FirRenderer: get rid of direct Visitor usages

compiler/fir/tree/src/org/jetbrains/kotlin/fir/Utils.kt

@@ -83,8 +83,8 @@ val FirContextReceiver.labelName: Name? get() = customLabelName ?: labelNameFrom
 fun FirElement.renderWithType(mode: FirRenderer.RenderMode = FirRenderer.RenderMode.Normal): String = buildString {
     append(this@renderWithType)
     append(": ")
-    this@renderWithType.accept(FirRenderer(this, mode).Visitor())
+    FirRenderer(this, mode).renderElementAsString(this@renderWithType)
 }
 
 fun FirElement.render(mode: FirRenderer.RenderMode = FirRenderer.RenderMode.Normal): String =
-    buildString { this@render.accept(FirRenderer(this, mode).Visitor()) }
+    FirRenderer(mode = mode).renderElementAsString(this)

compiler/fir/tree/src/org/jetbrains/kotlin/fir/renderer/FirPrinter.kt

@@ -46,4 +46,8 @@ open class FirPrinter(builder: StringBuilder) {
         popIndent()
         println(rightBrace)
     }
+
+    override fun toString(): String {
+        return printer.toString()
+    }
 }

compiler/fir/tree/src/org/jetbrains/kotlin/fir/renderer/FirRenderer.kt

@@ -40,7 +40,28 @@ open class FirRenderer private constructor(
     components: FirComponentsImpl
 ) : FirPrinter(builder) {
 
-    constructor(builder: StringBuilder, mode: RenderMode = RenderMode.Normal) : this(builder, mode, FirComponentsImpl())
+    companion object {
+        private val visibilitiesToRenderEffectiveSet = setOf(
+            Visibilities.Private, Visibilities.PrivateToThis, Visibilities.Internal,
+            Visibilities.Protected, Visibilities.Public, Visibilities.Local
+        )
+    }
+
+    constructor(builder: StringBuilder = StringBuilder(), mode: RenderMode = RenderMode.Normal) : this(builder, mode, FirComponentsImpl())
+
+    fun renderElementAsString(element: FirElement): String {
+        element.accept(visitor)
+        return toString()
+    }
+
+    fun renderAsCallableDeclarationString(callableDeclaration: FirCallableDeclaration): String {
+        visitor.visitCallableDeclaration(callableDeclaration)
+        return toString()
+    }
+
+    fun renderMemberDeclarationClass(firClass: FirClass) {
+        visitor.visitMemberDeclaration(firClass)
+    }
 
     private class FirComponentsImpl : FirRendererComponents {
         override var annotationRenderer: FirAnnotationRenderer? = null
@@ -54,13 +75,6 @@ open class FirRenderer private constructor(
         override lateinit var printer: FirPrinter
     }
 
-    companion object {
-        private val visibilitiesToRenderEffectiveSet = setOf(
-            Visibilities.Private, Visibilities.PrivateToThis, Visibilities.Internal,
-            Visibilities.Protected, Visibilities.Public, Visibilities.Local
-        )
-    }
-
     data class RenderMode(
         val renderCallArguments: Boolean,
         val renderCallableFqNames: Boolean,
@@ -334,7 +348,7 @@ open class FirRenderer private constructor(
         rValue.accept(visitor)
     }
 
-    inner class Visitor : FirVisitorVoid() {
+    inner class Visitor internal constructor() : FirVisitorVoid() {
 
         override fun visitElement(element: FirElement) {
             element.acceptChildren(this)