FIR: Choose a resolved candidate for augmented assignment when both

assign and operator candidates are unsuccessful.

compiler/testData/diagnostics/tests/BinaryCallsOnNullableValues.fir.kt

@@ -8,7 +8,7 @@ fun f(): Unit {
     x <!UNSAFE_OPERATOR_CALL!>+<!> 1
     x <!UNSAFE_INFIX_CALL!>plus<!> 1
     x <!UNSAFE_OPERATOR_CALL!><<!> 1
-    x <!UNRESOLVED_REFERENCE!>+=<!> 1
+    x <!UNSAFE_OPERATOR_CALL!>+=<!> 1
 
     x == 1
     x != 1

compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/augmentedAssignment.fir.kt

@@ -1,17 +0,0 @@
-class A {
-    operator fun plusAssign(s: String) {}
-}
-
-fun test() {
-    var a: A? = A()
-    a <!UNSAFE_OPERATOR_CALL!>+=<!> ""
-}
-
-class B {
-    operator fun plus(other: B) = this
-}
-
-fun test2() {
-    var b: B? = B()
-    b <!UNRESOLVED_REFERENCE!>+=<!> B()
-}

compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/augmentedAssignment.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 class A {
     operator fun plusAssign(s: String) {}
 }

compiler/testData/diagnostics/tests/operatorsOverloading/assignmentOperationsCheckReturnType.fir.kt

@@ -1,14 +1,14 @@
 fun intBinEq() {
     var x = 0
-    x <!UNRESOLVED_REFERENCE!>+=<!> 'a'
+    x <!NONE_APPLICABLE!>+=<!> 'a'
     x += 1.toByte()
     x += 1.toShort()
     <!ASSIGNMENT_TYPE_MISMATCH!>x += 1L<!>
     <!ASSIGNMENT_TYPE_MISMATCH!>x += 1f<!>
     <!ASSIGNMENT_TYPE_MISMATCH!>x += 1.0<!>
-    x <!UNRESOLVED_REFERENCE!>*=<!> 'a'
-    <!ASSIGNMENT_TYPE_MISMATCH!>x *= 1.toByte()<!>
-    <!ASSIGNMENT_TYPE_MISMATCH!>x *= 1.toShort()<!>
+    x <!NONE_APPLICABLE!>*=<!> 'a'
+    x *= 1.toByte()
+    x *= 1.toShort()
     <!ASSIGNMENT_TYPE_MISMATCH!>x *= 1L<!>
     <!ASSIGNMENT_TYPE_MISMATCH!>x *= 1f<!>
     <!ASSIGNMENT_TYPE_MISMATCH!>x *= 1.0<!>
@@ -16,16 +16,16 @@ fun intBinEq() {
 
 fun shortBinEq() {
     var x = 0.toShort()
-    x <!UNRESOLVED_REFERENCE!>+=<!> 'a'
+    x <!NONE_APPLICABLE!>+=<!> 'a'
     x += 1.toByte()
     x += 1.toShort()
     <!ASSIGNMENT_TYPE_MISMATCH!>x += 1L<!>
     <!ASSIGNMENT_TYPE_MISMATCH!>x += 1f<!>
     <!ASSIGNMENT_TYPE_MISMATCH!>x += 1.0<!>
 
-    x <!UNRESOLVED_REFERENCE!>*=<!> 'a'
-    <!ASSIGNMENT_TYPE_MISMATCH!>x *= 1.toByte()<!>
-    <!ASSIGNMENT_TYPE_MISMATCH!>x *= 1.toShort()<!>
+    x <!NONE_APPLICABLE!>*=<!> 'a'
+    x *= 1.toByte()
+    x *= 1.toShort()
     <!ASSIGNMENT_TYPE_MISMATCH!>x *= 1L<!>
     <!ASSIGNMENT_TYPE_MISMATCH!>x *= 1f<!>
     <!ASSIGNMENT_TYPE_MISMATCH!>x *= 1.0<!>

compiler/testData/diagnostics/tests/smartCasts/alwaysNull.fir.kt

@@ -7,7 +7,7 @@ fun foo(): String {
     var t: String? = "y"
     if (t == null) t = "x"
     var x: Int? = null
-    if (x == null) x <!UNRESOLVED_REFERENCE!>+=<!> null
+    if (x == null) x <!UNSAFE_OPERATOR_CALL!>+=<!> null
     return t + s
 }