parser: deal with 
 and missing content.

Author: kivikakk

src/parser/mod.rs

@@ -3067,15 +3067,22 @@ where
             return;
         }
 
-        text.drain(..end);
-
         // These are sound only because the exact text that we've matched and
         // the count thereof (i.e. "end") will precisely map to characters in
         // the source document.
-        sourcepos.start.column += end;
-        let reference = spx.consume(end) + 1;
-        assert_eq!(reference, sourcepos.start.column);
-        parent.data.borrow_mut().sourcepos.start.column += end;
+        text.drain(..end);
+
+        let adjust = spx.consume(end) + 1;
+        // Do we need to account separately for the parent? I _think_ it always
+        // has the same start col to begin with as `sourcepos` itself.
+        assert_eq!(
+            sourcepos.start.column,
+            parent.data.borrow().sourcepos.start.column
+        );
+
+        // HACK: See tests::fuzz::echaw9. The paragraph doesn't exist in the source!
+        sourcepos.start.column = usize::min(sourcepos.end.column, adjust);
+        parent.data.borrow_mut().sourcepos.start.column = sourcepos.start.column;
 
         grandparent.data.borrow_mut().value =
             NodeValue::TaskItem(if symbol == ' ' { None } else { Some(symbol) });

src/tests/fuzz.rs

@@ -346,17 +346,12 @@ fn echaw8() {
 fn echaw9() {
     // fuzz/artifacts/all_options/minimized-from-8a07a44ba1f971ec39d0c14d377c78c2535c6fd5
     assert_ast_match!(
-        [extension.autolink, extension.tasklist],
+        [extension.tasklist],
         "-\t[ ]
",
-        (document (1:1-1:15) [
-            (list (1:1-1:15) [
-                (taskitem (1:1-1:15) [
-                    (paragraph (1:7-1:17) [
-                        (text (1:7-1:13) "𝔛-<")
-                        (link (1:14-1:17) "mailto:A@.N" [
-                            (text (1:14-1:17) "A@.N")
-                        ])
-                    ])
+        (document (1:1-1:14) [
+            (list (1:1-1:14) [
+                (taskitem (1:1-1:14) [
+                    (paragraph (1:14-1:14)) // Unsatisfying. See parser::process_tasklist.
                 ])
             ])
         ]),