There's some places where nullable values are compared to bools e.g.:

editable.dart:

    if (selectionEnabled && selection?.isValid == true) {

editable_text.dart:

    return widget.selectionEnabled && copyEnabled && _hasFocus && controls?.canCopy(this) == true

text_selection.dart:

    if (widget.visibility?.value != false) {

There's a lint for this that could be enabled: use_if_null_to_convert_nulls_to_bools.