FIR checker: differentiate UNSAFE_CALL from INAPPLICABLE_CANDIDATE

To do so, inside the root cause of inapplicable candidate errors,
we will record expected/actual type of receiver, if any.
That will help identifying inapplicable calls on nullable receiver.

compiler/testData/diagnostics/tests/smartCasts/varnotnull/assignment.fir.kt

@@ -1,11 +1,11 @@
 // !WITH_NEW_INFERENCE
 fun foo() {
     var v: String? = null
-    v.<!INAPPLICABLE_CANDIDATE!>length<!>
+    v.<!UNSAFE_CALL!>length<!>
     v = "abc"
     v.length
     v = null
-    v.<!INAPPLICABLE_CANDIDATE!>length<!>
+    v.<!UNSAFE_CALL!>length<!>
     v = "abc"
     v.length
 }

compiler/testData/diagnostics/tests/smartCasts/varnotnull/boundInitializerWrong.fir.kt

@@ -23,7 +23,7 @@ fun bar(s: String?) {
     val hashCode = ss?.hashCode()
     ss = null
     if (hashCode != null) {
-        ss.<!INAPPLICABLE_CANDIDATE!>hashCode<!>()
+        ss.<!UNSAFE_CALL!>hashCode<!>()
     }
 }
 
@@ -41,6 +41,6 @@ fun baz(arg: Some?) {
     val ss = arg?.s
     if (ss != null) {
         arg.hashCode()
-        arg.s.<!INAPPLICABLE_CANDIDATE!>hashCode<!>()
+        arg.s.<!UNSAFE_CALL!>hashCode<!>()
     }
 }

compiler/testData/diagnostics/tests/smartCasts/varnotnull/initInTryReturnInCatch.fir.kt

@@ -37,7 +37,7 @@ fun test3() {
     catch (e: B) {
         return
     }
-    a.<!INAPPLICABLE_CANDIDATE!>hashCode<!>() // a is nullable here
+    a.<!UNSAFE_CALL!>hashCode<!>() // a is nullable here
 }
 fun test4() {
     var a: Int? = null
@@ -50,7 +50,7 @@ fun test4() {
     catch (e: B) {
         return
     }
-    a.<!INAPPLICABLE_CANDIDATE!>hashCode<!>() // a is nullable here
+    a.<!UNSAFE_CALL!>hashCode<!>() // a is nullable here
 }
 fun test5() {
     var a: Int?// = null
@@ -76,5 +76,5 @@ fun test6() {
     finally {
         a = null
     }
-    a.<!INAPPLICABLE_CANDIDATE!>hashCode<!>() // a is null here
+    a.<!UNSAFE_CALL!>hashCode<!>() // a is null here
 }

compiler/testData/diagnostics/tests/smartCasts/varnotnull/initialization.fir.kt

@@ -2,7 +2,7 @@
 fun foo() {
     var v: String? = "xyz"
     // It is possible in principle to provide smart cast here
-    v.<!INAPPLICABLE_CANDIDATE!>length<!>
+    v.<!UNSAFE_CALL!>length<!>
     v = null
-    v.<!INAPPLICABLE_CANDIDATE!>length<!>
+    v.<!UNSAFE_CALL!>length<!>
 }

compiler/testData/diagnostics/tests/smartCasts/varnotnull/nestedWhile.fir.kt

@@ -12,7 +12,7 @@ fun foo(): Bar {
     var y: Bar? = Bar()
     while (x != null) {
         // Here call is unsafe because of initialization and also inner loop
-        y.<!INAPPLICABLE_CANDIDATE!>next<!>()
+        y.<!UNSAFE_CALL!>next<!>()
         while (y != null) {
             if (x == y)
                 // x is not null because of outer while

compiler/testData/diagnostics/tests/smartCasts/varnotnull/plusplusMinusminus.fir.kt

@@ -12,7 +12,7 @@ operator fun Long?.inc() = this?.let { it + 1 }
 fun bar(arg: Long?): Long {
     var i = arg
     if (i++ == 5L) {
-        return i<!INAPPLICABLE_CANDIDATE!>--<!> + i
+        return i<!UNSAFE_CALL!>--<!> + i
     }
     if (i++ == 7L) {
         return i++ <!NONE_APPLICABLE!>+<!> i

compiler/testData/diagnostics/tests/smartCasts/varnotnull/postfixNullableIncrement.fir.kt

@@ -3,6 +3,6 @@ operator fun Int?.inc(): Int? { return this }
 public fun box(arg: Int?) : Int? {
     var i : Int? = arg
     var j = i++
-    j.<!INAPPLICABLE_CANDIDATE!>toInt<!>()
+    j.<!UNSAFE_CALL!>toInt<!>()
     return i
 }

compiler/testData/diagnostics/tests/smartCasts/varnotnull/prefixNullableClassIncrement.fir.kt

@@ -9,5 +9,5 @@ public fun box() {
     // type of j should be MyClass?
     var j = ++i
     // j is null so call should be unsafe
-    j.<!INAPPLICABLE_CANDIDATE!>hashCode<!>()
+    j.<!UNSAFE_CALL!>hashCode<!>()
 }

compiler/testData/diagnostics/tests/smartCasts/varnotnull/prefixNullableIncrement.fir.kt

@@ -3,6 +3,6 @@ operator fun Int?.inc(): Int? { return this }
 public fun box(arg: Int?) : Int? {
     var i = arg
     var j = ++i
-    j.<!INAPPLICABLE_CANDIDATE!>toInt<!>()
+    j.<!UNSAFE_CALL!>toInt<!>()
     return ++j
 }

compiler/testData/diagnostics/tests/smartCasts/varnotnull/setNotNullInTry.fir.kt

@@ -10,5 +10,5 @@ fun foo() {
     } catch (ex: Exception) {}
     bar(s)
     if (s != null) { }
-    s.<!INAPPLICABLE_CANDIDATE!>hashCode<!>()
+    s.<!UNSAFE_CALL!>hashCode<!>()
 }

compiler/testData/diagnostics/tests/smartCasts/varnotnull/setNullInTry.fir.kt

@@ -6,5 +6,5 @@ fun foo() {
     try {
         s = null
     } catch (ex: Exception) {}
-    s.<!INAPPLICABLE_CANDIDATE!>hashCode<!>()
+    s.<!UNSAFE_CALL!>hashCode<!>()
 }

compiler/testData/diagnostics/tests/smartCasts/varnotnull/setNullInTryFinally.fir.kt

@@ -12,5 +12,5 @@ fun foo() {
     finally {
         bar()
     }
-    s.<!INAPPLICABLE_CANDIDATE!>hashCode<!>()
+    s.<!UNSAFE_CALL!>hashCode<!>()
 }

compiler/testData/diagnostics/tests/smartCasts/varnotnull/setNullInTryUnsound.fir.kt

@@ -6,5 +6,5 @@ fun foo() {
     try {
         s = null
     } catch (ex: Exception) {}
-    s.<!INAPPLICABLE_CANDIDATE!>hashCode<!>()
+    s.<!UNSAFE_CALL!>hashCode<!>()
 }

compiler/testData/diagnostics/tests/smartCasts/varnotnull/unnecessaryWithMap.fir.kt

@@ -14,7 +14,7 @@ class MyClass {
         var res = 0
         m = create()
         // See KT-7428
-        <!INAPPLICABLE_CANDIDATE!>for ((k, v) in m)
+        <!UNSAFE_CALL!>for ((k, v) in m)
             res += (k.length + v.length)<!>
         return res
     }

compiler/testData/diagnostics/tests/smartCasts/varnotnull/varNull.fir.kt

@@ -2,5 +2,5 @@
 fun foo(): Int {
     var s: String? = "abc"
     s = null
-    return s.<!INAPPLICABLE_CANDIDATE!>length<!>
+    return s.<!UNSAFE_CALL!>length<!>
 }