What is the purpose and use of the Never construct in programming?

In the Dart language (used in Flutter), the Never type indicates a value that is never returned. This means that a function with a return type of Never either runs indefinitely (for example, an infinite loop) or throws an exception and does not terminate normally.

Purpose of Never:

• Explicitly indicates that the function will not return control to the caller.
• Helps the compiler analyze and optimize the code better.
• Used for functions that always throw an exception or terminate the program.

Example:

Never throwError(String message) {
  throw Exception(message);
}

void main() {
  throwError("Error!");
  // Code below is unreachable
}

Here, throwError never returns control, so its type is Never. This helps avoid warnings about unreachable code and improves readability.