Consider generating code compliant with implicit-dynamic: false

[knaeckeKami]

Context:

A dart project can contain an analysis_options.yaml file that enables stricter type checking.
One of these options is
implicit-dynamic: false
which will prevent the compiler from inferring dynamic unless it's explicitly annotated.

I propose changes to make the moor generator compatible with these stricter type checks.
They might be enabled by default in the future, anyway.
A somewhat related option
implicit-casts: false will be enabled by default, when NNBD lands. ( see dart-lang/sdk#31410 (comment) ).

Projects that use implicit-dynamic: false and moor_generator currently need to exclude generated files from this rule ( e.g. by using exclude: [ lib/**/*.g.dart] in their analysis_options.yaml).
If this rule becomes the default in the future, all users of moor_generator would need to exclude thee files generated by moor_generator.

The steps needed to make the code compliant would be.

1. change the generated == methods from

bool operator ==(other) {

to

bool operator ==(Object other) {

2. change the generated toJson() methods from

@override
Map<String, dynamic> toJson(
      {ValueSerializer serializer = const ValueSerializer.defaults()}) {
    return {
      'key': serializer.toJson<String>(key),
      ...
    };
}

to

@override
Map<String, dynamic> toJson(
      {ValueSerializer serializer = const ValueSerializer.defaults()}) {
    return <String, dynamic>{
      'key': serializer.toJson<String>(key),
      ...
    };
}

[simolus3]

Thanks for the request and the detailed description. With the next generator release, the code will be compliant with implicit-dynamic: false. See also #268.

[knaeckeKami]

Oh, sorry for the duplicate, I missed #268 somehow, even though it's worded nearly identical.