Function collect_error_nodes 

pub fn collect_error_nodes(tree: &Tree) -> Vec<SyntaxDiagnostic>

Walks a tree-sitter Tree and collects a SyntaxDiagnostic for every ERROR node and every “missing” node it contains, in document order.

This is purely a syntactic operation: it does not attempt to convert anything to pactole-core domain models.

This variant has no access to the original source text, so ERROR diagnostics cannot quote the unexpected text; prefer collect_error_nodes_with_source when the source text is available (as parse_document does internally).