FIR checker: report violations related to API mode

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

@@ -1199,6 +1199,30 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.NO_EXPLICIT_VISIBILITY_IN_API_MODE) { firDiagnostic ->
+        NoExplicitVisibilityInApiModeImpl(
+            firDiagnostic as FirPsiDiagnostic,
+            token,
+        )
+    }
+    add(FirErrors.NO_EXPLICIT_VISIBILITY_IN_API_MODE_WARNING) { firDiagnostic ->
+        NoExplicitVisibilityInApiModeWarningImpl(
+            firDiagnostic as FirPsiDiagnostic,
+            token,
+        )
+    }
+    add(FirErrors.NO_EXPLICIT_RETURN_TYPE_IN_API_MODE) { firDiagnostic ->
+        NoExplicitReturnTypeInApiModeImpl(
+            firDiagnostic as FirPsiDiagnostic,
+            token,
+        )
+    }
+    add(FirErrors.NO_EXPLICIT_RETURN_TYPE_IN_API_MODE_WARNING) { firDiagnostic ->
+        NoExplicitReturnTypeInApiModeWarningImpl(
+            firDiagnostic as FirPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.INLINE_CLASS_NOT_TOP_LEVEL) { firDiagnostic ->
         InlineClassNotTopLevelImpl(
             firDiagnostic as FirPsiDiagnostic,

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

@@ -867,6 +867,22 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         abstract val message: String
     }
 
+    abstract class NoExplicitVisibilityInApiMode : KtFirDiagnostic<KtDeclaration>() {
+        override val diagnosticClass get() = NoExplicitVisibilityInApiMode::class
+    }
+
+    abstract class NoExplicitVisibilityInApiModeWarning : KtFirDiagnostic<KtDeclaration>() {
+        override val diagnosticClass get() = NoExplicitVisibilityInApiModeWarning::class
+    }
+
+    abstract class NoExplicitReturnTypeInApiMode : KtFirDiagnostic<KtDeclaration>() {
+        override val diagnosticClass get() = NoExplicitReturnTypeInApiMode::class
+    }
+
+    abstract class NoExplicitReturnTypeInApiModeWarning : KtFirDiagnostic<KtDeclaration>() {
+        override val diagnosticClass get() = NoExplicitReturnTypeInApiModeWarning::class
+    }
+
     abstract class InlineClassNotTopLevel : KtFirDiagnostic<KtDeclaration>() {
         override val diagnosticClass get() = InlineClassNotTopLevel::class
     }

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

@@ -1036,6 +1036,26 @@ internal class InapplicableOperatorModifierImpl(
     override val token: ValidityToken,
 ) : KtFirDiagnostic.InapplicableOperatorModifier(), KtAbstractFirDiagnostic<PsiElement>
 
+internal class NoExplicitVisibilityInApiModeImpl(
+    override val firDiagnostic: FirPsiDiagnostic,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.NoExplicitVisibilityInApiMode(), KtAbstractFirDiagnostic<KtDeclaration>
+
+internal class NoExplicitVisibilityInApiModeWarningImpl(
+    override val firDiagnostic: FirPsiDiagnostic,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.NoExplicitVisibilityInApiModeWarning(), KtAbstractFirDiagnostic<KtDeclaration>
+
+internal class NoExplicitReturnTypeInApiModeImpl(
+    override val firDiagnostic: FirPsiDiagnostic,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.NoExplicitReturnTypeInApiMode(), KtAbstractFirDiagnostic<KtDeclaration>
+
+internal class NoExplicitReturnTypeInApiModeWarningImpl(
+    override val firDiagnostic: FirPsiDiagnostic,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.NoExplicitReturnTypeInApiModeWarning(), KtAbstractFirDiagnostic<KtDeclaration>
+
 internal class InlineClassNotTopLevelImpl(
     override val firDiagnostic: FirPsiDiagnostic,
     override val token: ValidityToken,