[FIR] Implement IMPLICIT_NOTHING_*_TYPE diagnostics

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

@@ -1927,6 +1927,18 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.IMPLICIT_NOTHING_RETURN_TYPE) { firDiagnostic ->
+        ImplicitNothingReturnTypeImpl(
+            firDiagnostic as KtPsiDiagnostic,
+            token,
+        )
+    }
+    add(FirErrors.IMPLICIT_NOTHING_PROPERTY_TYPE) { firDiagnostic ->
+        ImplicitNothingPropertyTypeImpl(
+            firDiagnostic as KtPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.CYCLIC_GENERIC_UPPER_BOUND) { firDiagnostic ->
         CyclicGenericUpperBoundImpl(
             firDiagnostic as KtPsiDiagnostic,

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

@@ -1371,6 +1371,14 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         abstract val isMismatchDueToNullability: Boolean
     }
 
+    abstract class ImplicitNothingReturnType : KtFirDiagnostic<PsiElement>() {
+        override val diagnosticClass get() = ImplicitNothingReturnType::class
+    }
+
+    abstract class ImplicitNothingPropertyType : KtFirDiagnostic<PsiElement>() {
+        override val diagnosticClass get() = ImplicitNothingPropertyType::class
+    }
+
     abstract class CyclicGenericUpperBound : KtFirDiagnostic<PsiElement>() {
         override val diagnosticClass get() = CyclicGenericUpperBound::class
     }

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

@@ -1648,6 +1648,16 @@ internal class ReturnTypeMismatchImpl(
     override val token: KtLifetimeToken,
 ) : KtFirDiagnostic.ReturnTypeMismatch(), KtAbstractFirDiagnostic<KtExpression>
 
+internal class ImplicitNothingReturnTypeImpl(
+    override val firDiagnostic: KtPsiDiagnostic,
+    override val token: KtLifetimeToken,
+) : KtFirDiagnostic.ImplicitNothingReturnType(), KtAbstractFirDiagnostic<PsiElement>
+
+internal class ImplicitNothingPropertyTypeImpl(
+    override val firDiagnostic: KtPsiDiagnostic,
+    override val token: KtLifetimeToken,
+) : KtFirDiagnostic.ImplicitNothingPropertyType(), KtAbstractFirDiagnostic<PsiElement>
+
 internal class CyclicGenericUpperBoundImpl(
     override val firDiagnostic: KtPsiDiagnostic,
     override val token: KtLifetimeToken,