diff --git a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosticCompilerTestFE10TestdataTestGenerated.java b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosticCompilerTestFE10TestdataTestGenerated.java
index 4e3b7ec5837..6cc10628406 100644
--- a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosticCompilerTestFE10TestdataTestGenerated.java
+++ b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosticCompilerTestFE10TestdataTestGenerated.java
@@ -6867,6 +6867,12 @@ public class DiagnosticCompilerTestFE10TestdataTestGenerated extends AbstractDia
                     runTest("compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/expressionInUnitLiteral.kt");
                 }
 
+                @Test
+                @TestMetadata("initializationInUnreachableCode.kt")
+                public void testInitializationInUnreachableCode() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/initializationInUnreachableCode.kt");
+                }
+
                 @Test
                 @TestMetadata("kt2585_1.kt")
                 public void testKt2585_1() throws Exception {
diff --git a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated.java b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated.java
index a52ea545c2e..91dfea84756 100644
--- a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated.java
+++ b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated.java
@@ -6867,6 +6867,12 @@ public class LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated
                     runTest("compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/expressionInUnitLiteral.kt");
                 }
 
+                @Test
+                @TestMetadata("initializationInUnreachableCode.kt")
+                public void testInitializationInUnreachableCode() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/initializationInUnreachableCode.kt");
+                }
+
                 @Test
                 @TestMetadata("kt2585_1.kt")
                 public void testKt2585_1() 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 e9a13e8ad9f..ac14b283c10 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
@@ -6867,6 +6867,12 @@ public class FirLightTreeOldFrontendDiagnosticsTestGenerated extends AbstractFir
                     runTest("compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/expressionInUnitLiteral.kt");
                 }
 
+                @Test
+                @TestMetadata("initializationInUnreachableCode.kt")
+                public void testInitializationInUnreachableCode() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/initializationInUnreachableCode.kt");
+                }
+
                 @Test
                 @TestMetadata("kt2585_1.kt")
                 public void testKt2585_1() 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 b9d56b93d2d..259c1dd17c9 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
@@ -6873,6 +6873,12 @@ public class FirPsiOldFrontendDiagnosticsTestGenerated extends AbstractFirPsiDia
                     runTest("compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/expressionInUnitLiteral.kt");
                 }
 
+                @Test
+                @TestMetadata("initializationInUnreachableCode.kt")
+                public void testInitializationInUnreachableCode() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/initializationInUnreachableCode.kt");
+                }
+
                 @Test
                 @TestMetadata("kt2585_1.kt")
                 public void testKt2585_1() throws Exception {
diff --git a/compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/initializationInUnreachableCode.fir.kt b/compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/initializationInUnreachableCode.fir.kt
new file mode 100644
index 00000000000..57eab53cc8d
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/initializationInUnreachableCode.fir.kt
@@ -0,0 +1,13 @@
+// COMPARE_WITH_LIGHT_TREE
+// ISSUE: KT-40851
+
+fun error(): Nothing = throw Exception()
+
+<!UNREACHABLE_CODE{LT}!>class Some<!UNREACHABLE_CODE{PSI}!>()<!> {
+    var x: Int
+    val y: Int =<!> error()
+
+    <!UNREACHABLE_CODE{LT}!>init {
+        <!UNREACHABLE_CODE!>x = 1<!>;
+    }
+}<!>
diff --git a/compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/initializationInUnreachableCode.kt b/compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/initializationInUnreachableCode.kt
new file mode 100644
index 00000000000..e4c1cee7fc0
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/initializationInUnreachableCode.kt
@@ -0,0 +1,13 @@
+// COMPARE_WITH_LIGHT_TREE
+// ISSUE: KT-40851
+
+fun error(): Nothing = throw Exception()
+
+class Some() {
+    <!MUST_BE_INITIALIZED_OR_BE_ABSTRACT!>var x: Int<!>
+    val y: Int = error()
+
+    init {
+        x = 1;
+    }
+}
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 8167d6ec406..e5f57f3c7db 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
@@ -6873,6 +6873,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                     runTest("compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/expressionInUnitLiteral.kt");
                 }
 
+                @Test
+                @TestMetadata("initializationInUnreachableCode.kt")
+                public void testInitializationInUnreachableCode() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/initializationInUnreachableCode.kt");
+                }
+
                 @Test
                 @TestMetadata("kt2585_1.kt")
                 public void testKt2585_1() throws Exception {