IDEA-98132 Improve type parameter lookup

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

@@ -142,7 +142,9 @@ public class JavaPsiClassReferenceElement extends LookupItem<Object> {
   }
 
   public static void renderClassItem(LookupElementPresentation presentation, LookupItem item, PsiClass psiClass, boolean diamond) {
-    presentation.setIcon(DefaultLookupItemRenderer.getRawIcon(item, presentation.isReal()));
+    if (!(psiClass instanceof PsiTypeParameter)) {
+      presentation.setIcon(DefaultLookupItemRenderer.getRawIcon(item, presentation.isReal()));
+    }
 
     final boolean bold = item.getAttribute(LookupItem.HIGHLIGHTED_ATTR) != null;
     boolean strikeout = JavaElementLookupRenderer.isToStrikeout(item);

java/java-psi-api/src/com/intellij/psi/util/PsiFormatUtil.java

@@ -431,6 +431,20 @@ public class PsiFormatUtil extends PsiFormatUtilBase {
   }
 
   public static String getPackageDisplayName(@NotNull final PsiClass psiClass) {
+    if (psiClass instanceof PsiTypeParameter) {
+      PsiTypeParameterListOwner owner = ((PsiTypeParameter)psiClass).getOwner();
+      String ownerName = null;
+      if (owner instanceof PsiClass) {
+        ownerName = ((PsiClass)owner).getQualifiedName();
+        if (ownerName == null) {
+          ownerName = owner.getName();
+        }
+      } else if (owner instanceof PsiMethod) {
+        ownerName = owner.getName();
+      }
+      return ownerName == null ? "type parameter" : "type parameter of " + ownerName;
+    }
+
     @NonNls String packageName = psiClass.getQualifiedName();
     packageName = packageName == null || packageName.lastIndexOf('.') <= 0 ? "" : packageName.substring(0, packageName.lastIndexOf('.'));
     if (packageName.isEmpty()) {

java/java-tests/testData/codeInsight/completion/normal/TypeParameterItemPresentation.java

@@ -0,0 +1,5 @@
+public class Foo<Param> {
+  <Param2> int goo() {
+    Pa<caret>
+  }
+}

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

@@ -85,6 +85,20 @@ public class NormalCompletionTest extends LightFixtureCompletionTestCase {
 
   public void testSimpleVariable() throws Exception { doTest('\n') }
 
+  public void testTypeParameterItemPresentation() {
+    configure()
+    LookupElementPresentation presentation = renderElement(myItems[0])
+    assert "Param" == presentation.itemText
+    assert presentation.tailText == " (type parameter of Foo)"
+    assert !presentation.typeText
+    assert !presentation.icon
+    assert !presentation.itemTextBold
+
+    presentation = renderElement(myItems[1])
+    assert "Param2" == presentation.itemText
+    assert presentation.tailText == " (type parameter of goo)"
+  }
+
   public void testMethodItemPresentation() {
     configure()
     LookupElementPresentation presentation = renderElement(myItems[0])