Move definition of Feature next to definitions of WorldImpact and Use

pkg/compiler/lib/src/universe/feature.dart

+// TODO(sigmund): rename universe => world
+/// Describes individual features that may be seen in a program. Most features
+/// can be described only by name using the [Feature] enum, some features are
+/// expressed including details on how they are used. For example, whether a
+/// list literal was constant or empty.
+///
+/// The use of these features is typically discovered in an early phase of the
+/// compilation pipeline, for example during resolution.
+library compiler.universe.feature;
+
+import '../dart_types.dart' show InterfaceType;
+
+/// A language feature that may be seen in the program.

[Siggi Cherem (dart-lang), 2016/08/16 18:21:51]

FYI - I updated the library and class docs (see original descriptions in
common/resolution.dart)

+// TODO(johnniwinther): Should mirror usage be part of this?
+enum Feature {
+  /// Invocation of a generative construction on an abstract class.
+  ABSTRACT_CLASS_INSTANTIATION,
+
+  /// An assert statement with no message.
+  ASSERT,
+
+  /// An assert statement with a message.
+  ASSERT_WITH_MESSAGE,
+
+  /// A method with an `async` body modifier.
+  ASYNC,
+
+  /// An asynchronous for in statement like `await for (var e in i) {}`.
+  ASYNC_FOR_IN,
+
+  /// A method with an `async*` body modifier.
+  ASYNC_STAR,
+
+  /// A catch statement.
+  CATCH_STATEMENT,
+
+  /// A compile time error.
+  COMPILE_TIME_ERROR,
+
+  /// A fall through in a switch case.
+  FALL_THROUGH_ERROR,
+
+  /// A ++/-- operation.
+  INC_DEC_OPERATION,
+
+  /// A field whose initialization is not a constant.
+  LAZY_FIELD,
+
+  /// A catch clause with a variable for the stack trace.
+  STACK_TRACE_IN_CATCH,
+
+  /// String interpolation.
+  STRING_INTERPOLATION,
+
+  /// String juxtaposition.
+  STRING_JUXTAPOSITION,
+
+  /// An implicit call to `super.noSuchMethod`, like calling an unresolved
+  /// super method.
+  SUPER_NO_SUCH_METHOD,
+
+  /// A redirection to the `Symbol` constructor.
+  SYMBOL_CONSTRUCTOR,
+
+  /// An synchronous for in statement, like `for (var e in i) {}`.
+  SYNC_FOR_IN,
+
+  /// A method with a `sync*` body modifier.
+  SYNC_STAR,
+
+  /// A throw expression.
+  THROW_EXPRESSION,
+
+  /// An implicit throw of a `NoSuchMethodError`, like calling an unresolved
+  /// static method.
+  THROW_NO_SUCH_METHOD,
+
+  /// An implicit throw of a runtime error, like
+  THROW_RUNTIME_ERROR,
+
+  /// The need for a type variable bound check, like instantiation of a generic
+  /// type whose type variable have non-trivial bounds.
+  TYPE_VARIABLE_BOUNDS_CHECK,
+}
+
+/// Describes a use of a map literal in the program.
+class MapLiteralUse {
+  final InterfaceType type;
+  final bool isConstant;
+  final bool isEmpty;
+
+  MapLiteralUse(this.type, {this.isConstant: false, this.isEmpty: false});
+
+  int get hashCode {
+    return type.hashCode * 13 +
+        isConstant.hashCode * 17 +
+        isEmpty.hashCode * 19;
+  }
+
+  bool operator ==(other) {
+    if (identical(this, other)) return true;
+    if (other is! MapLiteralUse) return false;
+    return type == other.type &&
+        isConstant == other.isConstant &&
+        isEmpty == other.isEmpty;
+  }
+
+  String toString() {
+    return 'MapLiteralUse($type,isConstant:$isConstant,isEmpty:$isEmpty)';
+  }
+}
+
+/// Describes the use of a list literal in the program.
+class ListLiteralUse {
+  final InterfaceType type;
+  final bool isConstant;
+  final bool isEmpty;
+
+  ListLiteralUse(this.type, {this.isConstant: false, this.isEmpty: false});
+
+  int get hashCode {
+    return type.hashCode * 13 +
+        isConstant.hashCode * 17 +
+        isEmpty.hashCode * 19;
+  }
+
+  bool operator ==(other) {
+    if (identical(this, other)) return true;
+    if (other is! ListLiteralUse) return false;
+    return type == other.type &&
+        isConstant == other.isConstant &&
+        isEmpty == other.isEmpty;
+  }
+
+  String toString() {
+    return 'ListLiteralUse($type,isConstant:$isConstant,isEmpty:$isEmpty)';
+  }
+}