IDEA-173437 Completion suggestion is bad for ObjectUtils.tryCast

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

@@ -39,6 +39,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
@@ -329,6 +330,8 @@ public class JavaCompletionSorting {
         }
       }
 
+      if (returnsUnboundType(item)) return MyResult.normal;
+
       PsiType itemType = JavaCompletionUtil.getLookupElementType(item);
       if (isExactlyExpected(item, itemType)) {
         return AbstractExpectedTypeSkipper.skips(item, myLocation) ? MyResult.expectedNoSelect : MyResult.exactlyExpected;
@@ -361,16 +364,25 @@ public class JavaCompletionSorting {
       if (JavaCompletionUtil.SUPER_METHOD_PARAMETERS.get(item) != null) {
         return true;
       }
-      if (itemType == null || itemType.equalsToText(CommonClassNames.JAVA_LANG_OBJECT) || hasUnboundTypeArguments(item)) {
+      if (itemType == null || itemType.equalsToText(CommonClassNames.JAVA_LANG_OBJECT)) {
         return false;
       }
 
       return ContainerUtil.exists(myExpectedTypes, info -> box(info.getType().getDeepComponentType()).equals(box(itemType)));
     }
 
-    private static boolean hasUnboundTypeArguments(@NotNull LookupElement item) {
+    private boolean returnsUnboundType(@NotNull LookupElement item) {
       JavaMethodCallElement call = item.as(JavaMethodCallElement.CLASS_CONDITION_KEY);
-      return call != null && !call.getInferenceSubstitutor().equals(PsiSubstitutor.EMPTY);
+      if (call != null && !call.getInferenceSubstitutor().equals(PsiSubstitutor.EMPTY)) {
+        PsiType callType = TypeConversionUtil.erasure(call.getSubstitutor().substitute(call.getObject().getReturnType()));
+        return callType == null || Arrays.stream(myExpectedTypes).noneMatch(i -> canBeExpected(callType, i));
+      }
+      return false;
+    }
+
+    private static boolean canBeExpected(PsiType callType, ExpectedTypeInfo info) {
+      PsiType expectedType = TypeConversionUtil.erasure(info.getType());
+      return expectedType != null && TypeConversionUtil.isAssignable(expectedType, callType);
     }
 
     private PsiType box(PsiType expectedType) {

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

@@ -0,0 +1,11 @@
+public class Foo  {
+
+    void foo(Object o) {
+        String s = Util.tryCast(o, <caret>);
+    }
+
+}
+
+class Util {
+    static <T> T tryCast(Object obj, Class<T> clazz) {}
+}

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

@@ -211,7 +211,7 @@ public class SecondSmartTypeCompletionTest extends LightFixtureCompletionTestCas
 
   public void testGlobalFactoryMethods() {
     configure();
-    assertStringItems("Constants.SUBSTRING", "createExpected", "createSubGeneric", "createSubRaw", "createSubString");
+    assertStringItems("createExpected", "Constants.SUBSTRING", "createSubGeneric", "createSubRaw", "createSubString");
   }
 
   public void testEmptyMapPresentation() {

java/java-tests/testSrc/com/intellij/java/codeInsight/completion/SmartType18CompletionTest.java

@@ -249,4 +249,10 @@ public void testConvertToObjectStream() {
     configureByTestName();
     myFixture.assertPreferredCompletionItems(0, "TimeUnit.DAYS");
   }
+
+  public void testFreeGenericsAfterClassLiteral() {
+    configureByTestName();
+    myFixture.assertPreferredCompletionItems(0, "String.class", "tryCast");
+  }
+
 }

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

@@ -1268,4 +1268,10 @@ public class SmartTypeCompletionTest extends LightFixtureCompletionTestCase {
     myFixture.type('\t');
     checkResultByTestName();
   }
+
+  public void testFreeGenericsAfterClassLiteral() {
+    configureByTestName();
+    myFixture.assertPreferredCompletionItems(0, "String.class", "tryCast");
+  }
+
 }