MessageProperty constructor Null safety

MessageProperty(
  1. String name,
  2. String message,
  3. {DiagnosticsTreeStyle style = DiagnosticsTreeStyle.singleLine,
  4. DiagnosticLevel level = DiagnosticLevel.info}
)

Create a diagnostics property that displays a message.

Messages have no concrete value (so value will return null). The message is stored as the description.

The name, message, and level arguments must not be null.

Implementation

MessageProperty(
  String name,
  String message, {
  DiagnosticsTreeStyle style = DiagnosticsTreeStyle.singleLine,
  DiagnosticLevel level = DiagnosticLevel.info,
}) : assert(name != null),
     assert(message != null),
     assert(style != null),
     assert(level != null),
     super(name, null, description: message, style: style, level: level);