Descriptor Renderer: Add parentheses around receiver type if it's non-nullable function type

#KT-8188 Fixed

compiler/testData/diagnostics/tests/ShiftFunctionTypes.txt

@@ -17,7 +17,7 @@ internal abstract class XXX {
     internal abstract val a15: kotlin.Int?.(kotlin.Int) -> kotlin.Int
     internal abstract val a152: kotlin.Int?.(kotlin.Int) -> kotlin.Int
     internal abstract val a16: (kotlin.Int) -> (kotlin.Int) -> kotlin.Int
-    internal abstract val a17: (kotlin.Int) -> kotlin.Int.(kotlin.Int) -> kotlin.Int
+    internal abstract val a17: ((kotlin.Int) -> kotlin.Int).(kotlin.Int) -> kotlin.Int
     internal abstract val a18: (kotlin.Int) -> (kotlin.Int) -> kotlin.Int
     internal abstract val a19: ((kotlin.Int) -> kotlin.Int) -> kotlin.Int
     internal abstract val a2: n.B
@@ -42,7 +42,7 @@ internal abstract class YYY {
     internal abstract val a15: kotlin.Int?.(kotlin.Int) -> kotlin.Int
     internal abstract val a152: kotlin.Int?.(kotlin.Int) -> kotlin.Int
     internal abstract val a16: (kotlin.Int) -> (kotlin.Int) -> kotlin.Int
-    internal abstract val a17: (kotlin.Int) -> kotlin.Int.(kotlin.Int) -> kotlin.Int
+    internal abstract val a17: ((kotlin.Int) -> kotlin.Int).(kotlin.Int) -> kotlin.Int
     internal abstract val a18: (kotlin.Int) -> (kotlin.Int) -> kotlin.Int
     internal abstract val a19: ((kotlin.Int) -> kotlin.Int) -> kotlin.Int
     internal abstract val a7: (A) -> n.B

compiler/testData/diagnostics/tests/functionLiterals/DeprecatedSyntax.txt

@@ -12,7 +12,7 @@ internal val parenthesizedParameters2: (???) -> kotlin.Unit
 internal val receiver: kotlin.Int.() -> kotlin.Unit
 internal val receiverAndReturnType: kotlin.Int.() -> kotlin.Int
 internal val receiverAndReturnTypeWithParameter: kotlin.Int.(kotlin.Int) -> kotlin.Int
-internal val receiverWithFunctionType: (kotlin.Int) -> kotlin.Int.() -> kotlin.Unit
+internal val receiverWithFunctionType: ((kotlin.Int) -> kotlin.Int).() -> kotlin.Unit
 internal val receiverWithParameter: kotlin.Int.(???) -> kotlin.Unit
 internal val returnType: () -> kotlin.Int
 internal val returnTypeWithParameter: (kotlin.Int) -> kotlin.Int

compiler/testData/renderer/FunctionTypes.kt

@@ -19,6 +19,9 @@ var v10: GF<Any>
 class GEF<A, B>: @extension Function1<A, B>
 var v11: GEF<Any, Any>
 
+var v12: (() -> Unit).() -> Unit
+var v13: (() -> Unit)?.() -> Unit
+
 //internal var v1: () -> kotlin.Unit defined in root package
 //internal var v2: (kotlin.Int) -> kotlin.Int defined in root package
 //internal var v3: (kotlin.Int, kotlin.String) -> kotlin.String defined in root package
@@ -42,3 +45,5 @@ var v11: GEF<Any, Any>
 //<A> defined in GEF
 //<B> defined in GEF
 //internal var v11: GEF<kotlin.Any, kotlin.Any> defined in root package
+//internal var v12: (() -> kotlin.Unit).() -> kotlin.Unit defined in root package
+//internal var v13: (() -> kotlin.Unit)?.() -> kotlin.Unit defined in root package

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

@@ -288,7 +288,14 @@ internal class DescriptorRendererImpl(
 
             val receiverType = KotlinBuiltIns.getReceiverType(type)
             if (receiverType != null) {
+                val surroundReceiver = shouldRenderAsPrettyFunctionType(receiverType) && !receiverType.isMarkedNullable()
+                if (surroundReceiver) {
+                    append("(")
+                }
                 append(renderNormalizedType(receiverType))
+                if (surroundReceiver) {
+                    append(")")
+                }
                 append(".")
             }