Simplify function hierarchy in reflection

Get rid of all classes except kotlin.reflect.KFunction, which will be used to
represent all kinds of simple functions.

Lots of changes to test data are related to the fact that KFunction is not an
extension function (as opposed to KMemberFunction and KExtensionFunction who
were) and so a member or an extension function reference now requires all
arguments be passed to it in the parentheses, including receivers. This is
probably temporary until we support calling any function both as a free
function and as an extension. In JS, functions and extension functions are not
interchangeable, so tests on this behavior are removed until this is supported

compiler/testData/diagnostics/tests/callableReference/function/callableRefrenceOnNestedObject.kt

@@ -5,5 +5,5 @@ open class A {
 }
 
 fun test() {
-    A.B.(A::foo)()
-}
+    (A::foo)(A.B)
+}

compiler/testData/diagnostics/tests/callableReference/function/differentPackageClass.kt

@@ -22,7 +22,7 @@ fun main() {
     val y = first.A::bar
     val z = A::baz
 
-    checkSubtype<KMemberFunction0<A, Unit>>(x)
-    checkSubtype<KMemberFunction1<A, Int, Unit>>(y)
-    checkSubtype<KMemberFunction0<A, String>>(z)
+    checkSubtype<KFunction1<A, Unit>>(x)
+    checkSubtype<KFunction2<A, Int, Unit>>(y)
+    checkSubtype<KFunction1<A, String>>(z)
 }

compiler/testData/diagnostics/tests/callableReference/function/differentPackageExtension.kt

@@ -14,7 +14,7 @@ fun A.baz() {}
 
 package other
 
-import kotlin.reflect.KExtensionFunction0
+import kotlin.reflect.KFunction1
 
 import first.A
 import first.foo
@@ -24,5 +24,5 @@ fun main() {
     first.A::<!UNRESOLVED_REFERENCE!>bar<!>
     A::<!UNRESOLVED_REFERENCE!>baz<!>
 
-    checkSubtype<KExtensionFunction0<A, Unit>>(x)
-}
+    checkSubtype<KFunction1<A, Unit>>(x)
+}

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

@@ -8,9 +8,9 @@ class A {
         val y = ::bar
         val z = ::baz
 
-        checkSubtype<KExtensionFunction0<A, Unit>>(x)
-        checkSubtype<KExtensionFunction1<A, Int, Unit>>(y)
-        checkSubtype<KExtensionFunction0<A, String>>(z)
+        checkSubtype<KFunction1<A, Unit>>(x)
+        checkSubtype<KFunction2<A, Int, Unit>>(y)
+        checkSubtype<KFunction1<A, String>>(z)
     }
 }
 

compiler/testData/diagnostics/tests/callableReference/function/extensionFromExtension.kt

@@ -9,9 +9,9 @@ fun A.main() {
     val y = ::bar
     val z = ::baz
 
-    checkSubtype<KExtensionFunction0<A, Unit>>(x)
-    checkSubtype<KExtensionFunction1<A, Int, Unit>>(y)
-    checkSubtype<KExtensionFunction0<A, String>>(z)
+    checkSubtype<KFunction1<A, Unit>>(x)
+    checkSubtype<KFunction2<A, Int, Unit>>(y)
+    checkSubtype<KFunction1<A, String>>(z)
 }
 
 fun A.foo() {}

compiler/testData/diagnostics/tests/callableReference/function/extensionFromExtensionInClass.kt

@@ -10,9 +10,9 @@ class A {
         val y = ::bar
         val z = ::baz
 
-        checkSubtype<KExtensionFunction0<A, Unit>>(x)
-        checkSubtype<KExtensionFunction1<A, Int, Unit>>(y)
-        checkSubtype<KExtensionFunction0<A, String>>(z)
+        checkSubtype<KFunction1<A, Unit>>(x)
+        checkSubtype<KFunction2<A, Int, Unit>>(y)
+        checkSubtype<KFunction1<A, String>>(z)
     }
 }
 

compiler/testData/diagnostics/tests/callableReference/function/extensionFromTopLevel.kt

@@ -13,11 +13,11 @@ fun main() {
     val y = A::bar
     val z = A::baz
 
-    checkSubtype<KExtensionFunction0<A, Unit>>(x)
-    checkSubtype<KExtensionFunction1<A, Int, Unit>>(y)
-    checkSubtype<KExtensionFunction0<A, String>>(z)
+    checkSubtype<KFunction1<A, Unit>>(x)
+    checkSubtype<KFunction2<A, Int, Unit>>(y)
+    checkSubtype<KFunction1<A, String>>(z)
 
-    checkSubtype<KExtensionFunction<A, Unit>>(x)
-    checkSubtype<KExtensionFunction<A, Unit>>(y)
-    checkSubtype<KExtensionFunction<A, String>>(z)
+    checkSubtype<KFunction<Unit>>(x)
+    checkSubtype<KFunction<Unit>>(y)
+    checkSubtype<KFunction<String>>(z)
 }

compiler/testData/diagnostics/tests/callableReference/function/extensionOnNullable.kt

@@ -8,5 +8,5 @@ class A {
 
 fun A?.foo() {}
 
-val f: KMemberFunction0<A, Unit> = A::foo
-val g: KExtensionFunction0<A, Unit> = A?::foo
+val f: KFunction1<A, Unit> = A::foo
+val g: KFunction1<A, Unit> = A?::foo

compiler/testData/diagnostics/tests/callableReference/function/extensionOnNullable.txt

@@ -1,7 +1,7 @@
 package
 
-internal val f: kotlin.reflect.KMemberFunction0<A, kotlin.Unit>
-internal val g: kotlin.reflect.KExtensionFunction0<A, kotlin.Unit>
+internal val f: kotlin.reflect.KFunction1<A, kotlin.Unit>
+internal val g: kotlin.reflect.KFunction1<A, kotlin.Unit>
 internal fun A?.foo(): kotlin.Unit
 
 internal final class A {

compiler/testData/diagnostics/tests/callableReference/function/genericClassFromTopLevel.kt

@@ -1,6 +1,6 @@
 // !CHECK_TYPE
 
-import kotlin.reflect.KMemberFunction0
+import kotlin.reflect.KFunction1
 
 class A<T>(val t: T) {
     fun foo(): T = t
@@ -9,5 +9,5 @@ class A<T>(val t: T) {
 fun bar() {
     val x = A<String>::foo
 
-    checkSubtype<KMemberFunction0<A<String>, String>>(x)
+    checkSubtype<KFunction1<A<String>, String>>(x)
 }

compiler/testData/diagnostics/tests/callableReference/function/innerConstructorFromClass.kt

@@ -1,6 +1,6 @@
 // !CHECK_TYPE
 // !DIAGNOSTICS: -UNUSED_EXPRESSION
-import kotlin.reflect.KMemberFunction0
+import kotlin.reflect.KFunction1
 
 class A {
     inner class Inner
@@ -9,8 +9,8 @@ class A {
         val x = ::Inner
         val y = A::Inner
 
-        checkSubtype<KMemberFunction0<A, A.Inner>>(x)
-        checkSubtype<KMemberFunction0<A, Inner>>(y)
+        checkSubtype<KFunction1<A, A.Inner>>(x)
+        checkSubtype<KFunction1<A, Inner>>(y)
     }
     
     companion object {
@@ -18,7 +18,7 @@ class A {
             ::<!INACCESSIBLE_OUTER_CLASS_EXPRESSION!>Inner<!>
             val y = A::Inner
 
-            checkSubtype<KMemberFunction0<A, A.Inner>>(y)
+            checkSubtype<KFunction1<A, A.Inner>>(y)
         }
     }
 }
@@ -28,6 +28,6 @@ class B {
         ::<!UNRESOLVED_REFERENCE!>Inner<!>
         val y = A::Inner
 
-        checkSubtype<KMemberFunction0<A, A.Inner>>(y)
+        checkSubtype<KFunction1<A, A.Inner>>(y)
     }
-}
+}

compiler/testData/diagnostics/tests/callableReference/function/innerConstructorFromExtension.kt

@@ -1,6 +1,6 @@
 // !CHECK_TYPE
 // !DIAGNOSTICS: -UNUSED_EXPRESSION
-import kotlin.reflect.KMemberFunction0
+import kotlin.reflect.KFunction1
 
 class A {
     inner class Inner
@@ -10,13 +10,13 @@ fun A.main() {
     val x = ::Inner
     val y = A::Inner
 
-    checkSubtype<KMemberFunction0<A, A.Inner>>(x)
-    checkSubtype<KMemberFunction0<A, A.Inner>>(y)
+    checkSubtype<KFunction1<A, A.Inner>>(x)
+    checkSubtype<KFunction1<A, A.Inner>>(y)
 }
 
 fun Int.main() {
     ::<!UNRESOLVED_REFERENCE!>Inner<!>
     val y = A::Inner
 
-    checkSubtype<KMemberFunction0<A, A.Inner>>(y)
-}
+    checkSubtype<KFunction1<A, A.Inner>>(y)
+}

compiler/testData/diagnostics/tests/callableReference/function/innerConstructorFromTopLevel.kt

@@ -1,6 +1,6 @@
 // !CHECK_TYPE
 // !DIAGNOSTICS: -UNUSED_EXPRESSION
-import kotlin.reflect.KMemberFunction0
+import kotlin.reflect.KFunction1
 
 class A {
     inner class Inner
@@ -10,5 +10,5 @@ fun main() {
     ::<!UNRESOLVED_REFERENCE!>Inner<!>
     val y = A::Inner
 
-    checkSubtype<KMemberFunction0<A, A.Inner>>(y)
-}
+    checkSubtype<KFunction1<A, A.Inner>>(y)
+}

compiler/testData/diagnostics/tests/callableReference/function/longQualifiedName.kt

@@ -9,10 +9,10 @@ class D {
 
 // FILE: b.kt
 
-import kotlin.reflect.KMemberFunction0
+import kotlin.reflect.KFunction1
 
 fun main() {
     val x = a.b.c.D::foo
 
-    checkSubtype<KMemberFunction0<a.b.c.D, Int>>(x)
+    checkSubtype<KFunction1<a.b.c.D, Int>>(x)
 }

compiler/testData/diagnostics/tests/callableReference/function/longQualifiedNameGeneric.kt

@@ -9,10 +9,10 @@ class D<E, F> {
 
 // FILE: b.kt
 
-import kotlin.reflect.KMemberFunction2
+import kotlin.reflect.KFunction3
 
 fun main() {
     val x = a.b.c.D<String, Int>::foo
 
-    checkSubtype<KMemberFunction2<a.b.c.D<String, Int>, String, Int, a.b.c.D<String, Int>>>(x)
+    checkSubtype<KFunction3<a.b.c.D<String, Int>, String, Int, a.b.c.D<String, Int>>>(x)
 }

compiler/testData/diagnostics/tests/callableReference/function/memberFromClass.kt

@@ -12,8 +12,8 @@ class A {
         val y = ::bar
         val z = ::baz
 
-        checkSubtype<KMemberFunction0<A, Unit>>(x)
-        checkSubtype<KMemberFunction1<A, Int, Unit>>(y)
-        checkSubtype<KMemberFunction0<A, String>>(z)
+        checkSubtype<KFunction1<A, Unit>>(x)
+        checkSubtype<KFunction2<A, Int, Unit>>(y)
+        checkSubtype<KFunction1<A, String>>(z)
     }
 }

compiler/testData/diagnostics/tests/callableReference/function/memberFromExtension.kt

@@ -13,7 +13,7 @@ fun A.main() {
     val y = ::bar
     val z = ::baz
 
-    checkSubtype<KMemberFunction0<A, Unit>>(x)
-    checkSubtype<KMemberFunction1<A, Int, Unit>>(y)
-    checkSubtype<KMemberFunction0<A, String>>(z)
+    checkSubtype<KFunction1<A, Unit>>(x)
+    checkSubtype<KFunction2<A, Int, Unit>>(y)
+    checkSubtype<KFunction1<A, String>>(z)
 }

compiler/testData/diagnostics/tests/callableReference/function/memberFromExtensionInClass.kt

@@ -14,8 +14,8 @@ class B {
         val y = ::bar
         val z = ::baz
 
-        checkSubtype<KMemberFunction0<A, Unit>>(x)
-        checkSubtype<KMemberFunction1<A, Int, Unit>>(y)
-        checkSubtype<KMemberFunction0<A, String>>(z)
+        checkSubtype<KFunction1<A, Unit>>(x)
+        checkSubtype<KFunction2<A, Int, Unit>>(y)
+        checkSubtype<KFunction1<A, String>>(z)
     }
 }

compiler/testData/diagnostics/tests/callableReference/function/memberFromTopLevel.kt

@@ -13,11 +13,11 @@ fun main() {
     val y = A::bar
     val z = A::baz
 
-    checkSubtype<KMemberFunction0<A, Unit>>(x)
-    checkSubtype<KMemberFunction1<A, Int, Unit>>(y)
-    checkSubtype<KMemberFunction0<A, String>>(z)
+    checkSubtype<KFunction1<A, Unit>>(x)
+    checkSubtype<KFunction2<A, Int, Unit>>(y)
+    checkSubtype<KFunction1<A, String>>(z)
 
-    checkSubtype<KMemberFunction<A, Unit>>(x)
-    checkSubtype<KMemberFunction<A, Unit>>(y)
-    checkSubtype<KMemberFunction<A, String>>(z)
+    checkSubtype<KFunction<Unit>>(x)
+    checkSubtype<KFunction<Unit>>(y)
+    checkSubtype<KFunction<String>>(z)
 }

compiler/testData/diagnostics/tests/callableReference/function/noAmbiguityMemberVsExtension.kt

@@ -1,6 +1,6 @@
 // !CHECK_TYPE
 
-import kotlin.reflect.KMemberFunction0
+import kotlin.reflect.KFunction1
 
 class A {
     fun foo() = 42
@@ -11,5 +11,5 @@ fun A.foo() {}
 fun main() {
     val x = A::foo
 
-    checkSubtype<KMemberFunction0<A, Int>>(x)
+    checkSubtype<KFunction1<A, Int>>(x)
 }

compiler/testData/diagnostics/tests/callableReference/function/noAmbiguityMemberVsTopLevel.kt

@@ -1,6 +1,6 @@
 // !CHECK_TYPE
 
-import kotlin.reflect.KMemberFunction0
+import kotlin.reflect.KFunction1
 
 fun foo() {}
 
@@ -10,6 +10,6 @@ class A {
     fun main() {
         val x = ::foo
 
-        checkSubtype<KMemberFunction0<A, Unit>>(x)
+        checkSubtype<KFunction1<A, Unit>>(x)
     }
 }

compiler/testData/diagnostics/tests/callableReference/function/renameOnImport.kt

@@ -25,6 +25,6 @@ fun main() {
     val z = AA::bazbaz
 
     checkSubtype<KFunction0<Unit>>(x)
-    checkSubtype<KMemberFunction0<AA, Int>>(y)
-    checkSubtype<KExtensionFunction1<AA, String, Unit>>(z)
+    checkSubtype<KFunction1<AA, Int>>(y)
+    checkSubtype<KFunction2<AA, String, Unit>>(z)
 }