curly_braces_in_flow_control_structures

DO use curly braces for all flow control structures.

This rule is available as of Dart 2.0.0.

Rule sets: core, recommended, flutter

This rule has a quick fix available.

Details

DO use curly braces for all flow control structures.

Doing so avoids the dangling else problem.

BAD:

if (overflowChars != other.overflowChars)
  return overflowChars < other.overflowChars;

GOOD:

if (isWeekDay) {
  print('Bike to work!');
} else {
  print('Go dancing or read a book!');
}

There is one exception to this: an if statement with no else clause where the entire if statement and the then body all fit in one line. In that case, you may leave off the braces if you prefer:

GOOD:

if (arg == null) return defaultValue;

If the body wraps to the next line, though, use braces:

GOOD:

if (overflowChars != other.overflowChars) {
  return overflowChars < other.overflowChars;
}

Usage

To enable the curly_braces_in_flow_control_structures rule, add curly_braces_in_flow_control_structures under linter > rules in your analysis_options.yaml file:

linter:
  rules:
    - curly_braces_in_flow_control_structures