# MirrorsUsed class

Annotation describing how "dart:mirrors" is used (EXPERIMENTAL).

When used as metadata on an import of "dart:mirrors" in library L, this class describes how "dart:mirrors" is used by library L unless overridden. See override.

The following text is non-normative:

In some scenarios, for example, when minifying Dart code, or when generating JavaScript code from a Dart program, the size and performance of the output can suffer from use of reflection. In those cases, telling the compiler what is used, can have a significant impact.

Example usage:

    @MirrorsUsed(symbols: 'foo')
    import 'dart:mirrors';

    class Foo {
      noSuchMethod(Invocation invocation) {
        print(MirrorSystem.getName(invocation.memberName));
      }
    }

    main() {
      new Foo().foo(); // Prints "foo".
      new Foo().bar(); // Might print an arbitrary (mangled) name, "bar".
    }

For a detailed description of the parameters to the MirrorsUsed constructor see the comments for symbols, targets, metaTargets and override.

An import of `dart:mirrors` may have multiple MirrorsUsed annotations. This is particularly helpful to specify overrides for specific libraries. For example:

    @MirrorsUsed(targets: 'foo.Bar', override: 'foo')
    @MirrorsUsed(targets: 'Bar')
    import 'dart:mirrors';

will ensure that the target `Bar` from the current library and from library `foo` is available for reflection. See also override.

Annotations
  - @Deprecated("No longer has any effect. Will be removed in a later release.")

## Constructors

MirrorsUsed({dynamic symbols, dynamic targets, dynamic metaTargets, dynamic override })
  See the documentation for MirrorsUsed.symbols, MirrorsUsed.targets, MirrorsUsed.metaTargets and MirrorsUsed.override for documentation of the parameters.
  const

## Properties

metaTargets → dynamic
  A list of classes that when used as metadata indicates a reflective target. See also `targets`. [...]
  final
override → dynamic
  A list of library names or "*". [...]
  final
symbols → dynamic
  The list of strings passed to new `Symbol`, and symbols that might be passed to `MirrorSystem.getName`. [...]
  final
targets → dynamic
  A list of reflective targets. [...]
  final
hashCode → int
  The hash code for this object. [...]
  read-only, inherited
runtimeType → Type
  A representation of the runtime type of the object.
  read-only, inherited

## Methods

noSuchMethod(Invocation invocation) → dynamic
  Invoked when a non-existent method or property is accessed. [...]
  inherited
toString() → String
  Returns a string representation of this object.
  inherited

## Operators

operator ==(dynamic other) → bool
  The equality operator. [...]
  inherited