backing fields resolve changed

KT-462 Consider allowing initializing properties via property names when it is safe
KT-598 Allow to use backing fields after this expression

compiler/testData/diagnostics/tests/backingField/ReadInFunction.jet

@@ -1,4 +1,4 @@
 class ReadByAnotherPropertyInitializer() {
     val a = 1
-    fun ff() = <!UNRESOLVED_REFERENCE!>$a<!>
+    fun ff() = $a
 }

compiler/testData/diagnostics/tests/backingField/ReadNonexistentAbstractPropertyInAnonymous.jet

@@ -2,6 +2,6 @@ abstract class ReadNonexistent() {
     abstract val aa: Int
     
     {
-        val x = <!NO_BACKING_FIELD!>$aa<!>
+        val x = <!NO_BACKING_FIELD_ABSTRACT_PROPERTY!>$aa<!>
     }
-}
+}

compiler/testData/diagnostics/tests/backingField/ReadNonexistentAbstractPropertyInFunction.jet

@@ -1,5 +1,5 @@
 abstract class ReadNonexistent {
     abstract val aa: Int
     
-    fun ff() = <!UNRESOLVED_REFERENCE!>$aa<!>
-}
+    fun ff() = <!NO_BACKING_FIELD_ABSTRACT_PROPERTY!>$aa<!>
+}

compiler/testData/diagnostics/tests/backingField/ReadNonexistentCustomGetInAnonymous.jet

@@ -3,6 +3,6 @@ class ReadNonexistent() {
         get() = 1
 
     {
-        val x = <!NO_BACKING_FIELD!>$a<!>
+        val x = <!NO_BACKING_FIELD_CUSTOM_ACCESSORS!>$a<!>
     }
-}
+}

compiler/testData/diagnostics/tests/backingField/ReadNonexistentCustomGetInAnotherInitializer.jet

@@ -2,5 +2,5 @@ class CustomValNoBackingField() {
     val a: Int
         get() = 1
     
-    val b = <!NO_BACKING_FIELD!>$a<!>
-}
+    val b = <!NO_BACKING_FIELD_CUSTOM_ACCESSORS!>$a<!>
+}

compiler/testData/diagnostics/tests/backingField/ReadNonexistentDeclaredInHigher.jet

@@ -1,7 +1,6 @@
-val y = 1
-
-class A() {
-    {
-        val x = <!UNRESOLVED_REFERENCE!>$y<!>
-    }
-}
+class CustomValNoBackingField() {
+    val a: Int
+        get() = 1
+    
+    val b = <!NO_BACKING_FIELD_CUSTOM_ACCESSORS!>$a<!>
+}

compiler/testData/diagnostics/tests/backingField/WriteNonexistentDeclaredInHigher.jet

@@ -2,6 +2,6 @@ val y = 1
 
 class A() {
     {
-        <!UNRESOLVED_REFERENCE!>$y<!> = 1
+        <!INACCESSIBLE_BACKING_FIELD!>$y<!> = 1
     }
-}
+}

compiler/testData/diagnostics/tests/backingField/kt462BackingFieldsResolve.jet

@@ -0,0 +1,172 @@
+//KT-462 Consider allowing initializing properties via property names when it is safe
+//KT-598 Allow to use backing fields after this expression
+
+namespace kt462
+
+abstract class TestInitializationWithoutBackingField() {
+    val valWithBackingField : Int
+    {
+        valWithBackingField = 2
+    }
+
+    val valWithoutBackingField : Int
+    get() = 42
+    {
+        <!VAL_REASSIGNMENT!>valWithoutBackingField<!> = 45
+    }
+
+    var finalDefaultVar : Int
+    {
+        finalDefaultVar = 3
+    }
+
+    open var openVar : Int
+    {
+        <!INITIALIZATION_USING_BACKING_FIELD_OPEN_SETTER!>openVar<!> = 4
+    }
+
+    var varWithCustomSetter : Int
+    set(v: Int) {
+        $varWithCustomSetter = v
+    }
+    {
+        <!INITIALIZATION_USING_BACKING_FIELD_CUSTOM_SETTER!>varWithCustomSetter<!> = 3
+    }
+
+    var varWithoutBackingField : Int
+    get() = 3
+    set(v: Int) {}
+    {
+        varWithoutBackingField = 4
+    }
+
+    abstract var abstractVar : Int
+    {
+        abstractVar = 34
+    }
+}
+
+abstract class TestInitializationThroughBackingField() {
+    val valWithBackingField : Int
+    {
+        $valWithBackingField = 2
+    }
+
+    val valWithoutBackingField : Int
+    get() = 42
+    {
+        <!NO_BACKING_FIELD_CUSTOM_ACCESSORS!>$valWithoutBackingField<!> = 45
+    }
+
+    var finalDefaultVar : Int
+    {
+        $finalDefaultVar = 3
+    }
+
+    open var openVar : Int
+    {
+        $openVar = 4
+    }
+
+    var varWithCustomSetter : Int
+    set(v: Int) {
+        $varWithCustomSetter = v
+    }
+    {
+        $varWithCustomSetter = 3
+    }
+
+    var varWithoutBackingField : Int
+    get() = 3
+    set(v: Int) {}
+    {
+        <!NO_BACKING_FIELD_CUSTOM_ACCESSORS!>$varWithoutBackingField<!> = 4
+    }
+
+    abstract var abstractVar : Int
+    {
+        <!NO_BACKING_FIELD_ABSTRACT_PROPERTY!>$abstractVar<!> = 34
+    }
+}
+
+class TestBackingFieldsVisibility() {
+    var a : Int = 712
+    {
+        $a = 37
+        this.$a = 357
+    }
+
+    fun foo() {
+        $a = 334
+        this.$a = 347
+    }
+
+    fun foo(a: TestBackingFieldsVisibility) {
+        val <!UNUSED_VARIABLE!>b<!> : Int = 3
+        <!UNRESOLVED_REFERENCE!>$b<!> = 342
+        <!INACCESSIBLE_BACKING_FIELD!>a.$a<!> = 3
+    }
+
+    val x = <!INACCESSIBLE_BACKING_FIELD!>$namespaceLevelVar<!>
+
+    class Inner() {
+        val z = this@TestBackingFieldsVisibility.$x
+    }
+
+    <!ABSTRACT_PROPERTY_IN_NON_ABSTRACT_CLASS!>abstract<!> val w = 11
+    get() = $w //test there is no second error here
+}
+
+val namespaceLevelVar = 11
+
+class T() {
+    val z : Int get() = 42
+
+    {
+        <!NO_BACKING_FIELD_CUSTOM_ACCESSORS!>this.$z<!> = 34
+    }
+
+    fun foo() {
+        <!NO_BACKING_FIELD_CUSTOM_ACCESSORS!>this.$z<!> = 343
+    }
+
+    val a =  object {
+        val x = <!NO_BACKING_FIELD_CUSTOM_ACCESSORS, NO_BACKING_FIELD_CUSTOM_ACCESSORS!>$z<!>
+        {
+            <!NO_BACKING_FIELD_CUSTOM_ACCESSORS, NO_BACKING_FIELD_CUSTOM_ACCESSORS!>$z<!> = 23
+        }
+    }
+
+    var x: Int = 2
+    get() {
+        val <!UNUSED_VARIABLE!>o<!> = object {
+            {
+                $x = 34
+            }
+            fun foo() {
+                $x = 23
+            }
+        }
+        return 1
+    }
+
+    var r: Int = $x
+    set(v: Int) {
+        if (true) {
+            $r = 33
+        }
+        else {
+            $r = 35
+        }
+    }
+
+    fun bar() {
+        $x = 34
+        val <!UNUSED_VARIABLE!>o<!> = object {
+            val y = $x
+            {
+                $x = 422
+            }
+        }
+    }
+}