'createDelegate' operator convention:

- resolution & inference
- additional diagnostic for language feature support

compiler/testData/diagnostics/tests/delegatedProperty/createDelegate/genericCreateDelegate.kt

@@ -0,0 +1,13 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+class Cell<out V>(val value: V)
+
+class GenericDelegate<V>(val value: V)
+
+operator fun <T> T.createDelegate(a: Any?, p: Any?) = GenericDelegate(this)
+
+operator fun <W> GenericDelegate<W>.getValue(a: Any?, p: Any?) = Cell(value)
+
+val test1: Cell<String> by "OK"
+val test2: Cell<Any> by "OK"
+val test3 by "OK"

compiler/testData/diagnostics/tests/delegatedProperty/createDelegate/genericCreateDelegate.txt

@@ -0,0 +1,23 @@
+package
+
+public val test1: Cell<kotlin.String>
+public val test2: Cell<kotlin.Any>
+public val test3: Cell<kotlin.String>
+public operator fun </*0*/ T> T.createDelegate(/*0*/ a: kotlin.Any?, /*1*/ p: kotlin.Any?): GenericDelegate<T>
+public operator fun </*0*/ W> GenericDelegate<W>.getValue(/*0*/ a: kotlin.Any?, /*1*/ p: kotlin.Any?): Cell<W>
+
+public final class Cell</*0*/ out V> {
+    public constructor Cell</*0*/ out V>(/*0*/ value: V)
+    public final val value: V
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class GenericDelegate</*0*/ V> {
+    public constructor GenericDelegate</*0*/ V>(/*0*/ value: V)
+    public final val value: V
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/delegatedProperty/createDelegate/noOperatorModifierOnCreateDelegate.kt

@@ -0,0 +1,17 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+import kotlin.reflect.KProperty
+
+class StringDelegate(val s: String) {
+    operator fun getValue(a: Any?, p: KProperty<*>): Int = 42
+}
+
+// NB no operator
+fun String.createDelegate(a: Any?, p: KProperty<*>) = StringDelegate(this)
+
+operator fun String.getValue(a: Any?, p: KProperty<*>) = this
+
+val test1: String by "OK"
+val test2: Int by <!DELEGATE_SPECIAL_FUNCTION_RETURN_TYPE_MISMATCH!>"OK"<!>
+val test3 by "OK"
+

compiler/testData/diagnostics/tests/delegatedProperty/createDelegate/noOperatorModifierOnCreateDelegate.txt

@@ -0,0 +1,16 @@
+package
+
+public val test1: kotlin.String
+public val test2: kotlin.Int
+public val test3: kotlin.String
+public fun kotlin.String.createDelegate(/*0*/ a: kotlin.Any?, /*1*/ p: kotlin.reflect.KProperty<*>): StringDelegate
+public operator fun kotlin.String.getValue(/*0*/ a: kotlin.Any?, /*1*/ p: kotlin.reflect.KProperty<*>): kotlin.String
+
+public final class StringDelegate {
+    public constructor StringDelegate(/*0*/ s: kotlin.String)
+    public final val s: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final operator fun getValue(/*0*/ a: kotlin.Any?, /*1*/ p: kotlin.reflect.KProperty<*>): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/delegatedProperty/createDelegate/simpleCreateDelegate.kt

@@ -0,0 +1,10 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+import kotlin.reflect.KProperty
+
+operator fun String.createDelegate(a: Any?, p: KProperty<*>) = this
+operator fun String.getValue(a: Any?, p: KProperty<*>) = this
+
+val test1: String by "OK"
+
+val test2 by "OK"

compiler/testData/diagnostics/tests/delegatedProperty/createDelegate/simpleCreateDelegate.txt

@@ -0,0 +1,6 @@
+package
+
+public val test1: kotlin.String
+public val test2: kotlin.String
+public operator fun kotlin.String.createDelegate(/*0*/ a: kotlin.Any?, /*1*/ p: kotlin.reflect.KProperty<*>): kotlin.String
+public operator fun kotlin.String.getValue(/*0*/ a: kotlin.Any?, /*1*/ p: kotlin.reflect.KProperty<*>): kotlin.String

compiler/testData/diagnostics/tests/delegatedProperty/createDelegate/unsupportedOperatorCreateDelegate.kt

@@ -0,0 +1,14 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+// !LANGUAGE: -OperatorCreateDelegate
+
+class WrongDelegate(val x: Int) {
+    operator fun getValue(thisRef: Any?, prop: Any): Int = x
+}
+
+<!UNSUPPORTED_FEATURE(only available since Kotlin 1.1: operator createDelegate)!>operator<!> fun String.createDelegate(thisRef: Any?, prop: Any) = WrongDelegate(this.length)
+
+operator fun String.getValue(thisRef: Any?, prop: Any) = this
+
+val test1: String by "OK"
+val test2: Int by <!DELEGATE_SPECIAL_FUNCTION_RETURN_TYPE_MISMATCH!>"OK"<!>
+val test3 by "OK"

compiler/testData/diagnostics/tests/delegatedProperty/createDelegate/unsupportedOperatorCreateDelegate.txt

@@ -0,0 +1,16 @@
+package
+
+public val test1: kotlin.String
+public val test2: kotlin.Int
+public val test3: kotlin.String
+public operator fun kotlin.String.createDelegate(/*0*/ thisRef: kotlin.Any?, /*1*/ prop: kotlin.Any): WrongDelegate
+public operator fun kotlin.String.getValue(/*0*/ thisRef: kotlin.Any?, /*1*/ prop: kotlin.Any): kotlin.String
+
+public final class WrongDelegate {
+    public constructor WrongDelegate(/*0*/ x: kotlin.Int)
+    public final val x: kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final operator fun getValue(/*0*/ thisRef: kotlin.Any?, /*1*/ prop: kotlin.Any): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}