unnecessary_constructor_name  
            
            Unnecessary .new constructor name.
This rule is available as of Dart 2.15.0.
Rule sets: recommended, flutter
This rule has a quick fix available.
Details
PREFER using the default unnamed Constructor over .new.
Given a class C, the named unnamed constructor C.new refers to the same
constructor as the unnamed C. As such it adds nothing but visual noise to
invocations and should be avoided (unless being used to identify a constructor
tear-off).
BAD:
class A {
  A.new(); // LINT
}
var a = A.new(); // LINT
GOOD:
class A {
  A.ok();
}
var a = A();
var aa = A.ok();
var makeA = A.new;
Usage
To enable the unnecessary_constructor_name rule,
add unnecessary_constructor_name under linter > rules in your
analysis_options.yaml
file:
linter:
  rules:
    - unnecessary_constructor_name