No parameter names in types for error messages

core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRenderer.kt

@@ -193,6 +193,7 @@ interface DescriptorRendererOptions {
     var renderConstructorKeyword: Boolean
     var renderUnabbreviatedType: Boolean
     var includeAdditionalModifiers: Boolean
+    var parameterNamesInFunctionalTypes: Boolean
 }
 
 object ExcludedTypeAnnotations {

core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRendererImpl.kt

@@ -310,16 +310,16 @@ internal class DescriptorRendererImpl(
 
         append("(")
         val parameterTypes = getValueParameterTypesFromFunctionType(type)
-        val parameterNames = type.getParameterNamesFromFunctionType() ?: parameterTypes.map { SpecialNames.NO_NAME_PROVIDED }
-        assert(parameterNames.size == parameterTypes.size) { "Number of names does not match number of types for $type"}
+        val parameterNames = if (parameterNamesInFunctionalTypes) type.getParameterNamesFromFunctionType() else null
+        assert(parameterNames == null || parameterNames.size == parameterTypes.size) { "Number of names does not match number of types for $type"}
 
         for (index in parameterTypes.indices) {
             val typeProjection = parameterTypes[index]
-            val name = parameterNames[index]
+            val name = parameterNames?.get(index)
 
             if (index > 0) append(", ")
 
-            if (!name.isSpecial) {
+            if (name != null && !name.isSpecial) {
                 append(renderName(name))
                 append(": ")
             }

core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRendererOptionsImpl.kt

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.renderer
 
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.types.KotlinType
+import java.lang.IllegalStateException
 import java.lang.reflect.Modifier
 import kotlin.jvm.internal.PropertyReference1Impl
 import kotlin.properties.Delegates
@@ -103,4 +104,6 @@ internal class DescriptorRendererOptionsImpl : DescriptorRendererOptions {
     override var renderUnabbreviatedType: Boolean by property(true)
 
     override var includeAdditionalModifiers: Boolean by property(true)
+
+    override var parameterNamesInFunctionalTypes: Boolean by property(true)
 }