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pkg/compiler/lib/src/kernel/fall_through_visitor.dart

-// Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE.md file.
-
-import 'package:kernel/ast.dart'
-    show
-        AssertStatement,
-        Block,
-        BreakStatement,
-        Catch,
-        ContinueSwitchStatement,
-        DoStatement,
-        EmptyStatement,
-        ExpressionStatement,
-        ForInStatement,
-        ForStatement,
-        FunctionDeclaration,
-        IfStatement,
-        InvalidStatement,
-        LabeledStatement,
-        ReturnStatement,
-        Statement,
-        StatementVisitor,
-        SwitchStatement,
-        Throw,
-        TryCatch,
-        TryFinally,
-        VariableDeclaration,
-        WhileStatement,
-        YieldStatement;
-
-/// Returns true if [node] would let execution reach the next node (aka
-/// fall-through in switch cases).
-bool fallsThrough(Statement node) => node.accept(const FallThroughVisitor());
-
-/// Visitor implementing [computeFallThrough].
-class FallThroughVisitor implements StatementVisitor<bool> {
-  const FallThroughVisitor();
-
-  bool defaultStatement(Statement node) => throw "Not implemented.";
-
-  bool visitInvalidStatement(InvalidStatement node) => false;
-
-  bool visitExpressionStatement(ExpressionStatement node) {
-    return node.expression is! Throw;
-  }
-
-  bool visitBlock(Block node) {
-    for (Statement statement in node.statements) {
-      if (!statement.accept(this)) return false;
-    }
-    return true;
-  }
-
-  bool visitEmptyStatement(EmptyStatement node) => true;
-
-  bool visitAssertStatement(AssertStatement node) => true;
-
-  bool visitLabeledStatement(LabeledStatement node) => true;
-
-  bool visitBreakStatement(BreakStatement node) => false;
-
-  bool visitWhileStatement(WhileStatement node) => true;
-
-  bool visitDoStatement(DoStatement node) => node.body.accept(this);
-
-  bool visitForStatement(ForStatement node) => true;
-
-  bool visitForInStatement(ForInStatement node) => true;
-
-  bool visitSwitchStatement(SwitchStatement node) => true;
-
-  bool visitContinueSwitchStatement(ContinueSwitchStatement node) => false;
-
-  bool visitIfStatement(IfStatement node) {
-    if (node.then == null || node.otherwise == null) return true;
-    return node.then.accept(this) || node.otherwise.accept(this);
-  }
-
-  bool visitReturnStatement(ReturnStatement node) => false;
-
-  bool visitTryCatch(TryCatch node) {
-    if (node.body.accept(this)) return true;
-    for (Catch catchNode in node.catches) {
-      if (catchNode.body.accept(this)) return true;
-    }
-    return false;
-  }
-
-  bool visitTryFinally(TryFinally node) {
-    return node.body.accept(this) && node.finalizer.accept(this);
-  }
-
-  bool visitYieldStatement(YieldStatement node) => true;
-
-  bool visitVariableDeclaration(VariableDeclaration node) => true;
-
-  bool visitFunctionDeclaration(FunctionDeclaration node) => true;
-}