java completion: suggest same-named fields in scope, add Outer.this. qualifier for instance fields

GitOrigin-RevId: c80f4dc53b13c4851a9c9df9402198f1d1b48c26

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

@@ -563,7 +563,7 @@ public class JavaCompletionUtil {
       return Collections.singletonList(item);
     }
     if (completion instanceof PsiVariable) {
-      return Collections.singletonList(new VariableLookupItem((PsiVariable)completion).setSubstitutor(substitutor));
+      return Collections.singletonList(new VariableLookupItem((PsiVariable)completion).setSubstitutor(substitutor).qualifyIfNeeded(reference));
     }
     if (completion instanceof PsiPackage) {
       return Collections.singletonList(new PackageLookupItem((PsiPackage)completion, reference.getElement()));

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

@@ -8,6 +8,7 @@ import com.intellij.featureStatistics.FeatureUsageTracker;
 import com.intellij.psi.*;
 import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.psi.util.PsiUtil;
+import com.intellij.util.ObjectUtils;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -18,12 +19,13 @@ import java.util.List;
 */
 public class JavaStaticMemberProcessor extends StaticMemberProcessor {
   private final PsiElement myOriginalPosition;
+  private final PsiElement myPosition;
 
   public JavaStaticMemberProcessor(CompletionParameters parameters) {
     super(parameters.getPosition());
     myOriginalPosition = parameters.getOriginalPosition();
-
-    final PsiFile file = parameters.getPosition().getContainingFile();
+    myPosition = parameters.getPosition();
+    final PsiFile file = myPosition.getContainingFile();
     if (file instanceof PsiJavaFile) {
       final PsiImportList importList = ((PsiJavaFile)file).getImportList();
       if (importList != null) {
@@ -60,7 +62,7 @@ public class JavaStaticMemberProcessor extends StaticMemberProcessor {
 
         super.handleInsert(context);
       }
-    });
+    }.qualifyIfNeeded(ObjectUtils.tryCast(myPosition.getParent(), PsiJavaCodeReferenceElement.class)));
   }
 
   private PsiReference createReferenceToMemberName(@NotNull PsiMember member) {

java/java-impl/src/com/intellij/codeInsight/lookup/VariableLookupItem.java

@@ -20,6 +20,7 @@ import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.psi.util.PsiUtil;
 import com.intellij.util.ui.ColorIcon;
 import com.intellij.util.ui.JBUI;
+import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -35,6 +36,7 @@ public class VariableLookupItem extends LookupItem<PsiVariable> implements Typed
   private final Color myColor;
   private final String myTailText;
   private PsiSubstitutor mySubstitutor = PsiSubstitutor.EMPTY;
+  private String myForcedQualifier;
 
   public VariableLookupItem(PsiVariable var) {
     super(var, var.getName());
@@ -46,15 +48,31 @@ public class VariableLookupItem extends LookupItem<PsiVariable> implements Typed
   public VariableLookupItem(PsiField field, boolean shouldImport) {
     super(field, field.getName());
     myHelper = new MemberLookupHelper(field, field.getContainingClass(), shouldImport, false);
-    if (!shouldImport) {
-      for (String s : JavaCompletionUtil.getAllLookupStrings(field)) {
-        setLookupString(s); //todo set the string that will be inserted
-      }
-    }
     myColor = getInitializerColor(field);
     myTailText = getInitializerText(field);
   }
 
+  @ApiStatus.Internal
+  public LookupElement qualifyIfNeeded(@Nullable PsiReference position) {
+    PsiVariable var = getObject();
+    if (var instanceof PsiField && !willBeImported() && shouldQualify((PsiField)var, position)) {
+      boolean isInstanceField = !var.hasModifierProperty(PsiModifier.STATIC);
+      PsiClass aClass = ((PsiField)var).getContainingClass();
+      String className = aClass == null ? null : aClass.getName();
+      if (className != null) {
+        String infix = isInstanceField ? ".this." : ".";
+        myForcedQualifier = className + infix;
+        for (String s : JavaCompletionUtil.getAllLookupStrings(aClass)) {
+          setLookupString(s + infix + var.getName());
+        }
+        if (isInstanceField) {
+          return PrioritizedLookupElement.withExplicitProximity(this, -1);
+        }
+      }
+    }
+    return this;
+  }
+
   @Nullable
   private String getInitializerText(PsiVariable var) {
     if (myColor != null || !var.hasModifierProperty(PsiModifier.FINAL) || !var.hasModifierProperty(PsiModifier.STATIC)) return null;
@@ -124,12 +142,12 @@ public class VariableLookupItem extends LookupItem<PsiVariable> implements Typed
 
   @Override
   public void renderElement(LookupElementPresentation presentation) {
-    boolean qualify = myHelper != null && !myHelper.willBeImported();
+    boolean qualify = myHelper != null && !myHelper.willBeImported() || myForcedQualifier != null;
 
     PsiVariable variable = getObject();
     String name = variable.getName();
     if (qualify && variable instanceof PsiField && ((PsiField)variable).getContainingClass() != null) {
-      name = ((PsiField)variable).getContainingClass().getName() + "." + name;
+      name = (myForcedQualifier != null ? myForcedQualifier : ((PsiField)variable).getContainingClass().getName() + ".") + name;
     }
     presentation.setItemText(name);
 
@@ -259,10 +277,13 @@ public class VariableLookupItem extends LookupItem<PsiVariable> implements Typed
       return true;
     }
 
-    PsiReference reference = context.getFile().findReferenceAt(context.getStartOffset());
-    if (reference instanceof PsiReferenceExpression && !((PsiReferenceExpression)reference).isQualified()) {
-      final PsiVariable target = JavaPsiFacade.getInstance(context.getProject()).getResolveHelper()
-        .resolveReferencedVariable(field.getName(), (PsiElement)reference);
+    return shouldQualify(field, context.getFile().findReferenceAt(context.getTailOffset() - 1));
+  }
+
+  private static boolean shouldQualify(@NotNull PsiField field, @Nullable PsiReference context) {
+    if (context instanceof PsiReferenceExpression && !((PsiReferenceExpression)context).isQualified()) {
+      PsiVariable target = JavaPsiFacade.getInstance(context.getElement().getProject()).getResolveHelper()
+        .resolveReferencedVariable(field.getName(), (PsiElement)context);
       return !field.getManager().areElementsEquivalent(target, CompletionUtil.getOriginalOrSelf(field));
     }
     return false;
@@ -278,7 +299,7 @@ public class VariableLookupItem extends LookupItem<PsiVariable> implements Typed
 
     PsiClass containingClass = field.getContainingClass();
     if (containingClass != null && containingClass.getName() != null) {
-      context.getDocument().insertString(context.getStartOffset(), ".");
+      context.getDocument().insertString(context.getStartOffset(), field.hasModifierProperty(PsiModifier.STATIC) ? "." : ".this.");
       JavaCompletionUtil.insertClassReference(containingClass, file, context.getStartOffset());
       PsiDocumentManager.getInstance(context.getProject()).commitDocument(context.getDocument());
     }

java/java-impl/src/com/intellij/psi/filters/getters/JavaMembersGetter.java

@@ -12,6 +12,7 @@ import com.intellij.psi.tree.IElementType;
 import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.psi.util.PsiUtil;
 import com.intellij.util.Consumer;
+import com.intellij.util.ObjectUtils;
 import com.intellij.util.containers.ContainerUtil;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -133,7 +134,8 @@ public class JavaMembersGetter extends MembersGetter {
       return null;
     }
 
-    return new VariableLookupItem(field, false);
+    return new VariableLookupItem(field, false)
+      .qualifyIfNeeded(ObjectUtils.tryCast(myParameters.getPosition().getParent(), PsiJavaCodeReferenceElement.class));
   }
 
   @Override

java/java-psi-impl/src/com/intellij/codeInsight/completion/scope/CompletionElement.java

@@ -15,6 +15,7 @@
  */
 package com.intellij.codeInsight.completion.scope;
 
+import com.intellij.codeInsight.completion.CompletionUtilCoreImpl;
 import com.intellij.openapi.util.Comparing;
 import com.intellij.openapi.util.Trinity;
 import com.intellij.psi.*;
@@ -70,7 +71,7 @@ public class CompletionElement{
                             myQualifierText);
     }
     if (myElement instanceof PsiVariable) {
-      return "#" + ((PsiVariable)myElement).getName();
+      return CompletionUtilCoreImpl.getOriginalOrSelf((PsiElement)myElement);
     }
 
     return null;

java/java-tests/testData/codeInsight/completion/normal/SameNamedVariableInNestedClasses_after.java

@@ -5,7 +5,7 @@ public class Beda {
         int ffid;
 
         {
-            ffid<caret>
+            Beda.this.ffid<caret>
         }
     }
 }

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

@@ -605,7 +605,7 @@ public class ListUtils {
 
   void testDoubleConstant() throws Throwable {
     configure()
-    assertStringItems("XFOO")
+    assertStringItems("Intf.XFOO", "XFOO")
   }
 
   void testNotOnlyKeywordsInsideSwitch() throws Throwable {
@@ -862,7 +862,10 @@ public class ListUtils {
   }
 
   void testSameNamedVariableInNestedClasses() throws Throwable {
-    doTest()
+    configure()
+    myFixture.assertPreferredCompletionItems 0, "ffid", "Beda.this.ffid"
+    selectItem(myItems[1])
+    checkResult()
   }
 
   void testHonorUnderscoreInPrefix() throws Throwable {