.analysis_options

analyzer:
  strong-mode: true
linter:
  rules:
    - always_declare_return_types
    - always_specify_types
    - annotate_overrides
    - avoid_as
    - avoid_empty_else
    - avoid_init_to_null
    - avoid_return_types_on_setters
    - await_only_futures
    - camel_case_types
    - cancel_subscriptions
    - close_sinks
    - comment_references
    - constant_identifier_names
    - control_flow_in_finally
    - empty_catches
    - empty_constructor_bodies
    - empty_statements
    - hash_and_equals
    - implementation_imports
    - iterable_contains_unrelated_type
    - library_names
    - library_prefixes
    - list_remove_unrelated_type
    - non_constant_identifier_names
    - one_member_abstracts
    - only_throw_errors
    - overridden_fields
    - package_api_docs
    - package_names
    - package_prefixed_library_names
    - prefer_is_not_empty
    - public_member_api_docs
    - slash_for_doc_comments
    - sort_constructors_first
    - sort_unnamed_constructors_first
    - super_goes_last
    - test_types_in_equals
    - throw_in_finally
    - type_annotate_public_apis
    - type_init_formals
    - unawaited_futures
    - unnecessary_brace_in_string_interp
    - unnecessary_getters_setters
    - unrelated_type_equality_checks
    - valid_regexps

README.md

• copy these files into a new directory (make sure lib_main.dart is placed in lib/main.dart)

• make sure you have a copy of flutter cloned and the tools on your path

• run dartanalyzer lib/main.dart and notice NO WARNINGS

• run flutter packages get

• run dartanalyzer lib/main.dart and notice WARNINGS

• open .packages

• comment out the line for sky_engine

• run dartanalyzer lib/main.dart and notice NO WARNINGS

For some reason, including sky_engine in your .packages is enough to trigger the warning.

lib_main.dart

class Foo {}
class Bar extends Foo {
  Bar(f) {}
}

main() {
  List<Foo> fooList = <Foo>[new Foo(), new Foo(), new Foo()];
  List<Bar> barList = fooList.map((Foo f) => new Bar(f)).toList();
  print(barList);
}

pubspec.yaml

name: repocase
dependencies:
  flutter:
    sdk: flutter