deprecating types after colon

compiler/testData/diagnostics/testsWithStdLib/callableReference/function/extensionFromClass.kt

@@ -1,3 +1,5 @@
+// !CHECK_TYPE
+
 import kotlin.reflect.*
 
 class A {
@@ -6,9 +8,9 @@ class A {
         val y = ::bar
         val z = ::baz
 
-        x : KExtensionFunction0<A, Unit>
-        y : KExtensionFunction1<A, Int, Unit>
-        z : KExtensionFunction0<A, String>
+        checkSubtype<KExtensionFunction0<A, Unit>>(x)
+        checkSubtype<KExtensionFunction1<A, Int, Unit>>(y)
+        checkSubtype<KExtensionFunction0<A, String>>(z)
     }
 }