[FE] Prohibit missed MUST_BE_INITIALIZED when there is no primary constructor

^KT-58472 Fixed
Review: https://jetbrains.team/p/kt/reviews/9967

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDataClassConverters.kt

@@ -2851,6 +2851,12 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.MUST_BE_INITIALIZED_WARNING) { firDiagnostic ->
+        MustBeInitializedWarningImpl(
+            firDiagnostic as KtPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.MUST_BE_INITIALIZED_OR_BE_FINAL) { firDiagnostic ->
         MustBeInitializedOrBeFinalImpl(
             firDiagnostic as KtPsiDiagnostic,
@@ -2869,6 +2875,12 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.MUST_BE_INITIALIZED_OR_BE_ABSTRACT_WARNING) { firDiagnostic ->
+        MustBeInitializedOrBeAbstractWarningImpl(
+            firDiagnostic as KtPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT) { firDiagnostic ->
         MustBeInitializedOrFinalOrAbstractImpl(
             firDiagnostic as KtPsiDiagnostic,

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnostics.kt

@@ -2019,6 +2019,10 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         override val diagnosticClass get() = MustBeInitialized::class
     }
 
+    abstract class MustBeInitializedWarning : KtFirDiagnostic<KtProperty>() {
+        override val diagnosticClass get() = MustBeInitializedWarning::class
+    }
+
     abstract class MustBeInitializedOrBeFinal : KtFirDiagnostic<KtProperty>() {
         override val diagnosticClass get() = MustBeInitializedOrBeFinal::class
     }
@@ -2031,6 +2035,10 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         override val diagnosticClass get() = MustBeInitializedOrBeAbstract::class
     }
 
+    abstract class MustBeInitializedOrBeAbstractWarning : KtFirDiagnostic<KtProperty>() {
+        override val diagnosticClass get() = MustBeInitializedOrBeAbstractWarning::class
+    }
+
     abstract class MustBeInitializedOrFinalOrAbstract : KtFirDiagnostic<KtProperty>() {
         override val diagnosticClass get() = MustBeInitializedOrFinalOrAbstract::class
     }

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnosticsImpl.kt

@@ -2425,6 +2425,11 @@ internal class MustBeInitializedImpl(
     override val token: KtLifetimeToken,
 ) : KtFirDiagnostic.MustBeInitialized(), KtAbstractFirDiagnostic<KtProperty>
 
+internal class MustBeInitializedWarningImpl(
+    override val firDiagnostic: KtPsiDiagnostic,
+    override val token: KtLifetimeToken,
+) : KtFirDiagnostic.MustBeInitializedWarning(), KtAbstractFirDiagnostic<KtProperty>
+
 internal class MustBeInitializedOrBeFinalImpl(
     override val firDiagnostic: KtPsiDiagnostic,
     override val token: KtLifetimeToken,
@@ -2440,6 +2445,11 @@ internal class MustBeInitializedOrBeAbstractImpl(
     override val token: KtLifetimeToken,
 ) : KtFirDiagnostic.MustBeInitializedOrBeAbstract(), KtAbstractFirDiagnostic<KtProperty>
 
+internal class MustBeInitializedOrBeAbstractWarningImpl(
+    override val firDiagnostic: KtPsiDiagnostic,
+    override val token: KtLifetimeToken,
+) : KtFirDiagnostic.MustBeInitializedOrBeAbstractWarning(), KtAbstractFirDiagnostic<KtProperty>
+
 internal class MustBeInitializedOrFinalOrAbstractImpl(
     override val firDiagnostic: KtPsiDiagnostic,
     override val token: KtLifetimeToken,

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosticCompilerTestFE10TestdataTestGenerated.java

@@ -3037,6 +3037,124 @@ public class DiagnosticCompilerTestFE10TestdataTestGenerated extends AbstractDia
             public void testVarDeferredInitInOpenClass() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/backingField/VarDeferredInitInOpenClass.kt");
             }
+
+            @Nested
+            @TestMetadata("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor")
+            @TestDataPath("$PROJECT_ROOT")
+            public class ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor {
+                @Test
+                public void testAllFilesPresentInProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor() throws Exception {
+                    KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.(reversed|fir|ll)\\.kts?$"), true, "multiplatform");
+                }
+
+                @Test
+                @TestMetadata("implicitPrimaryConstructor_errorAnyway.kt")
+                public void testImplicitPrimaryConstructor_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/implicitPrimaryConstructor_errorAnyway.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneInheritedSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_oneInheritedSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneInheritedSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneInheritedSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneInheritedSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneInheritedSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValError_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_openValError_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValError_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValError_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_openValError_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValError_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValWarning_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_openValWarning_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValWarning_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValWarning_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_openValWarning_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValWarning_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openVar_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_openVar_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openVar_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openVar_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_openVar_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openVar_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_partialDeferredInitInSecondary_errorAnyway.kt")
+                public void testNoPrimary_partialDeferredInitInSecondary_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_partialDeferredInitInSecondary_errorAnyway.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_partialDeferredInitInTwoSecondaries_errorAnyway.kt")
+                public void testNoPrimary_partialDeferredInitInTwoSecondaries_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_partialDeferredInitInTwoSecondaries_errorAnyway.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_twoSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_twoSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_twoSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_twoSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_twoSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_twoSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("onePrimary_oneSecondary_errorAnyway.kt")
+                public void testOnePrimary_oneSecondary_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/onePrimary_oneSecondary_errorAnyway.kt");
+                }
+            }
         }
 
         @Nested

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated.java

@@ -3037,6 +3037,124 @@ public class LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated
             public void testVarDeferredInitInOpenClass() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/backingField/VarDeferredInitInOpenClass.kt");
             }
+
+            @Nested
+            @TestMetadata("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor")
+            @TestDataPath("$PROJECT_ROOT")
+            public class ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor {
+                @Test
+                public void testAllFilesPresentInProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor() throws Exception {
+                    KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.(reversed|fir|ll)\\.kts?$"), true, "multiplatform");
+                }
+
+                @Test
+                @TestMetadata("implicitPrimaryConstructor_errorAnyway.kt")
+                public void testImplicitPrimaryConstructor_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/implicitPrimaryConstructor_errorAnyway.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneInheritedSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_oneInheritedSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneInheritedSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneInheritedSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneInheritedSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneInheritedSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValError_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_openValError_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValError_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValError_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_openValError_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValError_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValWarning_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_openValWarning_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValWarning_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValWarning_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_openValWarning_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValWarning_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openVar_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_openVar_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openVar_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openVar_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_openVar_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openVar_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_partialDeferredInitInSecondary_errorAnyway.kt")
+                public void testNoPrimary_partialDeferredInitInSecondary_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_partialDeferredInitInSecondary_errorAnyway.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_partialDeferredInitInTwoSecondaries_errorAnyway.kt")
+                public void testNoPrimary_partialDeferredInitInTwoSecondaries_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_partialDeferredInitInTwoSecondaries_errorAnyway.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_twoSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_twoSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_twoSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_twoSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_twoSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_twoSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("onePrimary_oneSecondary_errorAnyway.kt")
+                public void testOnePrimary_oneSecondary_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/onePrimary_oneSecondary_errorAnyway.kt");
+                }
+            }
         }
 
         @Nested

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

@@ -3037,6 +3037,124 @@ public class FirLightTreeOldFrontendDiagnosticsTestGenerated extends AbstractFir
             public void testVarDeferredInitInOpenClass() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/backingField/VarDeferredInitInOpenClass.kt");
             }
+
+            @Nested
+            @TestMetadata("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor")
+            @TestDataPath("$PROJECT_ROOT")
+            public class ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor {
+                @Test
+                public void testAllFilesPresentInProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor() throws Exception {
+                    KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.(reversed|fir|ll)\\.kts?$"), true, "multiplatform");
+                }
+
+                @Test
+                @TestMetadata("implicitPrimaryConstructor_errorAnyway.kt")
+                public void testImplicitPrimaryConstructor_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/implicitPrimaryConstructor_errorAnyway.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneInheritedSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_oneInheritedSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneInheritedSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneInheritedSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneInheritedSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneInheritedSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValError_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_openValError_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValError_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValError_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_openValError_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValError_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValWarning_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_openValWarning_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValWarning_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValWarning_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_openValWarning_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValWarning_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openVar_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_openVar_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openVar_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openVar_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_openVar_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openVar_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_partialDeferredInitInSecondary_errorAnyway.kt")
+                public void testNoPrimary_partialDeferredInitInSecondary_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_partialDeferredInitInSecondary_errorAnyway.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_partialDeferredInitInTwoSecondaries_errorAnyway.kt")
+                public void testNoPrimary_partialDeferredInitInTwoSecondaries_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_partialDeferredInitInTwoSecondaries_errorAnyway.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_twoSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_twoSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_twoSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_twoSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_twoSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_twoSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("onePrimary_oneSecondary_errorAnyway.kt")
+                public void testOnePrimary_oneSecondary_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/onePrimary_oneSecondary_errorAnyway.kt");
+                }
+            }
         }
 
         @Nested

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

@@ -3043,6 +3043,124 @@ public class FirPsiOldFrontendDiagnosticsTestGenerated extends AbstractFirPsiDia
             public void testVarDeferredInitInOpenClass() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/backingField/VarDeferredInitInOpenClass.kt");
             }
+
+            @Nested
+            @TestMetadata("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor")
+            @TestDataPath("$PROJECT_ROOT")
+            public class ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor {
+                @Test
+                public void testAllFilesPresentInProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor() throws Exception {
+                    KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor"), Pattern.compile("^(.*)\\.kts?$"), Pattern.compile("^(.+)\\.(reversed|fir|ll)\\.kts?$"), true, "multiplatform");
+                }
+
+                @Test
+                @TestMetadata("implicitPrimaryConstructor_errorAnyway.kt")
+                public void testImplicitPrimaryConstructor_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/implicitPrimaryConstructor_errorAnyway.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneInheritedSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_oneInheritedSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneInheritedSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneInheritedSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneInheritedSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneInheritedSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValError_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_openValError_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValError_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValError_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_openValError_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValError_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValWarning_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_openValWarning_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValWarning_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValWarning_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_openValWarning_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValWarning_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openVar_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_openVar_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openVar_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openVar_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_openVar_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openVar_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_partialDeferredInitInSecondary_errorAnyway.kt")
+                public void testNoPrimary_partialDeferredInitInSecondary_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_partialDeferredInitInSecondary_errorAnyway.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_partialDeferredInitInTwoSecondaries_errorAnyway.kt")
+                public void testNoPrimary_partialDeferredInitInTwoSecondaries_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_partialDeferredInitInTwoSecondaries_errorAnyway.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_twoSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_twoSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_twoSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_twoSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_twoSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_twoSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("onePrimary_oneSecondary_errorAnyway.kt")
+                public void testOnePrimary_oneSecondary_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/onePrimary_oneSecondary_errorAnyway.kt");
+                }
+            }
         }
 
         @Nested

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt

@@ -1009,9 +1009,11 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
         val PROPERTY_WITH_NO_TYPE_NO_INITIALIZER by error<KtProperty>(PositioningStrategy.DECLARATION_SIGNATURE)
 
         val MUST_BE_INITIALIZED by error<KtProperty>(PositioningStrategy.DECLARATION_SIGNATURE)
+        val MUST_BE_INITIALIZED_WARNING by warning<KtProperty>(PositioningStrategy.DECLARATION_SIGNATURE)
         val MUST_BE_INITIALIZED_OR_BE_FINAL by error<KtProperty>(PositioningStrategy.DECLARATION_SIGNATURE)
         val MUST_BE_INITIALIZED_OR_BE_FINAL_WARNING by warning<KtProperty>(PositioningStrategy.DECLARATION_SIGNATURE)
         val MUST_BE_INITIALIZED_OR_BE_ABSTRACT by error<KtProperty>(PositioningStrategy.DECLARATION_SIGNATURE)
+        val MUST_BE_INITIALIZED_OR_BE_ABSTRACT_WARNING by warning<KtProperty>(PositioningStrategy.DECLARATION_SIGNATURE)
         val MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT by error<KtProperty>(PositioningStrategy.DECLARATION_SIGNATURE)
         val MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT_WARNING by warning<KtProperty>(PositioningStrategy.DECLARATION_SIGNATURE)
 

compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt

@@ -533,9 +533,11 @@ object FirErrors {
     val PROPERTY_INITIALIZER_IN_INTERFACE by error0<KtExpression>()
     val PROPERTY_WITH_NO_TYPE_NO_INITIALIZER by error0<KtProperty>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
     val MUST_BE_INITIALIZED by error0<KtProperty>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
+    val MUST_BE_INITIALIZED_WARNING by warning0<KtProperty>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
     val MUST_BE_INITIALIZED_OR_BE_FINAL by error0<KtProperty>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
     val MUST_BE_INITIALIZED_OR_BE_FINAL_WARNING by warning0<KtProperty>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
     val MUST_BE_INITIALIZED_OR_BE_ABSTRACT by error0<KtProperty>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
+    val MUST_BE_INITIALIZED_OR_BE_ABSTRACT_WARNING by warning0<KtProperty>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
     val MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT by error0<KtProperty>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
     val MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT_WARNING by warning0<KtProperty>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
     val EXTENSION_PROPERTY_MUST_HAVE_ACCESSORS_OR_BE_ABSTRACT by error0<KtProperty>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirTopLevelPropertiesChecker.kt

@@ -12,16 +12,14 @@ import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
+import org.jetbrains.kotlin.diagnostics.KtDiagnosticFactory0
 import org.jetbrains.kotlin.diagnostics.reportOn
 import org.jetbrains.kotlin.fir.analysis.checkers.FirModifierList
 import org.jetbrains.kotlin.fir.analysis.checkers.contains
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.checkers.getModifierList
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
-import org.jetbrains.kotlin.fir.declarations.FirClass
-import org.jetbrains.kotlin.fir.declarations.FirMemberDeclaration
-import org.jetbrains.kotlin.fir.declarations.FirProperty
-import org.jetbrains.kotlin.fir.declarations.FirSimpleFunction
+import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.declarations.impl.FirDefaultPropertyAccessor
 import org.jetbrains.kotlin.fir.declarations.utils.*
 import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeLocalVariableNoTypeOrInitializer
@@ -189,28 +187,42 @@ private fun reportMustBeInitialized(
         !context.languageVersionSettings.supportsFeature(LanguageFeature.ProhibitOpenValDeferredInitialization) &&
                 property.getEffectiveModality(containingClass, context.languageVersionSettings) == Modality.OPEN && property.isVal &&
                 isDefinitelyAssignedInConstructor
-
-    val factory = when {
-        suggestMakingItFinal && suggestMakingItAbstract -> when (isOpenValDeferredInitDeprecationWarning) {
-            true -> FirErrors.MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT_WARNING
-            false -> FirErrors.MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT
-        }
-        suggestMakingItFinal -> when (isOpenValDeferredInitDeprecationWarning) {
-            true -> FirErrors.MUST_BE_INITIALIZED_OR_BE_FINAL_WARNING
-            false -> FirErrors.MUST_BE_INITIALIZED_OR_BE_FINAL
-        }
-        suggestMakingItAbstract -> when (isOpenValDeferredInitDeprecationWarning) {
-            true -> error("Not reachable case. Every \"open val + deferred init\" case that could be made `abstract`, also could be made `final`")
-            false -> FirErrors.MUST_BE_INITIALIZED_OR_BE_ABSTRACT
-        }
-        else -> when (isOpenValDeferredInitDeprecationWarning) {
-            true -> error("Not reachable case. We can always suggest making `open val` property `final`")
-            false -> FirErrors.MUST_BE_INITIALIZED
-        }
+    if (isOpenValDeferredInitDeprecationWarning && !suggestMakingItFinal && suggestMakingItAbstract) {
+        error("Not reachable case. Every \"open val + deferred init\" case that could be made `abstract`, also could be made `final`")
     }
-    reporter.reportOn(propertySource, factory, context)
+    val isMissedMustBeInitializedDeprecationWarning =
+        !context.languageVersionSettings.supportsFeature(LanguageFeature.ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor) &&
+                containingClass != null &&
+                containingClass.primaryConstructorIfAny(context.session) == null &&
+                isDefinitelyAssignedInConstructor
+    val factory = when {
+        suggestMakingItFinal && suggestMakingItAbstract -> FirErrors.MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT
+        suggestMakingItFinal -> FirErrors.MUST_BE_INITIALIZED_OR_BE_FINAL
+        suggestMakingItAbstract -> FirErrors.MUST_BE_INITIALIZED_OR_BE_ABSTRACT
+        else -> FirErrors.MUST_BE_INITIALIZED
+    }
+    if (isOpenValDeferredInitDeprecationWarning && factory == FirErrors.MUST_BE_INITIALIZED) {
+        error("Not reachable case. We can always suggest making `open val` property `final`")
+    }
+    reporter.reportOn(
+        propertySource,
+        when (isMissedMustBeInitializedDeprecationWarning || isOpenValDeferredInitDeprecationWarning) {
+            true -> factory.deprecationWarning
+            false -> factory
+        },
+        context
+    )
 }
 
+private val KtDiagnosticFactory0.deprecationWarning
+    get() = when (this) {
+        FirErrors.MUST_BE_INITIALIZED -> FirErrors.MUST_BE_INITIALIZED_WARNING
+        FirErrors.MUST_BE_INITIALIZED_OR_BE_ABSTRACT -> FirErrors.MUST_BE_INITIALIZED_OR_BE_ABSTRACT_WARNING
+        FirErrors.MUST_BE_INITIALIZED_OR_BE_FINAL -> FirErrors.MUST_BE_INITIALIZED_OR_BE_FINAL_WARNING
+        FirErrors.MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT -> FirErrors.MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT_WARNING
+        else -> error("Only MUST_BE_INITIALIZED is supported")
+    }
+
 private val FirPropertyAccessor?.hasImplementation: Boolean
     get() = (this !is FirDefaultPropertyAccessor && this?.hasBody == true)
 private val FirProperty.hasSetterAccessorImplementation: Boolean

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrorsDefaultMessages.kt

@@ -337,10 +337,12 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MULTIPLE_VARARG_P
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MULTI_FIELD_VALUE_CLASS_PRIMARY_CONSTRUCTOR_DEFAULT_PARAMETER
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MUST_BE_INITIALIZED
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MUST_BE_INITIALIZED_OR_BE_ABSTRACT
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MUST_BE_INITIALIZED_OR_BE_ABSTRACT_WARNING
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MUST_BE_INITIALIZED_OR_BE_FINAL
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MUST_BE_INITIALIZED_OR_BE_FINAL_WARNING
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT_WARNING
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MUST_BE_INITIALIZED_WARNING
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NAMED_ARGUMENTS_NOT_ALLOWED
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NAMED_PARAMETER_NOT_FOUND
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NAME_FOR_AMBIGUOUS_PARAMETER
@@ -1633,9 +1635,11 @@ object FirErrorsDefaultMessages : BaseDiagnosticRendererFactory() {
         map.put(TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM, "Type checking has run into a recursive problem. Easiest workaround: specify types of your declarations explicitly")
 
         map.put(MUST_BE_INITIALIZED, "Property must be initialized")
+        map.put(MUST_BE_INITIALIZED_WARNING, "Property must be initialized. This warning will become an error in future releases.")
         map.put(MUST_BE_INITIALIZED_OR_BE_FINAL, "Property must be initialized or be final")
         map.put(MUST_BE_INITIALIZED_OR_BE_FINAL_WARNING, "Property must be initialized or be final. This warning will become an error in future releases.")
         map.put(MUST_BE_INITIALIZED_OR_BE_ABSTRACT, "Property must be initialized or be abstract")
+        map.put(MUST_BE_INITIALIZED_OR_BE_ABSTRACT_WARNING, "Property must be initialized or be abstract. This warning will become an error in future releases.")
         map.put(MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT, "Property must be initialized, be final, or be abstract")
         map.put(MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT_WARNING, "Property must be initialized, be final, or be abstract. This warning will become an error in future releases.")
 

compiler/frontend/cfg/src/org/jetbrains/kotlin/cfg/ControlFlowInformationProviderImpl.kt

@@ -327,7 +327,7 @@ class ControlFlowInformationProviderImpl private constructor(
     private fun markUninitializedVariables() {
         val varWithUninitializedErrorGenerated = hashSetOf<VariableDescriptor>()
         val varWithValReassignErrorGenerated = hashSetOf<VariableDescriptor>()
-        val processClassOrObject = subroutine is KtClassOrObject
+        val processClassOrObject = subroutine is KtClassOrObject || subroutine is KtSecondaryConstructor
 
         val initializers = pseudocodeVariablesData.variableInitializers
         val declaredVariables = pseudocodeVariablesData.getDeclaredVariables(pseudocode, true)

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java

@@ -673,9 +673,11 @@ public interface Errors {
     DiagnosticFactory0<KtProperty> PROPERTY_WITH_NO_TYPE_NO_INITIALIZER = DiagnosticFactory0.create(ERROR, DECLARATION_SIGNATURE);
 
     DiagnosticFactory0<KtProperty> MUST_BE_INITIALIZED = DiagnosticFactory0.create(ERROR, DECLARATION_SIGNATURE);
+    DiagnosticFactory0<KtProperty> MUST_BE_INITIALIZED_WARNING = DiagnosticFactory0.create(WARNING, DECLARATION_SIGNATURE);
     DiagnosticFactory0<KtProperty> MUST_BE_INITIALIZED_OR_BE_FINAL = DiagnosticFactory0.create(ERROR, DECLARATION_SIGNATURE);
     DiagnosticFactory0<KtProperty> MUST_BE_INITIALIZED_OR_BE_FINAL_WARNING = DiagnosticFactory0.create(WARNING, DECLARATION_SIGNATURE);
     DiagnosticFactory0<KtProperty> MUST_BE_INITIALIZED_OR_BE_ABSTRACT = DiagnosticFactory0.create(ERROR, DECLARATION_SIGNATURE);
+    DiagnosticFactory0<KtProperty> MUST_BE_INITIALIZED_OR_BE_ABSTRACT_WARNING = DiagnosticFactory0.create(WARNING, DECLARATION_SIGNATURE);
     DiagnosticFactory0<KtProperty> MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT = DiagnosticFactory0.create(ERROR, DECLARATION_SIGNATURE);
     DiagnosticFactory0<KtProperty> MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT_WARNING = DiagnosticFactory0.create(WARNING, DECLARATION_SIGNATURE);
 

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java

@@ -307,9 +307,11 @@ public class DefaultErrorMessages {
         MAP.put(BACKING_FIELD_IN_INTERFACE, "Property in an interface cannot have a backing field");
 
         MAP.put(MUST_BE_INITIALIZED, "Property must be initialized");
+        MAP.put(MUST_BE_INITIALIZED_WARNING, "Property must be initialized. This warning will become an error in future releases.");
         MAP.put(MUST_BE_INITIALIZED_OR_BE_FINAL, "Property must be initialized or be final");
         MAP.put(MUST_BE_INITIALIZED_OR_BE_FINAL_WARNING, "Property must be initialized or be final. This warning will become an error in future releases.");
         MAP.put(MUST_BE_INITIALIZED_OR_BE_ABSTRACT, "Property must be initialized or be abstract");
+        MAP.put(MUST_BE_INITIALIZED_OR_BE_ABSTRACT_WARNING, "Property must be initialized or be abstract. This warning will become an error in future releases.");
         MAP.put(MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT, "Property must be initialized, be final, or be abstract");
         MAP.put(MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT_WARNING, "Property must be initialized, be final, or be abstract. This warning will become an error in future releases.");
 

compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.kt

@@ -827,28 +827,40 @@ class DeclarationsChecker(
                     propertyDescriptor.getEffectiveModality(languageVersionSettings) == Modality.OPEN &&
                     !propertyDescriptor.isVar &&
                     trace.bindingContext.get(IS_DEFINITELY_NOT_ASSIGNED_IN_CONSTRUCTOR, propertyDescriptor) == false
-
-        val factory = when {
-            suggestMakingItFinal && suggestMakingItAbstract -> when (isOpenValDeferredInitDeprecationWarning) {
-                true -> MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT_WARNING
-                false -> MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT
-            }
-            suggestMakingItFinal -> when (isOpenValDeferredInitDeprecationWarning) {
-                true -> MUST_BE_INITIALIZED_OR_BE_FINAL_WARNING
-                false -> MUST_BE_INITIALIZED_OR_BE_FINAL
-            }
-            suggestMakingItAbstract -> when (isOpenValDeferredInitDeprecationWarning) {
-                true -> error("Not reachable case. Every \"open val + deferred init\" case that could be made `abstract`, also could be made `final`")
-                false -> MUST_BE_INITIALIZED_OR_BE_ABSTRACT
-            }
-            else -> when (isOpenValDeferredInitDeprecationWarning) {
-                true -> error("Not reachable case. We can always suggest making `open val` property `final`")
-                false -> MUST_BE_INITIALIZED
-            }
+        if (isOpenValDeferredInitDeprecationWarning && !suggestMakingItFinal && suggestMakingItAbstract) {
+            error("Not reachable case. Every \"open val + deferred init\" case that could be made `abstract`, also could be made `final`")
         }
-        trace.report(factory.on(property))
+        val isMissedMustBeInitializedDeprecationWarning =
+            !languageVersionSettings.supportsFeature(LanguageFeature.ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor) &&
+                    containingDeclaration is ClassDescriptor &&
+                    containingDeclaration.constructors.none { it.isPrimary } &&
+                    trace.bindingContext.get(IS_DEFINITELY_NOT_ASSIGNED_IN_CONSTRUCTOR, propertyDescriptor) == false
+        val factory = when {
+            suggestMakingItFinal && suggestMakingItAbstract -> MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT
+            suggestMakingItFinal -> MUST_BE_INITIALIZED_OR_BE_FINAL
+            suggestMakingItAbstract -> MUST_BE_INITIALIZED_OR_BE_ABSTRACT
+            else -> MUST_BE_INITIALIZED
+        }
+        if (isOpenValDeferredInitDeprecationWarning && factory == MUST_BE_INITIALIZED) {
+            error("Not reachable case. We can always suggest making `open val` property `final`")
+        }
+        trace.report(
+            when (isMissedMustBeInitializedDeprecationWarning || isOpenValDeferredInitDeprecationWarning) {
+                true -> factory.deprecationWarning
+                false -> factory
+            }.on(property)
+        )
     }
 
+    private val DiagnosticFactory0<KtProperty>.deprecationWarning: DiagnosticFactory0<KtProperty>
+        get() = when (this) {
+            MUST_BE_INITIALIZED -> MUST_BE_INITIALIZED_WARNING
+            MUST_BE_INITIALIZED_OR_BE_ABSTRACT -> MUST_BE_INITIALIZED_OR_BE_ABSTRACT_WARNING
+            MUST_BE_INITIALIZED_OR_BE_FINAL -> MUST_BE_INITIALIZED_OR_BE_FINAL_WARNING
+            MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT -> MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT_WARNING
+            else -> error("Only MUST_BE_INITIALIZED is supported")
+        }
+
     private fun noExplicitTypeOrGetterType(property: KtProperty) =
         property.typeReference == null
                 && (property.getter == null || (property.getter!!.hasBlockBody() && property.getter!!.returnTypeReference == null))

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/implicitPrimaryConstructor_errorAnyway.kt

@@ -0,0 +1,11 @@
+// FIR_IDENTICAL
+// !LANGUAGE:-ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+class Foo {
+    <!MUST_BE_INITIALIZED!>var x: String<!>
+        set(value) {}
+
+    init {
+        x = ""
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneInheritedSecondary_mustBeInitializedError.kt

@@ -0,0 +1,13 @@
+// FIR_IDENTICAL
+// !LANGUAGE:+ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+open class Base(x: Int)
+class Foo : Base {
+    constructor() : super(1)
+    <!MUST_BE_INITIALIZED!>var x: String<!>
+        set(value) {}
+
+    init {
+        x = ""
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneInheritedSecondary_mustBeInitializedWarning.kt

@@ -0,0 +1,13 @@
+// FIR_IDENTICAL
+// !LANGUAGE:-ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+open class Base(x: Int)
+class Foo : Base {
+    constructor() : super(1)
+    <!MUST_BE_INITIALIZED_WARNING!>var x: String<!>
+        set(value) {}
+
+    init {
+        x = ""
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedError.kt

@@ -0,0 +1,11 @@
+// FIR_IDENTICAL
+// !LANGUAGE:+ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+class Foo {
+    <!MUST_BE_INITIALIZED!>var x: String<!>
+        set(value) {}
+
+    constructor() {
+        x = ""
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedWarning.kt

@@ -0,0 +1,11 @@
+// FIR_IDENTICAL
+// !LANGUAGE:-ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+class Foo {
+    <!MUST_BE_INITIALIZED_WARNING!>var x: String<!>
+        set(value) {}
+
+    constructor() {
+        x = ""
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_mustBeInitializedError.kt

@@ -0,0 +1,12 @@
+// FIR_IDENTICAL
+// !LANGUAGE:+ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+class Foo {
+    constructor()
+    <!MUST_BE_INITIALIZED!>var x: String<!>
+        set(value) {}
+
+    init {
+        x = ""
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_mustBeInitializedWarning.kt

@@ -0,0 +1,12 @@
+// FIR_IDENTICAL
+// !LANGUAGE:-ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+class Foo {
+    constructor()
+    <!MUST_BE_INITIALIZED_WARNING!>var x: String<!>
+        set(value) {}
+
+    init {
+        x = ""
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValError_mustBeInitializedError.kt

@@ -0,0 +1,12 @@
+// FIR_IDENTICAL
+// !LANGUAGE:+ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor, +ProhibitOpenValDeferredInitialization
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+open class Foo {
+    constructor()
+
+    <!MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT!>open val x: String<!>
+
+    init {
+        x = ""
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValError_mustBeInitializedWarning.kt

@@ -0,0 +1,12 @@
+// FIR_IDENTICAL
+// !LANGUAGE:-ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor, +ProhibitOpenValDeferredInitialization
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+open class Foo {
+    constructor()
+
+    <!MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT_WARNING!>open val x: String<!>
+
+    init {
+        x = ""
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValWarning_mustBeInitializedError.kt

@@ -0,0 +1,12 @@
+// FIR_IDENTICAL
+// !LANGUAGE:+ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor, -ProhibitOpenValDeferredInitialization
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+open class Foo {
+    constructor()
+
+    <!MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT_WARNING!>open val x: String<!>
+
+    init {
+        x = ""
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValWarning_mustBeInitializedWarning.kt

@@ -0,0 +1,12 @@
+// FIR_IDENTICAL
+// !LANGUAGE:-ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor, -ProhibitOpenValDeferredInitialization
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+open class Foo {
+    constructor()
+
+    <!MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT_WARNING!>open val x: String<!>
+
+    init {
+        x = ""
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openVar_mustBeInitializedError.kt

@@ -0,0 +1,12 @@
+// FIR_IDENTICAL
+// !LANGUAGE:+ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+open class Foo {
+    constructor()
+
+    <!MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT!>open var x: String<!>
+
+    init {
+        x = ""
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openVar_mustBeInitializedWarning.kt

@@ -0,0 +1,12 @@
+// FIR_IDENTICAL
+// !LANGUAGE:-ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+open class Foo {
+    constructor()
+
+    <!MUST_BE_INITIALIZED_OR_FINAL_OR_ABSTRACT_WARNING!>open var x: String<!>
+
+    init {
+        x = ""
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_partialDeferredInitInSecondary_errorAnyway.kt

@@ -0,0 +1,13 @@
+// FIR_IDENTICAL
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+// !LANGUAGE:-ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor
+class Foo {
+    <!MUST_BE_INITIALIZED!>var foo: Int<!>
+        set(value) {}
+
+    constructor() {
+        if (1 != 1) {
+            foo = 1
+        }
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_partialDeferredInitInTwoSecondaries_errorAnyway.kt

@@ -0,0 +1,12 @@
+// FIR_IDENTICAL
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+// !LANGUAGE:-ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor
+class Foo {
+    <!MUST_BE_INITIALIZED!>var foo: Int<!>
+        set(value) {}
+
+    constructor(x: Int) {}
+    constructor() {
+        foo = 1
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_twoSecondary_mustBeInitializedError.kt

@@ -0,0 +1,13 @@
+// FIR_IDENTICAL
+// !LANGUAGE:+ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+class Foo {
+    constructor()
+    constructor(x: Int)
+    <!MUST_BE_INITIALIZED!>var x: String<!>
+        set(value) {}
+
+    init {
+        x = ""
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_twoSecondary_mustBeInitializedWarning.kt

@@ -0,0 +1,13 @@
+// FIR_IDENTICAL
+// !LANGUAGE:-ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+class Foo {
+    constructor()
+    constructor(x: Int)
+    <!MUST_BE_INITIALIZED_WARNING!>var x: String<!>
+        set(value) {}
+
+    init {
+        x = ""
+    }
+}

compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/onePrimary_oneSecondary_errorAnyway.kt

@@ -0,0 +1,13 @@
+// FIR_IDENTICAL
+// !LANGUAGE:-ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor
+// !DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+class Foo() {
+    constructor(x: Int) : this()
+
+    <!MUST_BE_INITIALIZED!>var x: String<!>
+        set(value) {}
+
+    init {
+        x = ""
+    }
+}

compiler/testData/diagnostics/tests/constructorConsistency/inspection.fir.kt

@@ -33,8 +33,8 @@ class SecondDerived : Second() {
     override fun foo() = y
 }
 
-open class Third {
-    open var x: String
+abstract class Third {
+    abstract var x: String
 
     constructor() {
         x = "X" // Non-final property access

compiler/testData/diagnostics/tests/constructorConsistency/inspection.kt

@@ -33,8 +33,8 @@ class SecondDerived : Second() {
     override fun foo() = y
 }
 
-open class Third {
-    open var x: String
+abstract class Third {
+    abstract var x: String
 
     constructor() {
         <!DEBUG_INFO_LEAKING_THIS!>x<!> = "X" // Non-final property access

compiler/testData/diagnostics/tests/constructorConsistency/inspection.txt

@@ -42,9 +42,9 @@ public final class SecondDerived : Second {
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public open class Third {
+public abstract class Third {
     public constructor Third()
-    public open var x: kotlin.String
+    public abstract var x: kotlin.String
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String

compiler/testData/diagnostics/tests/constructorConsistency/openProperty.fir.kt

@@ -1,7 +1,7 @@
-open class Base {
-    open var x: Int
+abstract class Base {
+    abstract var x: Int
 
-    open var y: Int
+    abstract var y: Int
 
     constructor() {
         x = 42
@@ -9,6 +9,5 @@ open class Base {
         val temp = this.x
         this.x = y
         y = temp
-
     }
 }

compiler/testData/diagnostics/tests/constructorConsistency/openProperty.kt

@@ -1,7 +1,7 @@
-open class Base {
-    open var x: Int
+abstract class Base {
+    abstract var x: Int
 
-    open var y: Int
+    abstract var y: Int
 
     constructor() {
         <!DEBUG_INFO_LEAKING_THIS!>x<!> = 42
@@ -9,6 +9,5 @@ open class Base {
         val temp = this.<!DEBUG_INFO_LEAKING_THIS!>x<!>
         this.<!DEBUG_INFO_LEAKING_THIS!>x<!> = <!DEBUG_INFO_LEAKING_THIS!>y<!>
         <!DEBUG_INFO_LEAKING_THIS!>y<!> = temp
-
     }
 }

compiler/testData/diagnostics/tests/constructorConsistency/openProperty.txt

@@ -1,9 +1,9 @@
 package
 
-public open class Base {
+public abstract class Base {
     public constructor Base()
-    public open var x: kotlin.Int
-    public open var y: kotlin.Int
+    public abstract var x: kotlin.Int
+    public abstract var y: kotlin.Int
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java

@@ -3043,6 +3043,124 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
             public void testVarDeferredInitInOpenClass() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/backingField/VarDeferredInitInOpenClass.kt");
             }
+
+            @Nested
+            @TestMetadata("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor")
+            @TestDataPath("$PROJECT_ROOT")
+            public class ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor {
+                @Test
+                public void testAllFilesPresentInProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor() throws Exception {
+                    KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor"), Pattern.compile("^(.*)\\.kts?$"), Pattern.compile("^(.+)\\.(reversed|fir|ll)\\.kts?$"), true);
+                }
+
+                @Test
+                @TestMetadata("implicitPrimaryConstructor_errorAnyway.kt")
+                public void testImplicitPrimaryConstructor_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/implicitPrimaryConstructor_errorAnyway.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneInheritedSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_oneInheritedSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneInheritedSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneInheritedSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneInheritedSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneInheritedSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_deferredInitInSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValError_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_openValError_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValError_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValError_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_openValError_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValError_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValWarning_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_openValWarning_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValWarning_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openValWarning_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_openValWarning_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openValWarning_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openVar_mustBeInitializedError.kt")
+                public void testNoPrimary_oneSecondary_openVar_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openVar_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_oneSecondary_openVar_mustBeInitializedWarning.kt")
+                public void testNoPrimary_oneSecondary_openVar_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_oneSecondary_openVar_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_partialDeferredInitInSecondary_errorAnyway.kt")
+                public void testNoPrimary_partialDeferredInitInSecondary_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_partialDeferredInitInSecondary_errorAnyway.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_partialDeferredInitInTwoSecondaries_errorAnyway.kt")
+                public void testNoPrimary_partialDeferredInitInTwoSecondaries_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_partialDeferredInitInTwoSecondaries_errorAnyway.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_twoSecondary_mustBeInitializedError.kt")
+                public void testNoPrimary_twoSecondary_mustBeInitializedError() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_twoSecondary_mustBeInitializedError.kt");
+                }
+
+                @Test
+                @TestMetadata("noPrimary_twoSecondary_mustBeInitializedWarning.kt")
+                public void testNoPrimary_twoSecondary_mustBeInitializedWarning() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/noPrimary_twoSecondary_mustBeInitializedWarning.kt");
+                }
+
+                @Test
+                @TestMetadata("onePrimary_oneSecondary_errorAnyway.kt")
+                public void testOnePrimary_oneSecondary_errorAnyway() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/backingField/prohibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor/onePrimary_oneSecondary_errorAnyway.kt");
+                }
+            }
         }
 
         @Nested

compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt

@@ -289,6 +289,7 @@ enum class LanguageFeature(
     KeepNullabilityWhenApproximatingLocalType(KOTLIN_2_0, kind = BUG_FIX), // KT-53982
     ProhibitAccessToInvisibleSetterFromDerivedClass(KOTLIN_2_0, kind = BUG_FIX), // KT-56662
     ProhibitOpenValDeferredInitialization(KOTLIN_2_0, kind = BUG_FIX), // KT-57553
+    ProhibitMissedMustBeInitializedWhenThereIsNoPrimaryConstructor(KOTLIN_2_0, kind = BUG_FIX), // KT-58472
 
     // 2.1