/*
 * Copyright 2000-2009 JetBrains s.r.o.
 *
 * 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.intellij.psi.impl.source.tree.java;

import com.intellij.lang.ASTNode;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.psi.*;
import com.intellij.psi.impl.DebugUtil;
import com.intellij.psi.impl.source.SourceTreeToPsiMap;
import com.intellij.psi.impl.source.tree.*;
import com.intellij.psi.tree.ChildRoleBase;
import com.intellij.psi.tree.IElementType;
import org.jetbrains.annotations.NotNull;

public class PsiExpressionStatementImpl extends CompositePsiElement implements PsiExpressionStatement {
  private static final Logger LOG = Logger.getInstance(PsiExpressionStatementImpl.class);

  public PsiExpressionStatementImpl() {
    super(JavaElementType.EXPRESSION_STATEMENT);
  }

  @Override
  @NotNull
  public PsiExpression getExpression() {
    PsiExpression expression = (PsiExpression)SourceTreeToPsiMap.treeElementToPsi(findChildByType(ElementType.EXPRESSION_BIT_SET));
    if (expression != null) return expression;
    LOG.error("Illegal PSI: \n" + DebugUtil.psiToString(getParent(), false));
    return null;
  }

  @Override
  public ASTNode findChildByRole(int role) {
    LOG.assertTrue(ChildRole.isUnique(role));
    switch(role){
      default:
        return null;

      case ChildRole.EXPRESSION:
        return findChildByType(ElementType.EXPRESSION_BIT_SET);

      case ChildRole.CLOSING_SEMICOLON:
        return TreeUtil.findChildBackward(this, JavaTokenType.SEMICOLON);
    }
  }

  @Override
  public int getChildRole(@NotNull ASTNode child) {
    LOG.assertTrue(child.getTreeParent() == this);
    IElementType i = child.getElementType();
    if (i == JavaTokenType.SEMICOLON) {
      return ChildRole.CLOSING_SEMICOLON;
    }
    else {
      if (ElementType.EXPRESSION_BIT_SET.contains(child.getElementType())) {
        return ChildRole.EXPRESSION;
      }
      return ChildRoleBase.NONE;
    }
  }

  @Override
  public void accept(@NotNull PsiElementVisitor visitor) {
    if (visitor instanceof JavaElementVisitor) {
      ((JavaElementVisitor)visitor).visitExpressionStatement(this);
    }
    else {
      visitor.visitElement(this);
    }
  }

  @Override
  public String toString() {
    return "PsiExpressionStatement";
  }

  @Override
  public void deleteChildInternal(@NotNull ASTNode child) {
    if (getChildRole(child) == ChildRole.EXPRESSION) {
      getTreeParent().deleteChildInternal(this);
    }
    else {
      super.deleteChildInternal(child);
    }
  }
}

@@ -978,16 +978,70 @@
 ntType;%0A
+import com.intellij.util.IncorrectOperationException;%0A
 import o
@@ -3088,11 +3088,440 @@
    %7D%0A  %7D
+%0A%0A  @Override%0A  public void replaceChildInternal(@NotNull ASTNode child, @NotNull TreeElement newElement) %7B%0A    if (ElementType.EXPRESSION_BIT_SET.contains(child.getElementType()) &&%0A        !ElementType.EXPRESSION_BIT_SET.contains(newElement.getElementType())) %7B%0A      throw new IncorrectOperationException(%22Expression expected; got: %22 + newElement.getElementType());%0A    %7D%0A    super.replaceChildInternal(child, newElement);%0A  %7D
 %0A%7D%0A

Validate replaced child in PsiExpressionStatementImpl