omit_obvious_local_variable_types

Omit obvious type annotations for local variables.

此规则目前处于 experimental 状态，自 Dart 3.6 版本起可用。

此规则提供 快速修复 。

_不兼容规则：always_specify_types _

Don't type annotate initialized local variables when the type is obvious.

Local variables, especially in modern code where functions tend to be small, have very little scope. Omitting the type focuses the reader's attention on the more important name of the variable and its initialized value. Hence, local variable type annotations that are obvious should be omitted.

BAD:

List<List<Ingredient>> possibleDesserts(Set<Ingredient> pantry) {
  List<List<Ingredient>> desserts = <List<Ingredient>>[];
  for (final List<Ingredient> recipe in cookbook) {
    if (pantry.containsAll(recipe)) {
      desserts.add(recipe);
    }
  }

  return desserts;
}

const cookbook = <List<Ingredient>>[....];

GOOD:

List<List<Ingredient>> possibleDesserts(Set<Ingredient> pantry) {
  var desserts = <List<Ingredient>>[];
  for (final List<Ingredient> recipe in cookbook) {
    if (pantry.containsAll(recipe)) {
      desserts.add(recipe);
    }
  }

  return desserts;
}

const cookbook = <List<Ingredient>>[....];

Sometimes the inferred type is not the type you want the variable to have. For example, you may intend to assign values of other types later. You may also wish to write a type annotation explicitly because the type of the initializing expression is non-obvious and it will be helpful for future readers of the code to document this type. Or you may wish to commit to a specific type such that future updates of dependencies (in nearby code, in imports, anywhere) will not silently change the type of that variable, thus introducing compile-time errors or run-time bugs in locations where this variable is used. In those cases, go ahead and annotate the variable with the type you want.

GOOD:

Widget build(BuildContext context) {
  Widget result = someGenericFunction(42) ?? Text('You won!');
  if (applyPadding) {
    result = Padding(padding: EdgeInsets.all(8.0), child: result);
  }
  return result;
}

This rule is experimental. It is being evaluated, and it may be changed or removed. Feedback on its behavior is welcome! The main issue is here: https://github.com/dart-lang/linter/issues/3480.

要启用 omit_obvious_local_variable_types 规则，请在你的 analysis_options.yaml 文件中，在 linter > rules 下添加 omit_obvious_local_variable_types ：

linter:
  rules:
    - omit_obvious_local_variable_types

除非另有说明，否则本网站上的文档反映的是 Dart 3.6.0。页面最后更新于 2025-02-05。 查看源代码 或 报告问题.