- String message
A lint enforces that this constructor can only be called with a string literal to match the limitations of the Dart Kernel transformer that optionally extracts out objects referenced using string interpolation in the message passed in.
The message will display with the same text regardless of whether the kernel transformer is used. The kernel transformer is required so that debugging tools can provide interactive displays of objects described by the error.
ErrorSummary(String message) : super(message, level: DiagnosticLevel.summary);