avoid-unnecessary-type-casts

// Test cases for avoid-unnecessary-type-casts rule
// Flags 'as T' casts where the variable is already T

void testCastExplicitIntType() {
  final int x = 5;
  final y = x as int;
}

void testCastExplicitStringType() {
  final String name = "hello";
  final result = name as String;
}

void testCastExplicitListType() {
  final List<String> items = [];
  final casted = items as List<String>;
}

void testMultipleUnnecessaryCasts() {
  final bool active = true;
  final double value = 3.14;

  final a = active as bool;
  final b = value as double;
}

class MyClass {
  final int id = 42;

  void castId() {
    final casted = id as int;
    print(casted);
  }
}

void testInlineUnnecessaryCast() {
  final String message = "test";
  final length = (message as String).length;
}

void testChainedUnnecessaryCast() {
  final Map<String, int> data = {};
  final result = data as Map<String, int>;
}

// Regression: the cast must still be found inside Dart 3 containers.
void testCastsInContainers() {
  final int n = 5;
  final (a, _) = (n as int, 0);
  lbl: {
    final b = n as int;
    print(b);
  }
  final c = switch (n) {
    0 => n as int,
    _ => 0,
  };
  final d = switch (n as int) {
    _ => 0,
  };
  final e = [if (n > 0) n as int];
  final f = [...[n as int]];
  final g = (p: n as int, q: 0);
  print([a, c, d, e, f, g]);
}

// Regression: locals declared inside a loop or a try body are tracked, so a
// redundant cast there is still reported.
void loopScopeRegression(List<int> xs) {
  for (final _ in xs) {
    final int inLoop = 1;
    print(inLoop as int);
  }
  try {
    final int inTry = 2;
    print(inTry as int);
  } catch (e) {
    print(e);
  }
}

void typedCollectionForCastRegression() {
  final list = [
    for (int i = 0; i < 2; i++) i as int,
  ];
  final map = {
    for (int j = 0; j < 2; j++) j: j as int,
  };
  print([list, map]);
}

// Initializing an `int?` local with an `int` promotes it to `int`; Dart 3.13.5
// `dart analyze` reports unnecessary_cast here.
void testCastPromotedOnInitialization() {
  int? maybeInt = 5;
  final int nonNull = maybeInt as int;
  print(nonNull);
}