diff --git a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
index 7c6b36fe522..594241dbafd 100644
--- a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
+++ b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
@@ -36936,6 +36936,18 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                 KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/testsWithStdLib/builderInference"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.(fir|ll)\\.kts?$"), true);
             }
 
+            @Test
+            @TestMetadata("buildListToUpperBound.kt")
+            public void testBuildListToUpperBound() throws Exception {
+                runTest("compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBound.kt");
+            }
+
+            @Test
+            @TestMetadata("buildListToUpperBoundForbidden.kt")
+            public void testBuildListToUpperBoundForbidden() throws Exception {
+                runTest("compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBoundForbidden.kt");
+            }
+
             @Test
             @TestMetadata("completeIrrelevantCalls.kt")
             public void testCompleteIrrelevantCalls() throws Exception {
@@ -36966,12 +36978,6 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                 runTest("compiler/testData/diagnostics/testsWithStdLib/builderInference/kt48445.kt");
             }
 
-            @Test
-            @TestMetadata("kt50520.kt")
-            public void testKt50520() throws Exception {
-                runTest("compiler/testData/diagnostics/testsWithStdLib/builderInference/kt50520.kt");
-            }
-
             @Test
             @TestMetadata("resolveUsualCallWithBuilderInference.kt")
             public void testResolveUsualCallWithBuilderInference() throws Exception {
diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java
index 068f4f3d38e..ac691d3c85e 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java
@@ -36936,6 +36936,18 @@ public class FirLightTreeOldFrontendDiagnosticsTestGenerated extends AbstractFir
                 KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/testsWithStdLib/builderInference"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.(fir|ll)\\.kts?$"), true);
             }
 
+            @Test
+            @TestMetadata("buildListToUpperBound.kt")
+            public void testBuildListToUpperBound() throws Exception {
+                runTest("compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBound.kt");
+            }
+
+            @Test
+            @TestMetadata("buildListToUpperBoundForbidden.kt")
+            public void testBuildListToUpperBoundForbidden() throws Exception {
+                runTest("compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBoundForbidden.kt");
+            }
+
             @Test
             @TestMetadata("completeIrrelevantCalls.kt")
             public void testCompleteIrrelevantCalls() throws Exception {
@@ -36966,12 +36978,6 @@ public class FirLightTreeOldFrontendDiagnosticsTestGenerated extends AbstractFir
                 runTest("compiler/testData/diagnostics/testsWithStdLib/builderInference/kt48445.kt");
             }
 
-            @Test
-            @TestMetadata("kt50520.kt")
-            public void testKt50520() throws Exception {
-                runTest("compiler/testData/diagnostics/testsWithStdLib/builderInference/kt50520.kt");
-            }
-
             @Test
             @TestMetadata("resolveUsualCallWithBuilderInference.kt")
             public void testResolveUsualCallWithBuilderInference() throws Exception {
diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java
index 7df67be31c2..482ee574d47 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java
@@ -37032,6 +37032,18 @@ public class FirPsiOldFrontendDiagnosticsTestGenerated extends AbstractFirPsiDia
                 KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/testsWithStdLib/builderInference"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.(fir|ll)\\.kts?$"), true);
             }
 
+            @Test
+            @TestMetadata("buildListToUpperBound.kt")
+            public void testBuildListToUpperBound() throws Exception {
+                runTest("compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBound.kt");
+            }
+
+            @Test
+            @TestMetadata("buildListToUpperBoundForbidden.kt")
+            public void testBuildListToUpperBoundForbidden() throws Exception {
+                runTest("compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBoundForbidden.kt");
+            }
+
             @Test
             @TestMetadata("completeIrrelevantCalls.kt")
             public void testCompleteIrrelevantCalls() throws Exception {
@@ -37062,12 +37074,6 @@ public class FirPsiOldFrontendDiagnosticsTestGenerated extends AbstractFirPsiDia
                 runTest("compiler/testData/diagnostics/testsWithStdLib/builderInference/kt48445.kt");
             }
 
-            @Test
-            @TestMetadata("kt50520.kt")
-            public void testKt50520() throws Exception {
-                runTest("compiler/testData/diagnostics/testsWithStdLib/builderInference/kt50520.kt");
-            }
-
             @Test
             @TestMetadata("resolveUsualCallWithBuilderInference.kt")
             public void testResolveUsualCallWithBuilderInference() throws Exception {
diff --git a/compiler/testData/diagnostics/testsWithStdLib/builderInference/kt50520.fir.kt b/compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBound.fir.kt
similarity index 65%
rename from compiler/testData/diagnostics/testsWithStdLib/builderInference/kt50520.fir.kt
rename to compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBound.fir.kt
index caecd7bc5a2..d41665a4dbf 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/builderInference/kt50520.fir.kt
+++ b/compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBound.fir.kt
@@ -1,5 +1,6 @@
 // WITH_STDLIB
-// SKIP_TXT
+// !LANGUAGE: -ForbidInferringPostponedTypeVariableIntoDeclaredUpperBound
+// ISSUE: KT-50520
 
 fun box(): String {
     <!NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>buildList<!> {
diff --git a/compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBound.kt b/compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBound.kt
new file mode 100644
index 00000000000..909030f40d5
--- /dev/null
+++ b/compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBound.kt
@@ -0,0 +1,11 @@
+// WITH_STDLIB
+// !LANGUAGE: -ForbidInferringPostponedTypeVariableIntoDeclaredUpperBound
+// ISSUE: KT-50520
+
+fun box(): String {
+    buildList {
+        val foo = { first() }
+        add(0, foo)
+    }
+    return "OK"
+}
diff --git a/compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBoundForbidden.fir.kt b/compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBoundForbidden.fir.kt
new file mode 100644
index 00000000000..940e3b75847
--- /dev/null
+++ b/compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBoundForbidden.fir.kt
@@ -0,0 +1,11 @@
+// WITH_STDLIB
+// !LANGUAGE: +ForbidInferringPostponedTypeVariableIntoDeclaredUpperBound
+// ISSUE: KT-56169
+
+fun box(): String {
+    <!NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>buildList<!> {
+        val foo = { first() }
+        add(0, foo)
+    }
+    return "OK"
+}
diff --git a/compiler/testData/diagnostics/testsWithStdLib/builderInference/kt50520.kt b/compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBoundForbidden.kt
similarity index 69%
rename from compiler/testData/diagnostics/testsWithStdLib/builderInference/kt50520.kt
rename to compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBoundForbidden.kt
index ad138c6b4c1..9c7eec512a8 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/builderInference/kt50520.kt
+++ b/compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBoundForbidden.kt
@@ -1,5 +1,6 @@
 // WITH_STDLIB
-// SKIP_TXT
+// !LANGUAGE: +ForbidInferringPostponedTypeVariableIntoDeclaredUpperBound
+// ISSUE: KT-56169
 
 fun box(): String {
     <!NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>buildList<!> {
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
index f4da82fb65b..e9ac1337f4d 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
@@ -37032,6 +37032,18 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/testsWithStdLib/builderInference"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.(fir|ll)\\.kts?$"), true);
             }
 
+            @Test
+            @TestMetadata("buildListToUpperBound.kt")
+            public void testBuildListToUpperBound() throws Exception {
+                runTest("compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBound.kt");
+            }
+
+            @Test
+            @TestMetadata("buildListToUpperBoundForbidden.kt")
+            public void testBuildListToUpperBoundForbidden() throws Exception {
+                runTest("compiler/testData/diagnostics/testsWithStdLib/builderInference/buildListToUpperBoundForbidden.kt");
+            }
+
             @Test
             @TestMetadata("completeIrrelevantCalls.kt")
             public void testCompleteIrrelevantCalls() throws Exception {
@@ -37062,12 +37074,6 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 runTest("compiler/testData/diagnostics/testsWithStdLib/builderInference/kt48445.kt");
             }
 
-            @Test
-            @TestMetadata("kt50520.kt")
-            public void testKt50520() throws Exception {
-                runTest("compiler/testData/diagnostics/testsWithStdLib/builderInference/kt50520.kt");
-            }
-
             @Test
             @TestMetadata("resolveUsualCallWithBuilderInference.kt")
             public void testResolveUsualCallWithBuilderInference() throws Exception {