Add more tests and fix lexer bug

src/parser/lexer.ts

@@ -644,10 +644,12 @@ export class StringLexer extends TrackedDiagnosticsMixin implements ILexer {
         const lineDelta = linesAdded - linesRemoved;
         /** The column directly after the inserted content */
         const endColumn =
-            linesAdded === 0
+            linesAdded !== 0
                 // If the edit doesn't include any newlines, add the byte delta to the starting column 
-                ? lastToken.range.end.col + byteDelta
-                : insert.length - insert.lastIndexOf('\n');
+                ? insert.length - insert.lastIndexOf('\n')
+            : linesRemoved !== 0
+                ? firstToken.range.start.col + insert.length
+                : lastToken.range.end.col + byteDelta;
 
         // Push onto the edit change so that tokens can update their position
         this.edits = this.edits.push({

tests/grammar/incremental.spec.ts

@@ -16,6 +16,7 @@ function testIncremental(title: string) {
             const p1 = new Parser();
             p1.setDiagnostics(d1.getReporter('mike'));
             p1.loadSource(original);
+            p1.parse();
             d1.clear();
             p1.editSource(part1.length, remove.length, insert);
 
@@ -149,9 +150,49 @@ export default () => describe('incremental', () => {
         }
     `;
 
-    testIncremental('shift diagnostic forwards')`
+    testIncremental('make change in the presence of parser diagnostic earlier in file')`
         on foo() {
-            let x = ${['1', '15']}; 10e;
+            x
+        }
+
+        on bar() {
+            let x = ${['1', '15']};
+        }
+    `;
+
+    testIncremental('make change in the presence of parser diagnostic later in file')`
+        on foo() {
+            let x = ${['1', '15']};
+        }
+
+        on bar() {
+            x
+        }
+    `;
+
+    testIncremental('make change which would shift lexer diagnostic to another column')`
+        on foo() {
+            let x = ${['1', '15']}; @
+        }
+    `;
+
+    testIncremental('make change which would shift lexer diagnostic to another line')`
+        on foo() {
+            let x = ${['1', `"
+            "`]}; @
+        }
+    `;
+
+    testIncremental('make change which would shift parser diagnostic to another column')`
+        on foo() {
+            let x = ${['1', '15']}; x123
+        }
+    `;
+
+    testIncremental('make change which would shift parser diagnostic to another line')`
+        on foo() {
+            let x = ${['1', `
+                1`]}; x123
         }
     `;