FIR: report UNSAFE_CALL on dot when possible

compiler/testData/diagnostics/testsWithStdLib/smartcasts/letChangesToNotNull.fir.kt

@@ -1,7 +0,0 @@
-// KT-9051: Allow smart cast for captured variables if they are not modified
-
-fun foo(y: String?) {
-    var x: String? = null
-    y?.let { x = it }
-    x.<!UNSAFE_CALL!>length<!> // Smart cast is not possible
-}

compiler/testData/diagnostics/testsWithStdLib/smartcasts/letChangesToNotNull.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // KT-9051: Allow smart cast for captured variables if they are not modified
 
 fun foo(y: String?) {

compiler/testData/diagnostics/testsWithStdLib/smartcasts/letChangesToNullComplex.fir.kt

@@ -5,7 +5,7 @@ fun bar(z: String?) = z
 fun foo(y: String?) {
     var x: String? = ""
     if (x != null) {
-        bar(y?.let { x = null; it }).<!UNSAFE_CALL!>length<!>
+        bar(y?.let { x = null; it })<!UNSAFE_CALL!>.<!>length
         x.length // Smart cast is not possible
     }
 }

compiler/testData/diagnostics/testsWithStdLib/smartcasts/withChangesToNull.fir.kt

@@ -2,7 +2,7 @@ fun foo(y: String?) {
     var x: String? = ""
     if (x != null) {
         with(y?.let { x = null; it }) {
-            this.<!UNSAFE_CALL!>length<!>
+            this<!UNSAFE_CALL!>.<!>length
             x.length
         }
         x.length