show shortcuts for overloads switching in parameter info popup

java/java-impl/src/com/intellij/codeInsight/hint/api/impls/MethodParameterInfoHandler.java

@@ -693,4 +693,9 @@ public class MethodParameterInfoHandler implements ParameterInfoHandlerWithTabAc
       updateMethodPresentation((PsiMethod)p, null, context);
     }
   }
+
+  @Override
+  public boolean supportsOverloadSwitching() {
+    return CodeInsightSettings.getInstance().SHOW_PARAMETER_NAME_HINTS_ON_COMPLETION;
+  }
 }

platform/lang-api/src/com/intellij/lang/parameterInfo/ParameterInfoHandler.java

@@ -46,5 +46,6 @@ public interface ParameterInfoHandler <ParameterOwner, ParameterType> {
   @Nullable String getParameterCloseChars();
   boolean tracksParameterIndex();
 
+  default boolean supportsOverloadSwitching() { return false; }
   default void dispose() {}
 }

platform/lang-impl/src/com/intellij/codeInsight/hint/ParameterInfoComponent.java

@@ -17,14 +17,17 @@
 package com.intellij.codeInsight.hint;
 
 import com.google.common.collect.ImmutableMap;
+import com.intellij.codeInsight.CodeInsightBundle;
 import com.intellij.lang.parameterInfo.ParameterInfoHandler;
 import com.intellij.lang.parameterInfo.ParameterInfoUIContextEx;
 import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.editor.Editor;
+import com.intellij.openapi.util.SystemInfo;
 import com.intellij.openapi.util.TextRange;
 import com.intellij.psi.PsiElement;
 import com.intellij.ui.*;
 import com.intellij.util.Function;
+import com.intellij.util.ui.JBEmptyBorder;
 import com.intellij.util.ui.UIUtil;
 import com.intellij.util.ui.accessibility.AccessibleContextUtil;
 import com.intellij.xml.util.XmlStringUtil;
@@ -48,6 +51,7 @@ public class ParameterInfoComponent extends JPanel {
   @NotNull private final ParameterInfoHandler myHandler;
 
   private final OneElementComponent[] myPanels;
+  private final JLabel myShortcutLabel;
 
   private final Font NORMAL_FONT;
   private final Font BOLD_FONT;
@@ -123,6 +127,13 @@ public class ParameterInfoComponent extends JPanel {
     pane.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
     add(pane, BorderLayout.CENTER);
 
+    myShortcutLabel = new JLabel(CodeInsightBundle.message("parameter.info.switch.overload.shortcuts"));
+    myShortcutLabel.setForeground(new JBColor(0x787878, 0x787878));
+    Font labelFont = UIUtil.getLabelFont();
+    myShortcutLabel.setFont(labelFont.deriveFont(labelFont.getSize2D() - (SystemInfo.isWindows ? 1 : 2)));
+    myShortcutLabel.setBorder(new JBEmptyBorder(3, 0, 0, 0));
+    add(myShortcutLabel, BorderLayout.SOUTH);
+
     myCurrentParameterIndex = -1;
   }
 
@@ -255,6 +266,8 @@ public class ParameterInfoComponent extends JPanel {
       }
     }
 
+    myShortcutLabel.setVisible(!singleParameterInfo && myObjects.length > 1 && myHandler.supportsOverloadSwitching());
+
     invalidate();
     validate();
     repaint();

platform/platform-resources-en/src/messages/CodeInsightBundle.properties

@@ -557,4 +557,6 @@ block.comment.intersects.existing.comment=Selected region intersects existing co
 block.comment.wrapping.suffix=Selected region contains block comment suffix
 block.comment.nested.comment=Selected region contained block {0, choice, 1#comment|2#comments},\nsurrounding ranges were commented.
 
-intention.unroll.loop.family=Unroll loop
+intention.unroll.loop.family=Unroll loop
+
+parameter.info.switch.overload.shortcuts=Switch with \u2191 or \u2193