Record field names can't be a dollar sign followed by an integer when the integer is the index of a positional field. Record field names can't be private. Record field names can't be the same as a member from 'Object'DRT-W1420

The analyzer produces this diagnostic when either a record literal or a record type annotation has a field whose name is invalid. The name is invalid if it is:

• private (starts with _)
• the same as one of the members defined on Object
• the same as the name of a positional field (an exception is made if the field is a positional field with the specified name)

Examples

The following code produces this diagnostic because the record literal has a field named toString, which is a method defined on Object:

var r = (a: 1, toString: 4);

The following code produces this diagnostic because the record type annotation has a field named hashCode, which is a getter defined on Object:

void f(({int a, int hashCode}) r) {}

The following code produces this diagnostic because the record literal has a private field named _a:

var r = (_a: 1, b: 2);

The following code produces this diagnostic because the record type annotation has a private field named _a:

void f(({int _a, int b}) r) {}

The following code produces this diagnostic because the record literal has a field named $1, which is also the name of a different positional parameter:

var r = (2, $1: 1);

The following code produces this diagnostic because the record type annotation has a field named $1, which is also the name of a different positional parameter:

void f((int, String, {int $1}) r) {}

Common fixes

Rename the field:

var r = (a: 1, d: 4);