Minor: Generalize visitor type of JetElement.acceptChildren()

compiler/frontend/src/org/jetbrains/kotlin/psi/JetElement.java

@@ -23,7 +23,7 @@ public interface JetElement extends NavigatablePsiElement {
     @NotNull
     JetFile getContainingJetFile();
 
-    <D> void acceptChildren(@NotNull JetTreeVisitor<D> visitor, D data);
+    <D> void acceptChildren(@NotNull JetVisitor<Void, D> visitor, D data);
 
     <R, D> R accept(@NotNull JetVisitor<R, D> visitor, D data);
 }

compiler/frontend/src/org/jetbrains/kotlin/psi/JetElementImpl.java

@@ -62,7 +62,7 @@ public class JetElementImpl extends ASTWrapperPsiElement implements JetElement {
     }
 
     @Override
-    public <D> void acceptChildren(@NotNull JetTreeVisitor<D> visitor, D data) {
+    public <D> void acceptChildren(@NotNull JetVisitor<Void, D> visitor, D data) {
         JetPsiUtil.visitChildren(this, visitor, data);
     }
 

compiler/frontend/src/org/jetbrains/kotlin/psi/JetElementImplStub.java

@@ -70,7 +70,7 @@ public class JetElementImplStub<T extends StubElement> extends StubBasedPsiEleme
     }
 
     @Override
-    public <D> void acceptChildren(@NotNull JetTreeVisitor<D> visitor, D data) {
+    public <D> void acceptChildren(@NotNull JetVisitor<Void, D> visitor, D data) {
         PsiElement child = getFirstChild();
         while (child != null) {
             if (child instanceof JetElement) {

compiler/frontend/src/org/jetbrains/kotlin/psi/JetFile.java

@@ -213,7 +213,7 @@ public class JetFile extends PsiFileBase implements JetDeclarationContainer, Jet
     }
 
     @Override
-    public <D> void acceptChildren(@NotNull JetTreeVisitor<D> visitor, D data) {
+    public <D> void acceptChildren(@NotNull JetVisitor<Void, D> visitor, D data) {
         JetPsiUtil.visitChildren(this, visitor, data);
     }
 

compiler/frontend/src/org/jetbrains/kotlin/psi/JetPsiUtil.java

@@ -59,7 +59,7 @@ public class JetPsiUtil {
         JetExpression getBaseExpression();
     }
 
-    public static <D> void visitChildren(@NotNull JetElement element, @NotNull JetTreeVisitor<D> visitor, D data) {
+    public static <D> void visitChildren(@NotNull JetElement element, @NotNull JetVisitor<Void, D> visitor, D data) {
         PsiElement child = element.getFirstChild();
         while (child != null) {
             if (child instanceof JetElement) {