Add data structures to AST to indicate potentially mutated variables.

pkg/analyzer/lib/dart/ast/ast.dart

Index: pkg/analyzer/lib/dart/ast/ast.dart
diff --git a/pkg/analyzer/lib/dart/ast/ast.dart b/pkg/analyzer/lib/dart/ast/ast.dart
index 8e295f2c3410800bceda00ca30cc2bbf0722e98b..598d6116c181de35f372ced023f6d874991cd3c9 100644
--- a/pkg/analyzer/lib/dart/ast/ast.dart
+++ b/pkg/analyzer/lib/dart/ast/ast.dart
@@ -536,7 +536,7 @@ abstract class AstNode {
    * (either AST nodes or tokens) that make up the contents of this node,
    * including doc comments but excluding other comments.
    */
-  Iterable/*<AstNode | Token>*/ get childEntities;
+  Iterable /*<AstNode | Token>*/ get childEntities;
 
   /**
    * Return the offset of the character immediately following the last character
@@ -591,7 +591,7 @@ abstract class AstNode {
    * Use the given [visitor] to visit this node. Return the value returned by
    * the visitor as a result of visiting this node.
    */
-  dynamic /* =E */ accept/*<E>*/(AstVisitor/*<E>*/ visitor);
+  dynamic /* =E */ accept /*<E>*/ (AstVisitor /*<E>*/ visitor);
 
   /**
    * Return the most immediate ancestor of this node for which the [predicate]
@@ -3780,6 +3780,32 @@ abstract class FunctionBody extends AstNode {
    * is no star.
    */
   Token get star;
+
+  /**
+   * If [variable] is a local variable or parameter declared anywhere within
+   * the top level function or method containing this [FunctionBody], return a
+   * boolean indicating whether [variable] is potentially mutated within a
+   * local function other than the function in which it is declared.
+   *
+   * If [variable] is not a local variable or parameter declared within the top
+   * level function or method containing this [FunctionBody], return `false`.
+   *
+   * Throws an exception if resolution has not yet been performed.
+   */
+  bool isPotentiallyMutatedInClosure(VariableElement variable);
+
+  /**
+   * If [variable] is a local variable or parameter declared anywhere within
+   * the top level function or method containing this [FunctionBody], return a
+   * boolean indicating whether [variable] is potentially mutated within the
+   * scope of its declaration.
+   *
+   * If [variable] is not a local variable or parameter declared within the top
+   * level function or method containing this [FunctionBody], return `false`.
+   *
+   * Throws an exception if resolution has not yet been performed.
+   */
+  bool isPotentiallyMutatedInScope(VariableElement variable);
 }
 
 /**