[FIR] Fix clearing info about DF variable after reassignment

compiler/fir/analysis-tests/legacy-fir-tests/tests-gen/org/jetbrains/kotlin/fir/LazyBodyIsNotTouchedTilContractsPhaseTestGenerated.java

@@ -3141,6 +3141,11 @@ public class LazyBodyIsNotTouchedTilContractsPhaseTestGenerated extends Abstract
                 runTest("compiler/fir/analysis-tests/testData/resolve/smartcasts/safeCalls/boundSafeCallAndIsCheck.kt");
             }
 
+            @TestMetadata("complexIfWithOr.kt")
+            public void testComplexIfWithOr() throws Exception {
+                runTest("compiler/fir/analysis-tests/testData/resolve/smartcasts/safeCalls/complexIfWithOr.kt");
+            }
+
             @TestMetadata("safeCallAndEqualityToBool.kt")
             public void testSafeCallAndEqualityToBool() throws Exception {
                 runTest("compiler/fir/analysis-tests/testData/resolve/smartcasts/safeCalls/safeCallAndEqualityToBool.kt");

compiler/fir/analysis-tests/testData/resolve/smartcasts/safeCalls/complexIfWithOr.fir.txt

@@ -0,0 +1,19 @@
+FILE: complexIfWithOr.kt
+    public abstract interface State : R|kotlin/Any| {
+    }
+    public abstract interface Complex : R|kotlin/Any| {
+        public abstract val superClass: R|Complex?|
+            public get(): R|Complex?|
+
+    }
+    public abstract interface ExceptionState : R|State| {
+    }
+    public final fun test(qualifier: R|State?|): R|kotlin/Unit| {
+        when () {
+            ==(R|<local>/qualifier|, Null(null)) || (R|<local>/qualifier| is R|ExceptionState|) || ==((R|<local>/qualifier| as? R|Complex|)?.{ $subj$.R|/Complex.superClass| }, Null(null)) ->  {
+                ^test Unit
+            }
+        }
+
+        R|<local>/qualifier|.R|/Complex.superClass|
+    }

compiler/fir/analysis-tests/testData/resolve/smartcasts/safeCalls/complexIfWithOr.kt

@@ -0,0 +1,13 @@
+interface State
+interface Complex {
+    val superClass: Complex?
+}
+
+interface ExceptionState : State
+
+fun test(qualifier: State?) {
+    if (qualifier == null || qualifier is ExceptionState || (qualifier as? Complex)?.superClass == null) {
+        return
+    }
+    qualifier.superClass
+}

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirDiagnosticTestGenerated.java

@@ -3520,6 +3520,12 @@ public class FirDiagnosticTestGenerated extends AbstractFirDiagnosticTest {
                     runTest("compiler/fir/analysis-tests/testData/resolve/smartcasts/safeCalls/boundSafeCallAndIsCheck.kt");
                 }
 
+                @Test
+                @TestMetadata("complexIfWithOr.kt")
+                public void testComplexIfWithOr() throws Exception {
+                    runTest("compiler/fir/analysis-tests/testData/resolve/smartcasts/safeCalls/complexIfWithOr.kt");
+                }
+
                 @Test
                 @TestMetadata("safeCallAndEqualityToBool.kt")
                 public void testSafeCallAndEqualityToBool() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirDiagnosticsWithLightTreeTestGenerated.java

@@ -3566,6 +3566,12 @@ public class FirDiagnosticsWithLightTreeTestGenerated extends AbstractFirDiagnos
                     runTest("compiler/fir/analysis-tests/testData/resolve/smartcasts/safeCalls/boundSafeCallAndIsCheck.kt");
                 }
 
+                @Test
+                @TestMetadata("complexIfWithOr.kt")
+                public void testComplexIfWithOr() throws Exception {
+                    runTest("compiler/fir/analysis-tests/testData/resolve/smartcasts/safeCalls/complexIfWithOr.kt");
+                }
+
                 @Test
                 @TestMetadata("safeCallAndEqualityToBool.kt")
                 public void testSafeCallAndEqualityToBool() throws Exception {