don't suggest expression-keyword-named members in java completion (EA-90531, IDEA-CR-20701)

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

@@ -21,7 +21,7 @@ import com.intellij.codeInsight.lookup.VariableLookupItem;
 import com.intellij.featureStatistics.FeatureUsageTracker;
 import com.intellij.psi.*;
 import com.intellij.psi.util.PsiTreeUtil;
-import com.intellij.util.IncorrectOperationException;
+import com.intellij.psi.util.PsiUtil;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -53,6 +53,10 @@ public class JavaStaticMemberProcessor extends StaticMemberProcessor {
   protected LookupElement createLookupElement(@NotNull PsiMember member, @NotNull final PsiClass containingClass, boolean shouldImport) {
     shouldImport |= myOriginalPosition != null && PsiTreeUtil.isAncestor(containingClass, myOriginalPosition, false);
 
+    if (!PsiNameHelper.getInstance(member.getProject()).isIdentifier(member.getName(), PsiUtil.getLanguageLevel(getPosition()))) {
+      return null;
+    }
+
     PsiReference ref = createReferenceToMemberName(member);
     if (ref == null) return null;
 
@@ -74,13 +78,8 @@ public class JavaStaticMemberProcessor extends StaticMemberProcessor {
   }
 
   private PsiReference createReferenceToMemberName(@NotNull PsiMember member) {
-    try {
-      String exprText = member.getName() + (member instanceof PsiMethod ? "()" : "");
-      return JavaPsiFacade.getElementFactory(member.getProject()).createExpressionFromText(exprText, myOriginalPosition).findReferenceAt(0);
-    }
-    catch (IncorrectOperationException e) {
-      return null;
-    }
+    String exprText = member.getName() + (member instanceof PsiMethod ? "()" : "");
+    return JavaPsiFacade.getElementFactory(member.getProject()).createExpressionFromText(exprText, myOriginalPosition).findReferenceAt(0);
   }
 
   @Override

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

@@ -132,6 +132,10 @@ public abstract class StaticMemberProcessor {
     return member.hasModifierProperty(PsiModifier.STATIC) && isAccessible(member) && !StaticImportMemberFix.isExcluded(member);
   }
 
+  public PsiElement getPosition() {
+    return myPosition;
+  }
+
   protected boolean isAccessible(PsiMember member) {
     return myResolveHelper.isAccessible(member, myPosition, null);
   }

plugins/groovy/test/org/jetbrains/plugins/groovy/completion/JavaWithGroovyCompletionTest.groovy

@@ -15,7 +15,8 @@
  */
 package org.jetbrains.plugins.groovy.completion
 
-import com.intellij.codeInsight.completion.CompletionType;
+import com.intellij.codeInsight.completion.CompletionType
+import com.intellij.psi.PsiMethod;
 
 /**
  * @author peter
@@ -34,4 +35,15 @@ class Foo {
     assert !(myFixture.lookupElementStrings.contains('const'))
     assert !(myFixture.lookupElementStrings.contains('continue'))
   }
+
+  void "test using java expression keywords in member names"() {
+    myFixture.addFileToProject 'a.groovy', '''
+class Foo {
+  static void "this"() {}
+}
+'''
+    myFixture.configureByText 'a.java', 'class Bar {{ this<caret> }}'
+    myFixture.complete(CompletionType.BASIC, 2)
+    assert !myFixture.lookupElements.find { it.lookupString == 'this' && it.object instanceof PsiMethod }
+  }
 }