diff --git a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerFirTestdataTestGenerated.java b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerFirTestdataTestGenerated.java
index e502a56ede2..0f5e8b81996 100644
--- a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerFirTestdataTestGenerated.java
+++ b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerFirTestdataTestGenerated.java
@@ -3533,6 +3533,12 @@ public class DiagnosisCompilerFirTestdataTestGenerated extends AbstractDiagnosis
                 runTest("compiler/fir/analysis-tests/testData/resolve/smartcasts/kt39000.kt");
             }
 
+            @Test
+            @TestMetadata("kt50788.kt")
+            public void testKt50788() throws Exception {
+                runTest("compiler/fir/analysis-tests/testData/resolve/smartcasts/kt50788.kt");
+            }
+
             @Test
             @TestMetadata("multipleCasts.kt")
             public void testMultipleCasts() throws Exception {
diff --git a/compiler/fir/analysis-tests/legacy-fir-tests/tests-gen/org/jetbrains/kotlin/fir/LazyBodyIsNotTouchedTilContractsPhaseTestGenerated.java b/compiler/fir/analysis-tests/legacy-fir-tests/tests-gen/org/jetbrains/kotlin/fir/LazyBodyIsNotTouchedTilContractsPhaseTestGenerated.java
index 4ec2d348fcc..f4c6432ebab 100644
--- a/compiler/fir/analysis-tests/legacy-fir-tests/tests-gen/org/jetbrains/kotlin/fir/LazyBodyIsNotTouchedTilContractsPhaseTestGenerated.java
+++ b/compiler/fir/analysis-tests/legacy-fir-tests/tests-gen/org/jetbrains/kotlin/fir/LazyBodyIsNotTouchedTilContractsPhaseTestGenerated.java
@@ -3124,6 +3124,11 @@ public class LazyBodyIsNotTouchedTilContractsPhaseTestGenerated extends Abstract
             runTest("compiler/fir/analysis-tests/testData/resolve/smartcasts/kt39000.kt");
         }
 
+        @TestMetadata("kt50788.kt")
+        public void testKt50788() throws Exception {
+            runTest("compiler/fir/analysis-tests/testData/resolve/smartcasts/kt50788.kt");
+        }
+
         @TestMetadata("multipleCasts.kt")
         public void testMultipleCasts() throws Exception {
             runTest("compiler/fir/analysis-tests/testData/resolve/smartcasts/multipleCasts.kt");
diff --git a/compiler/fir/analysis-tests/testData/resolve/smartcasts/kt50788.fir.txt b/compiler/fir/analysis-tests/testData/resolve/smartcasts/kt50788.fir.txt
new file mode 100644
index 00000000000..123697c878a
--- /dev/null
+++ b/compiler/fir/analysis-tests/testData/resolve/smartcasts/kt50788.fir.txt
@@ -0,0 +1,5 @@
+FILE: main.kt
+    public final fun <T : R|kotlin/CharSequence?|> foo(mapper: R|Mapper|, cls: R|java/lang/Class<T>?|): R|kotlin/Unit| {
+        lval result: R|T & Any| = R|<local>/mapper|.R|/Mapper.readValue|<R|ft<T, T?>|>(R|<local>/cls|)!!
+        R|<local>/result|.R|kotlin/CharSequence.length|
+    }
diff --git a/compiler/fir/analysis-tests/testData/resolve/smartcasts/kt50788.kt b/compiler/fir/analysis-tests/testData/resolve/smartcasts/kt50788.kt
new file mode 100644
index 00000000000..e9073ef5219
--- /dev/null
+++ b/compiler/fir/analysis-tests/testData/resolve/smartcasts/kt50788.kt
@@ -0,0 +1,14 @@
+// ISSUE: KT-50788
+// FILE: Mapper.java
+public class Mapper {
+    public <T> T readValue(Class<T> valueType) {
+        return null;
+    }
+}
+
+// FILE: main.kt
+
+fun <T : CharSequence?> foo(mapper: Mapper, cls: Class<T>?) {
+    val result = <!DEBUG_INFO_EXPRESSION_TYPE("T!!")!>mapper.readValue<T>(cls)!!<!> // The type of result is expected to be T & Any here, but in fact it's just T
+    result.length
+}
diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirDiagnosticTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirDiagnosticTestGenerated.java
index f09a039f0b6..e21a64aa19a 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirDiagnosticTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirDiagnosticTestGenerated.java
@@ -3533,6 +3533,12 @@ public class FirDiagnosticTestGenerated extends AbstractFirDiagnosticTest {
                 runTest("compiler/fir/analysis-tests/testData/resolve/smartcasts/kt39000.kt");
             }
 
+            @Test
+            @TestMetadata("kt50788.kt")
+            public void testKt50788() throws Exception {
+                runTest("compiler/fir/analysis-tests/testData/resolve/smartcasts/kt50788.kt");
+            }
+
             @Test
             @TestMetadata("multipleCasts.kt")
             public void testMultipleCasts() throws Exception {
diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirDiagnosticsWithLightTreeTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirDiagnosticsWithLightTreeTestGenerated.java
index 9408754e207..32335c972a0 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirDiagnosticsWithLightTreeTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirDiagnosticsWithLightTreeTestGenerated.java
@@ -3533,6 +3533,12 @@ public class FirDiagnosticsWithLightTreeTestGenerated extends AbstractFirDiagnos
                 runTest("compiler/fir/analysis-tests/testData/resolve/smartcasts/kt39000.kt");
             }
 
+            @Test
+            @TestMetadata("kt50788.kt")
+            public void testKt50788() throws Exception {
+                runTest("compiler/fir/analysis-tests/testData/resolve/smartcasts/kt50788.kt");
+            }
+
             @Test
             @TestMetadata("multipleCasts.kt")
             public void testMultipleCasts() throws Exception {
diff --git a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt
index a09bab186c6..f72e8a46ed1 100644
--- a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt
+++ b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt
@@ -57,7 +57,7 @@ private fun ConeTypeContext.makesSenseToBeDefinitelyNotNull(type: ConeKotlinType
     is ConeTypeParameterType -> type.isNullableType()
     // Actually, this branch should work for type parameters as well, but it breaks some cases. See KT-40114.
     // Basically, if we have `T : X..X?`, then `T <: Any` but we still have `T` != `T & Any`.
-    is ConeTypeVariableType, is ConeCapturedType ->
+    is ConeTypeVariableType, is ConeCapturedType, is ConeFlexibleType ->
         !AbstractNullabilityChecker.isSubtypeOfAny(
             newTypeCheckerState(errorTypesEqualToAnything = false, stubTypesEqualToAnything = false), type
         )
@@ -73,7 +73,7 @@ fun ConeDefinitelyNotNullType.Companion.create(
 ): ConeDefinitelyNotNullType? {
     return when {
         original is ConeDefinitelyNotNullType -> original
-        typeContext.makesSenseToBeDefinitelyNotNull(original) -> ConeDefinitelyNotNullType(original)
+        typeContext.makesSenseToBeDefinitelyNotNull(original) -> ConeDefinitelyNotNullType(original.coneLowerBoundIfFlexible())
         else -> null
     }
 }
diff --git a/compiler/testData/diagnostics/tests/inference/builderInference/stubTypes/commonSuperTypeContravariant.fir.kt b/compiler/testData/diagnostics/tests/inference/builderInference/stubTypes/commonSuperTypeContravariant.fir.kt
index e1980d1a743..59b4dc1f4a6 100644
--- a/compiler/testData/diagnostics/tests/inference/builderInference/stubTypes/commonSuperTypeContravariant.fir.kt
+++ b/compiler/testData/diagnostics/tests/inference/builderInference/stubTypes/commonSuperTypeContravariant.fir.kt
@@ -77,8 +77,8 @@ fun test() {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.String?")!>select2(Test.foo(get()), getIn())<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.String?")!>select3(get(), getIn())<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.String?")!>select3(get(), Test.foo(getIn()))<!>
-        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.String?")!>select3(Test.foo(get()), Test.foo(getIn()))<!>
-        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.String?")!>select3(Test.foo(get()), getIn())<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.String")!>select3(Test.foo(get()), Test.foo(getIn()))<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.String")!>select3(Test.foo(get()), getIn())<!>
         ""
     }
 }