code: function isForInVariableForNumericPropertyNames(expr) {
              var e = skipParenthesizedNodes(expr);
              if (e.kind === 69 /* Identifier */) {
                  var symbol = getResolvedSymbol(e);
                  if (symbol.flags & 3 /* Variable */) {
                      var child = expr;
                      var node = expr.parent;
                      while (node) {
                          if (node.kind === 207 /* ForInStatement */ &&
                              child === node.statement &&
                              getForInVariableSymbol(node) === symbol &&
                              hasNumericPropertyNames(checkExpression(node.expression))) {
                              return true;
                          }
                          child = node;
                          node = node.parent;
                      }
                  }
              }
              return false;
          }
docs: Return true if given node is an expression consisting of an identifier (possibly parenthesized)
  that references a for-in variable for an object with numeric property names.