message: Make it clearer on assertion-failure what value is expected.
diff: @@ -60,23 +60,25 @@ const Symbol* DescendThroughSingletons(const Symbol& symbol);
  // Returns same node reference, so that anywhere that expects a SyntaxTreeNode
  // can be passed CheckNodeEnum(node, node_enum).
  template <typename E>
  -const SyntaxTreeNode& CheckNodeEnum(const SyntaxTreeNode& node, E node_enum) {
  +const SyntaxTreeNode& CheckNodeEnum(const SyntaxTreeNode& node,
  + E expected_node_enum) {
  // Uses operator<<(std::ostream&, E) for diagnostics.
  - CHECK_EQ(E(node.Tag().tag), node_enum);
  + CHECK_EQ(E(node.Tag().tag), expected_node_enum);
  return node;
  }
  // Mutable variant.
  template <typename E>
  -SyntaxTreeNode& CheckNodeEnum(SyntaxTreeNode& node, E node_enum) {
  +SyntaxTreeNode& CheckNodeEnum(SyntaxTreeNode& node, E expected_node_enum) {
  // Uses operator<<(std::ostream&, E) for diagnostics.
  - CHECK_EQ(E(node.Tag().tag), node_enum);
  + CHECK_EQ(E(node.Tag().tag), expected_node_enum);
  return node;
  }
  template <typename E>
  -const SyntaxTreeLeaf& CheckLeafEnum(const SyntaxTreeLeaf& leaf, E token_enum) {
  +const SyntaxTreeLeaf& CheckLeafEnum(const SyntaxTreeLeaf& leaf,
  + E expected_token_enum) {
  // Uses operator<<(std::ostream&, E) for diagnostics.
  - CHECK_EQ(E(leaf.get().token_enum), token_enum);
  + CHECK_EQ(E(leaf.get().token_enum), expected_token_enum);
  return leaf;
  }
  