[psi-based formatting] place space before empty element if it's left bound and first child of it's parent (since bounds works only for child on the same level), fixes IDEA-158868

java/java-tests/testSrc/com/intellij/psi/formatter/java/JavaPsiFormattingTest.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2000-2016 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.formatter.java;
+
+import com.intellij.openapi.application.WriteAction;
+import com.intellij.openapi.command.CommandProcessor;
+import com.intellij.openapi.util.Ref;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiExpression;
+import com.intellij.psi.PsiFile;
+import com.intellij.psi.PsiIfStatement;
+import com.intellij.psi.codeStyle.CodeStyleManager;
+import com.intellij.psi.impl.DebugUtil;
+import com.intellij.psi.util.PsiTreeUtil;
+
+public class JavaPsiFormattingTest extends AbstractJavaFormatterTest {
+  
+  public void testReferenceExpressionSpaceInsertion() {
+    String text = "if(x&y);";
+    PsiFile file = createFile("A.java", "class C{{\n" + text + "\n}}");
+    PsiElement element = file.findElementAt(file.getText().indexOf(text));
+    PsiIfStatement statement = PsiTreeUtil.getParentOfType(element, PsiIfStatement.class);
+    assertNotNull(statement);
+
+    Ref<PsiElement> result = Ref.create();
+    CommandProcessor.getInstance().executeCommand(getProject(), () -> WriteAction.run(
+      () -> result.set(CodeStyleManager.getInstance(getProject()).reformat(statement))
+    ), "", null);
+
+    PsiExpression expr = ((PsiIfStatement)result.get()).getCondition();
+    assertEquals("PsiBinaryExpression:x & y\n" +
+                 "  PsiReferenceExpression:x\n" +
+                 "    PsiReferenceParameterList\n" +
+                 "      <empty list>\n" +
+                 "    PsiIdentifier:x('x')\n" +
+                 "  PsiWhiteSpace(' ')\n" +
+                 "  PsiJavaToken:AND('&')\n" +
+                 "  PsiWhiteSpace(' ')\n" +
+                 "  PsiReferenceExpression:y\n" +
+                 "    PsiReferenceParameterList\n" +
+                 "      <empty list>\n" +
+                 "    PsiIdentifier:y('y')\n",
+                 DebugUtil.psiToString(expr, false));
+  }
+  
+}

platform/lang-impl/src/com/intellij/psi/formatter/FormatterUtil.java

@@ -378,7 +378,7 @@ public class FormatterUtil {
       if (treePrev.getElementType() == TokenType.WHITE_SPACE) {
         return treePrev;
       }
-      else if (treePrev.getTextLength() == 0 && !treePrev.getElementType().isLeftBound()) {
+      else if (treePrev.getTextLength() == 0 && isSpaceBeforeEmptyElement(treePrev)) {
         return getWsCandidate(treePrev);
       }
       else {
@@ -395,6 +395,14 @@ public class FormatterUtil {
     }
   }
 
+  private static boolean isSpaceBeforeEmptyElement(ASTNode node) {
+    if (node.getElementType().isLeftBound()) {
+      final ASTNode parent = node.getTreeParent();
+      return parent != null && parent.getFirstChildNode() == node;
+    }
+    return true;
+  }
+
   private static StringBuilder createNewLeafChars(final ASTNode leafElement, final TextRange textRange, final String whiteSpace) {
     final TextRange elementRange = leafElement.getTextRange();
     final String elementText = leafElement.getText();