Allow delegating val properties to out-projected MutableMap

Change generic signature of MutableMap.getValue, use 'out @Exact V' and `V1: V` types instead of single `in V`.
Fix affected IR generation tests.

#KT-18789 Fixed

compiler/testData/ir/irText/declarations/classLevelProperties.txt

@@ -113,8 +113,9 @@ FILE /classLevelProperties.kt
         $this: VALUE_PARAMETER this@C: C
         BLOCK_BODY
           RETURN type=kotlin.Nothing from='<get-test8>(): Int'
-            CALL 'getValue(Any?, KProperty<*>) on MutableMap<in String, in Int>: Int' type=kotlin.Int origin=null
+            CALL 'getValue(Any?, KProperty<*>) on MutableMap<in String, out Int>: Int' type=kotlin.Int origin=null
               <V>: Int
+              <V1 : V>: Int
               $receiver: GET_FIELD '`test8$delegate`: HashMap<String, Int> /* = HashMap<String, Int> */' type=kotlin.collections.HashMap<kotlin.String, kotlin.Int> /* = java.util.HashMap<kotlin.String, kotlin.Int> */ origin=null
                 receiver: GET_VAR 'this@C: C' type=C origin=null
               thisRef: GET_VAR 'this@C: C' type=C origin=null

compiler/testData/ir/irText/declarations/delegatedProperties.txt

@@ -65,8 +65,9 @@ FILE /delegatedProperties.kt
         $this: VALUE_PARAMETER this@C: C
         BLOCK_BODY
           RETURN type=kotlin.Nothing from='<get-test3>(): Any'
-            CALL 'getValue(Any?, KProperty<*>) on MutableMap<in String, in Any>: Any' type=kotlin.Any origin=null
+            CALL 'getValue(Any?, KProperty<*>) on MutableMap<in String, out Any>: Any' type=kotlin.Any origin=null
               <V>: Any
+              <V1 : V>: Any
               $receiver: GET_FIELD '`test3$delegate`: MutableMap<String, Any>' type=kotlin.collections.MutableMap<kotlin.String, kotlin.Any> origin=null
                 receiver: GET_VAR 'this@C: C' type=C origin=null
               thisRef: GET_VAR 'this@C: C' type=C origin=null
@@ -99,8 +100,9 @@ FILE /delegatedProperties.kt
     FUN DELEGATED_PROPERTY_ACCESSOR public fun <get-test4>(): kotlin.Any
       BLOCK_BODY
         RETURN type=kotlin.Nothing from='<get-test4>(): Any'
-          CALL 'getValue(Any?, KProperty<*>) on MutableMap<in String, in Any>: Any' type=kotlin.Any origin=null
+          CALL 'getValue(Any?, KProperty<*>) on MutableMap<in String, out Any>: Any' type=kotlin.Any origin=null
             <V>: Any
+            <V1 : V>: Any
             $receiver: GET_FIELD '`test4$delegate`: HashMap<String, Any> /* = HashMap<String, Any> */' type=kotlin.collections.HashMap<kotlin.String, kotlin.Any> /* = java.util.HashMap<kotlin.String, kotlin.Any> */ origin=null
             thisRef: CONST Null type=kotlin.Nothing? value='null'
             property: PROPERTY_REFERENCE 'test4: Any' field=null getter='<get-test4>(): Any' setter='<set-test4>(Any): Unit' type=kotlin.reflect.KMutableProperty0<kotlin.Any> origin=PROPERTY_REFERENCE_FOR_DELEGATE

compiler/testData/ir/irText/declarations/localDelegatedProperties.txt

@@ -31,8 +31,9 @@ FILE /localDelegatedProperties.kt
         FUN DELEGATED_PROPERTY_ACCESSOR local final fun <get-x>(): kotlin.Int
           BLOCK_BODY
             RETURN type=kotlin.Nothing from='<get-x>(): Int'
-              CALL 'getValue(Any?, KProperty<*>) on MutableMap<in String, in Int>: Int' type=kotlin.Int origin=null
+              CALL 'getValue(Any?, KProperty<*>) on MutableMap<in String, out Int>: Int' type=kotlin.Int origin=null
                 <V>: Int
+                <V1 : V>: Int
                 $receiver: GET_VAR '`x$delegate`: HashMap<String, Int> /* = HashMap<String, Int> */' type=kotlin.collections.HashMap<kotlin.String, kotlin.Int> /* = java.util.HashMap<kotlin.String, kotlin.Int> */ origin=null
                 thisRef: CONST Null type=kotlin.Nothing? value='null'
                 property: LOCAL_DELEGATED_PROPERTY_REFERENCE 'x: Int' delegate='`x$delegate`: HashMap<String, Int> /* = HashMap<String, Int> */' getter='<get-x>(): Int' setter='<set-x>(Int): Unit' type=kotlin.reflect.KMutableProperty0<kotlin.Int> origin=PROPERTY_REFERENCE_FOR_DELEGATE

compiler/testData/ir/irText/declarations/packageLevelProperties.txt

@@ -87,8 +87,9 @@ FILE /packageLevelProperties.kt
     FUN DELEGATED_PROPERTY_ACCESSOR public fun <get-test8>(): kotlin.Int
       BLOCK_BODY
         RETURN type=kotlin.Nothing from='<get-test8>(): Int'
-          CALL 'getValue(Any?, KProperty<*>) on MutableMap<in String, in Int>: Int' type=kotlin.Int origin=null
+          CALL 'getValue(Any?, KProperty<*>) on MutableMap<in String, out Int>: Int' type=kotlin.Int origin=null
             <V>: Int
+            <V1 : V>: Int
             $receiver: GET_FIELD '`test8$delegate`: HashMap<String, Int> /* = HashMap<String, Int> */' type=kotlin.collections.HashMap<kotlin.String, kotlin.Int> /* = java.util.HashMap<kotlin.String, kotlin.Int> */ origin=null
             thisRef: CONST Null type=kotlin.Nothing? value='null'
             property: PROPERTY_REFERENCE 'test8: Int' field=null getter='<get-test8>(): Int' setter='<set-test8>(Int): Unit' type=kotlin.reflect.KMutableProperty0<kotlin.Int> origin=PROPERTY_REFERENCE_FOR_DELEGATE

libraries/stdlib/src/kotlin/collections/MapAccessors.kt

@@ -26,8 +26,8 @@ public inline operator fun <V, V1: V> Map<in String, @Exact V>.getValue(thisRef:
  */
 @kotlin.jvm.JvmName("getVar")
 @kotlin.internal.InlineOnly
-public inline operator fun <V> MutableMap<in String, in V>.getValue(thisRef: Any?, property: KProperty<*>): V
+public inline operator fun <V, V1: V> MutableMap<in String, out @Exact V>.getValue(thisRef: Any?, property: KProperty<*>): V1
-        = @Suppress("UNCHECKED_CAST") (getOrImplicitDefault(property.name) as V)
+        = @Suppress("UNCHECKED_CAST") (getOrImplicitDefault(property.name) as V1)
 
 /**
  * Stores the value of the property for the given object in this mutable map.

libraries/stdlib/test/properties/delegation/MapAccessorsTest.kt

@@ -5,6 +5,8 @@ import kotlin.test.*
 class ValByMapExtensionsTest {
     val map: Map<String, String> = hashMapOf("a" to "all", "b" to "bar", "c" to "code")
     val genericMap = mapOf<String, Any?>("i" to 1, "x" to 1.0)
+    val mmapOut: MutableMap<String, out String> = mutableMapOf("g" to "out", "g1" to "in")
+    val genericMmapOut: MutableMap<String, out Any?> = mmapOut
 
     val a by map
     val b: String by map
@@ -12,6 +14,8 @@ class ValByMapExtensionsTest {
     val d: String? by map
     val e: String by map.withDefault { "default" }
     val f: String? by map.withDefault { null }
+    val g: String by mmapOut
+    val g1: String by genericMmapOut
     // val n: Int by map // prohibited by type system
     val i: Int by genericMap
     val x: Double by genericMap
@@ -23,6 +27,8 @@ class ValByMapExtensionsTest {
         assertEquals("code", c)
         assertEquals("default", e)
         assertEquals(null, f)
+        assertEquals("out", g)
+        assertEquals("in", g1)
         assertEquals(1, i)
         assertEquals(1.0, x)
         assertFailsWith<NoSuchElementException> { d }