java smart completion: prefer all items with exactly expected type, not only classes (IDEA-169490)

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

@@ -298,9 +298,9 @@ public class JavaCompletionSorting {
     private final CompletionParameters myParameters;
     private final CompletionLocation myLocation;
 
-    public PreferDefaultTypeWeigher(ExpectedTypeInfo[] expectedTypes, CompletionParameters parameters) {
+    public PreferDefaultTypeWeigher(@NotNull ExpectedTypeInfo[] expectedTypes, CompletionParameters parameters) {
       super("defaultType");
-      myExpectedTypes = expectedTypes == null ? null : ContainerUtil.map2Array(expectedTypes, ExpectedTypeInfo.class, info -> {
+      myExpectedTypes = ContainerUtil.map2Array(expectedTypes, ExpectedTypeInfo.class, info -> {
         PsiType type = removeClassWildcard(info.getType());
         PsiType defaultType = removeClassWildcard(info.getDefaultType());
         if (type == info.getType() && defaultType == info.getDefaultType()) {
@@ -328,25 +328,16 @@ public class JavaCompletionSorting {
         }
       }
 
-      if (myExpectedTypes == null) return MyResult.normal;
-
       PsiType itemType = JavaCompletionUtil.getLookupElementType(item);
-      if (itemType == null || !itemType.isValid()) return MyResult.normal;
-
-      if (object instanceof PsiClass) {
-        for (final ExpectedTypeInfo info : myExpectedTypes) {
-          if (TypeConversionUtil.erasure(info.getType().getDeepComponentType()).equals(TypeConversionUtil.erasure(itemType))) {
-            return AbstractExpectedTypeSkipper.skips(item, myLocation) ? MyResult.expectedNoSelect : MyResult.exactlyExpected;
-          }
-        }
+      if (isExactlyExpected(item, itemType)) {
+        return AbstractExpectedTypeSkipper.skips(item, myLocation) ? MyResult.expectedNoSelect : MyResult.exactlyExpected;
       }
 
+      if (itemType == null) return MyResult.normal;
+
       for (final ExpectedTypeInfo expectedInfo : myExpectedTypes) {
         final PsiType defaultType =  expectedInfo.getDefaultType();
         final PsiType expectedType = expectedInfo.getType();
-        if (!expectedType.isValid()) {
-          return MyResult.normal;
-        }
 
         if (defaultType != expectedType) {
           if (defaultType.equals(itemType)) {
@@ -365,6 +356,27 @@ public class JavaCompletionSorting {
       return MyResult.normal;
     }
 
+    private boolean isExactlyExpected(@NotNull LookupElement item, @Nullable PsiType itemType) {
+      if (JavaCompletionUtil.SUPER_METHOD_PARAMETERS.get(item) != null) {
+        return true;
+      }
+      if (itemType == null || itemType.equalsToText(CommonClassNames.JAVA_LANG_OBJECT) || hasUnboundTypeArguments(item)) {
+        return false;
+      }
+
+      return ContainerUtil.exists(myExpectedTypes, info -> box(info.getType().getDeepComponentType()).equals(box(itemType)));
+    }
+
+    private static boolean hasUnboundTypeArguments(@NotNull LookupElement item) {
+      JavaMethodCallElement call = item.as(JavaMethodCallElement.CLASS_CONDITION_KEY);
+      return call != null && !call.getInferenceSubstitutor().equals(PsiSubstitutor.EMPTY);
+    }
+
+    private PsiType box(PsiType expectedType) {
+      PsiClassType boxed = expectedType instanceof PsiPrimitiveType ? ((PsiPrimitiveType)expectedType).getBoxedType(myParameters.getPosition()) : null;
+      return boxed != null ? boxed : expectedType;
+    }
+
     private static PsiType removeClassWildcard(PsiType type) {
       if (type instanceof PsiClassType) {
         final PsiClass psiClass = ((PsiClassType)type).resolve();

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

@@ -19,6 +19,7 @@ import com.intellij.codeInsight.lookup.LookupElement;
 import com.intellij.openapi.util.registry.Registry;
 import com.intellij.psi.PsiMethod;
 import com.intellij.psi.PsiType;
+import one.util.streamex.StreamEx;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -52,15 +53,13 @@ public class JavaMethodMergingContributor extends CompletionContributor {
           return AutoCompletionDecision.SHOW_LOOKUP;
         }
 
-        final PsiMethod method = (PsiMethod)o;
-        final JavaChainLookupElement chain = item.as(JavaChainLookupElement.CLASS_CONDITION_KEY);
-        final String name = method.getName() + "#" + (chain == null ? "" : chain.getQualifier().getLookupString());
+        String name = joinLookupStrings(item);
         if (commonName != null && !commonName.equals(name)) {
           return AutoCompletionDecision.SHOW_LOOKUP;
         }
 
         commonName = name;
-        allMethods.add(method);
+        allMethods.add((PsiMethod)o);
       }
 
       for (LookupElement item : items) {
@@ -73,6 +72,10 @@ public class JavaMethodMergingContributor extends CompletionContributor {
     return super.handleAutoCompletionPossibility(context);
   }
 
+  public static String joinLookupStrings(LookupElement item) {
+    return StreamEx.of(item.getAllLookupStrings()).sorted().joining("#");
+  }
+
   public static LookupElement findBestOverload(LookupElement[] items) {
     LookupElement best = items[0];
     for (int i = 1; i < items.length; i++) {

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

@@ -0,0 +1,12 @@
+class Map {
+  static class Builder {}
+  static Builder builder() {} 
+}
+class BiMap extends Map {
+  static class Builder extends Map.Builder {}
+  static Builder builder() {}
+}
+
+class Usage {
+  Map.Builder b = bui<caret>
+}

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

@@ -33,7 +33,7 @@ class SmartTypeCompletionOrderingTest extends CompletionSortingTestCase {
   }
 
   void testJComponentAdd() throws Throwable {
-    checkPreferredItems(0, "name", "b", "fooBean239", "foo", "this")
+    checkPreferredItems(0, "name", "b", "fooBean239", "foo")
   }
 
   void testJComponentAddNew() throws Throwable {
@@ -323,7 +323,7 @@ class SmartTypeCompletionOrderingTest extends CompletionSortingTestCase {
   }
 
   void testPreferLocalOverThis() {
-    checkPreferredItems 0, 'value', 'this', 'hashCode'
+    checkPreferredItems 0, 'value', 'hashCode', 'this'
   }
 
   void testGetLogger() {
@@ -339,7 +339,7 @@ class SmartTypeCompletionOrderingTest extends CompletionSortingTestCase {
   }
 
   void testPreferLocalWildcardClassOverObject() {
-    checkPreferredItems 0, 'type', 'Object.class'
+    checkPreferredItems 0, 'type', 'forName', 'forName', 'Object.class'
   }
 
   void testPreferStringsInStringConcatenation() {
@@ -361,6 +361,13 @@ class SmartTypeCompletionOrderingTest extends CompletionSortingTestCase {
     assert lookup.items.size() == 2
   }
 
+  void testPreferGlobalMembersReturningExpectedType() {
+    configureNoCompletion(getTestName(false) + ".java")
+    def items = myFixture.complete(CompletionType.SMART, 2)
+    assert LookupElementPresentation.renderElement(items[0]).itemText == 'Map.builder'
+    assert LookupElementPresentation.renderElement(items[1]).itemText == 'BiMap.builder'
+  }
+
   @Override
   protected String getBasePath() {
     return JavaTestUtil.getRelativeJavaTestDataPath() + BASE_PATH

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

@@ -830,7 +830,7 @@ public class SmartTypeCompletionTest extends LightFixtureCompletionTestCase {
   }
   public void testNoClassLiteral() throws Exception {
     doActionTest();
-    assertStringItems("Object.class", "getClass", "forName", "forName");
+    assertStringItems("forName", "forName", "Object.class", "getClass");
   }
 
   public void testClassLiteralInAnno2() throws Throwable {

plugins/groovy/src/org/jetbrains/plugins/groovy/lang/completion/GrMethodMergingContributor.java

@@ -51,9 +51,8 @@ public class GrMethodMergingContributor extends CompletionContributor {
           return AutoCompletionDecision.SHOW_LOOKUP;
         }
 
-        final PsiMethod method = (PsiMethod)o;
-        final JavaChainLookupElement chain = item.as(JavaChainLookupElement.CLASS_CONDITION_KEY);
-        final String name = method.getName() + "#" + (chain == null ? "" : chain.getQualifier().getLookupString());
+        PsiMethod method = (PsiMethod)o;
+        String name = JavaMethodMergingContributor.joinLookupStrings(item);
 
         if (commonName != null && !commonName.equals(name)) {
           return AutoCompletionDecision.SHOW_LOOKUP;