[FIR] Extract non-null info from x?.y!! ^KT-44513 Fixed

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/FirDataFlowAnalyzer.kt

@@ -654,16 +654,28 @@ abstract class FirDataFlowAnalyzer<FLOW : Flow>(
         // Add `Any` to the set of possible types; the intersection type `T? & Any` will be reduced to `T` after smartcast.
         val (node, unionNode) = graphBuilder.exitCheckNotNullCall(checkNotNullCall, callCompleted)
         node.mergeIncomingFlow()
-        val argument = checkNotNullCall.argument
-        variableStorage.getOrCreateRealVariable(node.previousFlow, argument.symbol, argument)?.let { operandVariable ->
-            node.flow.addTypeStatement(operandVariable typeEq any)
-            logicSystem.approveStatementsInsideFlow(
-                node.flow,
-                operandVariable notEq null,
-                shouldRemoveSynthetics = true,
-                shouldForkFlow = false
-            )
+
+        fun FirExpression.propagateNotNullInfo() {
+            val symbol = this.symbol
+            if (symbol != null) {
+                variableStorage.getOrCreateRealVariable(node.previousFlow, symbol, this)?.let { operandVariable ->
+                    node.flow.addTypeStatement(operandVariable typeEq any)
+                    logicSystem.approveStatementsInsideFlow(
+                        node.flow,
+                        operandVariable notEq null,
+                        shouldRemoveSynthetics = true,
+                        shouldForkFlow = false
+                    )
+                }
+            }
+            when (this) {
+                is FirSafeCallExpression -> this.receiver.propagateNotNullInfo()
+                is FirTypeOperatorCall -> this.argument.propagateNotNullInfo()
+            }
         }
+
+        checkNotNullCall.argument.propagateNotNullInfo()
+
         unionNode?.let { unionFlowFromArguments(it) }
     }
 

compiler/testData/diagnostics/tests/inference/nestedCalls/makeNullableIfSafeCall.fir.kt

@@ -1,41 +0,0 @@
-package a
-
-interface A {
-    val b: B
-    val nb: B?
-}
-
-interface B {
-    fun foo(): Int
-}
-
-fun test(u: A?, x: A?, y: A?, z: A?, w: A, v: A?) {
-    u?.b?.foo()!! // was UNNECESSARY_SAFE_CALL everywhere, because result type (of 'foo()') wasn't made nullable
-    u!!.b<!UNNECESSARY_SAFE_CALL!>?.<!>foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
-    x?.b!!.foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
-    // x?.b is not null
-    x<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.b<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
-
-    y?.nb?.foo()!!
-    y!!.nb?.foo()!!
-    z?.nb!!.foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
-    // z?.nb is not null
-    z<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.nb!!.foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
-
-    w.b<!UNNECESSARY_SAFE_CALL!>?.<!>foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
-    w.b<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
-    w.nb?.foo()!!
-    w.nb!!.foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
-
-    v!!.b.foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
-}
-
-fun B?.bar(): Int = 1
-fun B?.baz(): Int? = 1
-
-fun doInt(i: Int) = i
-
-fun test(a: A?) {
-    doInt(a?.b.bar()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>)
-    doInt(a?.b.baz()!!)
-}

compiler/testData/diagnostics/tests/inference/nestedCalls/makeNullableIfSafeCall.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 package a
 
 interface A {

compiler/testData/diagnostics/tests/inference/regressions/kt702.fir.kt

@@ -1,20 +0,0 @@
-//KT-702 Type inference failed
-package a
-//+JDK
-
-fun <T> getJavaClass() : java.lang.Class<T> { <!NO_RETURN_IN_FUNCTION_WITH_BLOCK_BODY!>}<!>
-
-public class Throwables() {
-    companion object {
-        public fun <X : Throwable?> propagateIfInstanceOf(throwable : Throwable?, declaredType : Class<X?>?) : Unit {
-            if (((throwable != null) && declaredType?.isInstance(throwable)!!))
-            {
-                throw declaredType?.cast(throwable)!!
-            }
-        }
-        public fun propagateIfPossible(throwable : Throwable?) : Unit {
-            propagateIfInstanceOf(throwable, getJavaClass<Error?>()) // Type inference failed: Mismatch while expanding constraints
-            propagateIfInstanceOf(throwable, getJavaClass<RuntimeException?>()) // Type inference failed: Mismatch while expanding constraints
-        }
-    }
-}

compiler/testData/diagnostics/tests/inference/regressions/kt702.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 //KT-702 Type inference failed
 package a
 //+JDK

compiler/testData/diagnostics/tests/regressions/kt701.fir.kt

@@ -6,7 +6,7 @@ public class Throwables() {
         public fun <X : Throwable?> propagateIfInstanceOf(throwable : Throwable?, declaredType : Class<X?>?) {
             if (((throwable != null) && declaredType?.isInstance(throwable)!!))
             {
-                throw declaredType?.cast(throwable)!!
+                throw declaredType<!UNNECESSARY_SAFE_CALL!>?.<!>cast(throwable)!!
             }
         }
         public fun propagateIfPossible(throwable : Throwable?) {

compiler/testData/diagnostics/tests/smartCasts/level_1_0.fir.kt

@@ -36,7 +36,7 @@ fun kt6840_2(s: String?) {
 
 fun kt1635(s: String?) {
     s?.hashCode()!!
-    s<!UNSAFE_CALL!>.<!>hashCode()
+    s.hashCode()
 }
 
 fun kt2127() {

compiler/testData/diagnostics/tests/smartCasts/safecalls/safeAccessReceiverNotNull.fir.kt

@@ -18,7 +18,7 @@ fun kt6840_2(s: String?) {
 
 fun kt1635(s: String?) {
     s?.hashCode()!!
-    s<!UNSAFE_CALL!>.<!>hashCode()
+    s.hashCode()
 }
 
 fun kt2127() {