non_bool_condition

Conditions must have a static type of 'bool'.

The analyzer produces this diagnostic when a condition, such as an if or while loop, doesn't have the static type bool.

The following code produces this diagnostic because x has the static type int:

void f(int x) {
  if (x) {
    // ...
  }
}

Change the condition so that it produces a Boolean value:

void f(int x) {
  if (x == 0) {
    // ...
  }
}

Unless stated otherwise, the documentation on this site reflects Dart 3.8.1. Page last updated on 2025-05-08. View source or report an issue.