IDEA-153437 Do not suggest to loop over the loop variable (and don't duplicate "new")

java/java-impl/src/com/intellij/codeInsight/completion/ExcludeFilter.java

@@ -0,0 +1,43 @@
+/*
+ * 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.codeInsight.completion;
+
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiVariable;
+import com.intellij.psi.filters.ElementFilter;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * @author peter
+ */
+class ExcludeFilter implements ElementFilter {
+  private final PsiElement myExcluded;
+
+  public ExcludeFilter(@NotNull PsiVariable excluded) {
+    myExcluded = excluded;
+  }
+
+  @Override
+  public boolean isAcceptable(Object element, @Nullable PsiElement context) {
+    return element != myExcluded;
+  }
+
+  @Override
+  public boolean isClassAcceptable(Class hintClass) {
+    return true;
+  }
+}

java/java-impl/src/com/intellij/codeInsight/completion/JavaCompletionContributor.java

@@ -43,7 +43,6 @@ import com.intellij.psi.codeStyle.CodeStyleManager;
 import com.intellij.psi.filters.*;
 import com.intellij.psi.filters.classes.AnnotationTypeFilter;
 import com.intellij.psi.filters.classes.AssignableFromContextFilter;
-import com.intellij.psi.filters.element.ExcludeDeclaredFilter;
 import com.intellij.psi.filters.element.ModifierFilter;
 import com.intellij.psi.filters.getters.ExpectedTypesGetter;
 import com.intellij.psi.impl.source.PsiJavaCodeReferenceElementImpl;
@@ -158,7 +157,7 @@ public class JavaCompletionContributor extends CompletionContributor {
 
     PsiVariable var = PsiTreeUtil.getParentOfType(position, PsiVariable.class, false, PsiClass.class);
     if (var != null && PsiTreeUtil.isAncestor(var.getInitializer(), position, false)) {
-      return new ExcludeDeclaredFilter(new ClassFilter(PsiVariable.class));
+      return new ExcludeFilter(var);
     }
 
     if (SWITCH_LABEL.accepts(position)) {
@@ -170,6 +169,11 @@ public class JavaCompletionContributor extends CompletionContributor {
       };
     }
 
+    PsiForeachStatement loop = PsiTreeUtil.getParentOfType(position, PsiForeachStatement.class);
+    if (loop != null && PsiTreeUtil.isAncestor(loop.getIteratedValue(), position, false)) {
+      return new ExcludeFilter(loop.getIterationParameter());
+    }
+
     return TrueFilter.INSTANCE;
   }
 

java/java-impl/src/com/intellij/codeInsight/completion/JavaKeywordCompletion.java

@@ -251,7 +251,8 @@ public class JavaKeywordCompletion {
     PsiElement prevLeaf = PsiTreeUtil.prevVisibleLeaf(position);
     addFinal(result, position, prevLeaf);
 
-    if (isStatementPosition(position)) {
+    boolean statementPosition = isStatementPosition(position);
+    if (statementPosition) {
       addCaseDefault(result, position);
       if (START_SWITCH.accepts(position)) {
         return;
@@ -263,7 +264,7 @@ public class JavaKeywordCompletion {
 
     addThisSuper(result, position);
 
-    addExpressionKeywords(parameters, result, position, prevLeaf);
+    addExpressionKeywords(parameters, result, position, prevLeaf, statementPosition);
 
     addFileHeaderKeywords(result, position, prevLeaf);
 
@@ -358,7 +359,7 @@ public class JavaKeywordCompletion {
     }
   }
 
-  private static void addExpressionKeywords(CompletionParameters parameters, Consumer<LookupElement> result, PsiElement position, @Nullable PsiElement prevLeaf) {
+  private static void addExpressionKeywords(CompletionParameters parameters, Consumer<LookupElement> result, PsiElement position, @Nullable PsiElement prevLeaf, boolean statementPosition) {
     if (psiElement(JavaTokenType.DOUBLE_COLON).accepts(prevLeaf)) {
       PsiMethodReferenceExpression parent = PsiTreeUtil.getParentOfType(parameters.getPosition(), PsiMethodReferenceExpression.class);
       TailType tail = parent != null && !LambdaHighlightingUtil.insertSemicolon(parent.getParent()) ? TailType.SEMICOLON : TailType.NONE;
@@ -368,7 +369,9 @@ public class JavaKeywordCompletion {
 
     if (isExpressionPosition(position)) {
       if (PsiTreeUtil.getParentOfType(position, PsiAnnotation.class) == null) {
-        result.consume(TailTypeDecorator.withTail(createKeyword(position, PsiKeyword.NEW), TailType.INSERT_SPACE));
+        if (!statementPosition) {
+          result.consume(TailTypeDecorator.withTail(createKeyword(position, PsiKeyword.NEW), TailType.INSERT_SPACE));
+        }
         result.consume(createKeyword(position, PsiKeyword.NULL));
       }
       if (mayExpectBoolean(parameters)) {

java/java-tests/testData/codeInsight/completion/variables/DontIterateOverLoopVariable.java

@@ -0,0 +1,12 @@
+import java.util.ArrayList;
+
+public class Test {
+  {
+
+    ArrayList<Node> nodes = new ArrayList<>();
+    for (Node n : n<caret>)
+  }
+
+}
+
+class Node {}

java/java-tests/testSrc/com/intellij/codeInsight/completion/VariablesCompletionTest.groovy

@@ -167,6 +167,11 @@ public class VariablesCompletionTest extends LightFixtureCompletionTestCase {
     assertStringItems("stringBuffer", "buffer");
   }
 
+  public void testDontIterateOverLoopVariable() throws Throwable {
+    configure()
+    myFixture.assertPreferredCompletionItems 0, 'nodes', 'new', 'null'
+  }
+
   public void testDuplicateSuggestionsFromUsage() {
     configure();
     assertStringItems("preferencePolicy", "policy", "aPreferencePolicy");