const_constructor_param_type_mismatch

A value of type '{0}' can't be assigned to a parameter of type '{1}' in a const constructor.

The analyzer produces this diagnostic when the runtime type of a constant value can't be assigned to the static type of a constant constructor's parameter.

The following code produces this diagnostic because the runtime type of i is int, which can't be assigned to the static type of s:

class C {
  final String s;

  const C(this.s);
}

const dynamic i = 0;

void f() {
  const C(i);
}

Pass a value of the correct type to the constructor:

class C {
  final String s;

  const C(this.s);
}

const dynamic i = 0;

void f() {
  const C('$i');
}

除非另有说明，文档之所提及适用于 Dart 3.7.3 版本，本页面最后更新时间: 2025-05-08。 查看文档源码 或者 报告页面问题。