/*
 * Copyright 2009 The Closure Compiler Authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.javascript.jscomp;

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.javascript.rhino.IR;
import com.google.javascript.rhino.InputId;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.StaticSourceFile.SourceKind;

/**
 * An AST generated totally by the compiler.
 *
 * @author nicksantos@google.com (Nick Santos)
 */
public final class SyntheticAst implements SourceAst {
  private static final long serialVersionUID = 1L;

  private final InputId inputId;
  private final SourceFile sourceFile;

  private Node root;

  SyntheticAst(String sourceName) {
    this.inputId = new InputId(sourceName);
    this.sourceFile = new SourceFile(sourceName, SourceKind.STRONG);
    clearAst();
  }

  public SyntheticAst(Node root) {
    this.inputId = new InputId(root.getSourceFileName());
    this.sourceFile = new SourceFile(root.getSourceFileName(), SourceKind.STRONG);
    this.root = checkNotNull(root);
  }

  @Override
  public Node getAstRoot(AbstractCompiler compiler) {
    return root;
  }

  @Override
  public void clearAst() {
    root = IR.script();
    root.setInputId(inputId);
    root.setStaticSourceFile(sourceFile);
  }

  @Override
  public InputId getInputId() {
    return inputId;
  }

  @Override
  public SourceFile getSourceFile() {
    return sourceFile;
  }

  @Override
  public void setSourceFile(SourceFile file) {
    throw new IllegalStateException(
        "Cannot set a source file for a synthetic AST");
  }
}

@@ -712,16 +712,72 @@
 tNull;%0A%0A
+import com.google.common.annotations.VisibleForTesting;%0A
 import c
@@ -1262,16 +1262,151 @@
  root;%0A%0A
+  @VisibleForTesting%0A  public static SyntheticAst emptyWithFileName(String sourceName) %7B%0A    return new SyntheticAst(sourceName);%0A  %7D%0A%0A
   Synthe

Make the SyntheticAst(String) constructor visible for testing.