IDEA-119416 Smart type completion proposes nothing in String concatenation expressions

java/java-impl/src/com/intellij/codeInsight/ExpectedTypesProvider.java

@@ -666,7 +666,7 @@ public class ExpectedTypesProvider {
       }
       else if (i == JavaTokenType.PLUS) {
         if (anotherType == null || anotherType.equalsToText(CommonClassNames.JAVA_LANG_STRING)) {
-          myResult = ExpectedTypeInfo.EMPTY_ARRAY;
+          myResult = new ExpectedTypeInfo[]{createInfoImpl(PsiType.getJavaLangObject(expr.getManager(), expr.getResolveScope()), ExpectedTypeInfo.TYPE_OR_SUBTYPE, anotherType, TailType.NONE)};
         }
         else if (PsiType.DOUBLE.isAssignableFrom(anotherType)) {
           myResult = new ExpectedTypeInfo[]{createInfoImpl(PsiType.DOUBLE, ExpectedTypeInfo.TYPE_OR_SUBTYPE, anotherType, TailType.NONE)};

java/java-tests/testData/codeInsight/completion/smartType/EverythingInStringConcatenation-out.java

@@ -0,0 +1,8 @@
+public class Test {
+
+  {
+    int abcdef = 2;
+    System.out.println("" + abcdef<caret>);
+  }
+
+}

java/java-tests/testData/codeInsight/completion/smartType/EverythingInStringConcatenation.java

@@ -0,0 +1,8 @@
+public class Test {
+
+  {
+    int abcdef = 2;
+    System.out.println("" + abc<caret>);
+  }
+
+}

java/java-tests/testData/codeInsight/completion/smartTypeSorting/PreferStringsInStringConcatenation.java

@@ -0,0 +1,6 @@
+class Foo {
+
+  {
+    System.out.println("" + <caret>);
+  }
+}

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

@@ -321,6 +321,10 @@ public class SmartTypeCompletionOrderingTest extends CompletionSortingTestCase {
     checkPreferredItems 0, 'type', 'Object.class'
   }
 
+  public void testPreferStringsInStringConcatenation() {
+    checkPreferredItems 0, 'toString'
+  }
+
   @Override
   protected String getBasePath() {
     return JavaTestUtil.getRelativeJavaTestDataPath() + BASE_PATH;

java/java-tests/testSrc/com/intellij/codeInsight/completion/SmartTypeCompletionTest.java

@@ -1020,6 +1020,7 @@ public class SmartTypeCompletionTest extends LightFixtureCompletionTestCase {
   public void testArrayInitializerBeforeVarargs() throws Throwable { doTest(); }
   public void testDuplicateMembersFromSuperClass() throws Throwable { doTest(); }
   public void testInnerAfterNew() throws Throwable { doTest(); }
+  public void testEverythingInStringConcatenation() throws Throwable { doTest(); }
 
   public void testMemberImportStatically() {
     configureByTestName();