literal_only_boolean_expressions

The Boolean expression has a constant value.

The analyzer produces this diagnostic when the value of the condition in an if or loop statement is known to be either always true or always false. An exception is made for a while loop whose condition is the Boolean literal true.

The following code produces this diagnostic because the condition will always evaluate to true:

void f() {
  if (true) {
    print('true');
  }
}

The lint will evaluate a subset of expressions that are composed of constants, so the following code will also produce this diagnostic because the condition will always evaluate to false:

void g(int i) {
  if (1 == 0 || 3 > 4) {
    print('false');
  }
}

If the condition is wrong, then correct the condition so that it's value can't be known at compile time:

void g(int i) {
  if (i == 0 || i > 4) {
    print('false');
  }
}

If the condition is correct, then simplify the code to not evaluate the condition:

void f() {
  print('true');
}

Unless stated otherwise, the documentation on this site reflects Dart 3.8.0. Page last updated on 2025-05-08. View source or report an issue.