]
+    fn reparse_block_with_error_in_middle_fixed() {
+        do_check(
+            r#"fn main() {
+                if {}
+                32 + 4<|><|>
+                return
+                if {}
+            }"#,
+            ";",
+            105,
+        )
+    }
 }