error nodes: removed traversal into AnyNodes, added `visit_error_ch…

…ild` visitor function in exchange

crates/core/src/ast/traversal/visitor.rs

@@ -1,5 +1,6 @@
 use crate::tokens::*;
 use crate::ast::*;
+use crate::AnyNode;
 use crate::ErrorNode;
 use super::policies::*;
 use super::contexts::*;
@@ -280,8 +281,12 @@ pub trait SyntaxNodeVisitor {
     /// Called when visiting an unnamed node (i.e. keyword or punctuation).
     fn visit_unnamed(&mut self, n: &UnnamedNode, ctx: &TraversalContextStack) {}
 
+
     /// Called when visiting a node representing a syntax error.
     fn visit_error(&mut self, n: &ErrorNode, ctx: &TraversalContextStack) -> ErrorTraversalPolicy { TraversalPolicy::default_to(self.traversal_policy_default()) }
     /// Called after visiting a node representing a syntax error and possibly also children nodes specified in traversal policy.
     fn exit_error(&mut self, n: &ErrorNode, ctx: &TraversalContextStack) {}
+
+    /// Called when visiting a child node of an error node. The actual kind of node is not resolved automatically and thus not traversed into.
+    fn visit_error_child(&mut self, n: &AnyNode, ctx: &TraversalContextStack) {}
 }

crates/core/src/ast/traversal/visitor_chain.rs

@@ -1,5 +1,5 @@
 use std::{cell::{RefCell, RefMut}, rc::Rc};
-use crate::{ast::*, ErrorNode};
+use crate::{ast::*, AnyNode, ErrorNode};
 use crate::tokens::*;
 
 
@@ -595,4 +595,9 @@ impl<'a> SyntaxNodeVisitor for SyntaxNodeVisitorChain<'a> {
     fn exit_error(&mut self, n: &ErrorNode, ctx: &TraversalContextStack) {
         self.chain_exit(move |link| link.exit_error(n, ctx))
     }
+
+    #[inline]
+    fn visit_error_child(&mut self, n: &AnyNode, ctx: &TraversalContextStack) {
+        self.chain_visit(move |link| link.visit_error_child(n, ctx))
+    }
 }

crates/core/src/syntax_error.rs

@@ -29,16 +29,15 @@ impl std::fmt::Debug for ErrorNode<'_> {
 impl<'script> SyntaxNodeTraversal for ErrorNode<'script> {
     fn accept<V: SyntaxNodeVisitor>(&self, visitor: &mut V, ctx: &mut TraversalContextStack) {
         let tp = visitor.visit_error(self, ctx);
-        ctx.push(TraversalContext::Error);
         if tp.traverse {
-            for res in self.children_detailed() {
-                match res {
-                    Ok((n, _)) => n.accept(visitor, ctx),
-                    Err(e) => e.accept(visitor, ctx)
-                }
+            ctx.push(TraversalContext::Error);
+
+            for n in self.children().can_be_error(true) {
+                visitor.visit_error_child(&n, ctx);
             }
+
+            ctx.pop();
         }
-        ctx.pop();
         visitor.exit_error(self, ctx);
     }
 }

crates/core/src/syntax_node.rs

@@ -284,7 +284,8 @@ pub struct SyntaxNodeChildren<'script> {
     cursor: ts::TreeCursor<'script>,
     any_children_left: bool,
 
-    must_be_named: bool
+    must_be_named: bool,
+    can_be_error: bool
 }
 
 impl<'script> SyntaxNodeChildren<'script> {
@@ -296,14 +297,20 @@ impl<'script> SyntaxNodeChildren<'script> {
             cursor,
             any_children_left,
 
-            must_be_named: false
+            must_be_named: false,
+            can_be_error: false
         }
     }
 
     pub fn must_be_named(mut self, b: bool) -> Self {
         self.must_be_named = b;
         self
     }
+
+    pub fn can_be_error(mut self, b: bool) -> Self {
+        self.can_be_error = b;
+        self
+    }
 }
 
 impl<'script> Iterator for SyntaxNodeChildren<'script> {
@@ -313,7 +320,7 @@ impl<'script> Iterator for SyntaxNodeChildren<'script> {
         if self.any_children_left {
             let mut n = self.cursor.node();
             while n.is_extra()
-            || n.is_error()
+            || (!self.can_be_error && n.is_error())
             || (self.must_be_named && !n.is_named()) {
                 if self.cursor.goto_next_sibling() {
                     n = self.cursor.node();