remember completion method statistics per qualifier type (alas, undoing IDEA-87104)

otherwise methods from base classes get preferred over more relevant ones

example: Object methods like equals/getClass would be preselected when invoking a completion in a just created class, instead of its own methods

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

@@ -48,8 +48,6 @@ public class JavaCompletionStatistician extends CompletionStatistician{
     LookupItem item = element.as(LookupItem.CLASS_CONDITION_KEY);
     if (item == null) return null;
 
-    PsiType qualifierType = JavaCompletionUtil.getQualifierType(item);
-
     if (o instanceof PsiMember) {
       final ExpectedTypeInfo[] infos = JavaCompletionUtil.EXPECTED_TYPES.getValue(location);
       final ExpectedTypeInfo firstInfo = infos != null && infos.length > 0 ? infos[0] : null;
@@ -62,7 +60,9 @@ public class JavaCompletionStatistician extends CompletionStatistician{
       PsiClass containingClass = ((PsiMember)o).getContainingClass();
       if (containingClass != null) {
         String expectedName = firstInfo instanceof ExpectedTypeInfoImpl ? ((ExpectedTypeInfoImpl)firstInfo).getExpectedName() : null;
-        String contextPrefix = expectedName == null ? "" : "expectedName=" + expectedName + "###";
+        PsiType qualifierType = JavaCompletionUtil.getQualifierType(item);
+        String contextPrefix = (qualifierType == null ? "" : JavaStatisticsManager.getMemberUseKey1(qualifierType) + "###") +
+                               (expectedName == null ? "" : "expectedName=" + expectedName + "###");
 
         if (o instanceof PsiMethod) {
           String memberValue = JavaStatisticsManager.getMemberUseKey2(RecursionWeigher.findDeepestSuper((PsiMethod)o));
@@ -73,8 +73,6 @@ public class JavaCompletionStatistician extends CompletionStatistician{
       }
     }
 
-    if (qualifierType != null) return StatisticsInfo.EMPTY;
-
     return null;
   }
 

java/java-tests/testData/codeInsight/completion/normalSorting/MethodStatisticsPerQualifierType.java

@@ -0,0 +1,8 @@
+public class Usage<T extends Usage<T>> {
+  void foo(T t) {
+    "".<caret>
+  }
+
+  void someMethod() {}
+
+}

java/java-tests/testData/codeInsight/completion/normalSorting/SameStatsForDifferentQualifiersJComponent.java

@@ -1,9 +0,0 @@
-import javax.swing.*;
-
-public class MyFirstTestClassFoo {
-
-  void foo(JComponent c) {
-    c.getCom<caret>x
-  }
-
-}

java/java-tests/testData/codeInsight/completion/normalSorting/SameStatsForDifferentQualifiersJLabel.java

@@ -1,9 +0,0 @@
-import javax.swing.*;
-
-public class MyFirstTestClassFoo {
-
-  void foo(JLabel l) {
-    l.getCompo<caret>x
-  }
-
-}

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

@@ -23,7 +23,6 @@ import com.intellij.codeInsight.lookup.LookupElementPresentation
 import com.intellij.codeInsight.lookup.impl.LookupImpl
 import com.intellij.codeInsight.template.impl.LiveTemplateCompletionContributor
 import com.intellij.ide.ui.UISettings
-import com.intellij.openapi.fileEditor.FileDocumentManager
 import com.intellij.psi.PsiClass
 import com.intellij.psi.PsiField
 import com.intellij.psi.PsiMethod
@@ -172,32 +171,6 @@ class NormalCompletionOrderingTest extends CompletionSortingTestCase {
     assertPreferredItems(0, "FooBee", "FooBar")
   }
 
-  void testSameStatsForDifferentQualifiers() throws Throwable {
-    invokeCompletion("SameStatsForDifferentQualifiersJLabel.java")
-    assertPreferredItems(0, "getComponent")
-    incUseCount(getLookup(), myFixture.lookupElementStrings.indexOf('getComponents'))
-    FileDocumentManager.instance.saveAllDocuments()
-
-    invokeCompletion("SameStatsForDifferentQualifiersJLabel.java")
-    assertPreferredItems(0, "getComponents", "getComponent")
-
-    invokeCompletion("SameStatsForDifferentQualifiersJComponent.java")
-    assertPreferredItems(0, "getComponents", "getComponent")
-  }
-
-  void testSameStatsForDifferentQualifiers2() throws Throwable {
-    invokeCompletion("SameStatsForDifferentQualifiersJComponent.java")
-    assertPreferredItems(0, "getComponent")
-    incUseCount(getLookup(), myFixture.lookupElementStrings.indexOf('getComponents'))
-    FileDocumentManager.instance.saveAllDocuments()
-
-    invokeCompletion("SameStatsForDifferentQualifiersJComponent.java")
-    assertPreferredItems(0, "getComponents", "getComponent")
-
-    invokeCompletion("SameStatsForDifferentQualifiersJLabel.java")
-    assertPreferredItems(0, "getComponents", "getComponent")
-  }
-
   void testDispreferFinalize() throws Throwable {
     checkPreferredItems(0, "final", "finalize")
   }
@@ -732,4 +705,14 @@ class ContainerUtil extends ContainerUtilRt {
     assert LookupElementPresentation.renderElement(myFixture.lookupElements[1]).tailText.contains('pack2')
   }
 
+  void testMethodStatisticsPerQualifierType() {
+    checkPreferredItems 0, 'charAt'
+    myFixture.type('eq\n);\n')
+    assert myFixture.editor.document.text.contains('equals();\n')
+
+    myFixture.type('this.')
+    myFixture.completeBasic()
+    assertPreferredItems 0, 'someMethod'
+  }
+
 }