[FIR] Implement PACKAGE_OR_CLASSIFIER_REDECLARATION

Fix REDECLARATION positioning

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

@@ -1929,6 +1929,15 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.PACKAGE_OR_CLASSIFIER_REDECLARATION) { firDiagnostic ->
+        PackageOrClassifierRedeclarationImpl(
+            firDiagnostic.a.map { firBasedSymbol ->
+                firSymbolBuilder.buildSymbol(firBasedSymbol.fir)
+            },
+            firDiagnostic as FirPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.METHOD_OF_ANY_IMPLEMENTED_IN_INTERFACE) { firDiagnostic ->
         MethodOfAnyImplementedInInterfaceImpl(
             firDiagnostic as FirPsiDiagnostic,

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

@@ -1369,11 +1369,16 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         abstract val conflictingOverloads: List<KtSymbol>
     }
 
-    abstract class Redeclaration : KtFirDiagnostic<PsiElement>() {
+    abstract class Redeclaration : KtFirDiagnostic<KtNamedDeclaration>() {
         override val diagnosticClass get() = Redeclaration::class
         abstract val conflictingDeclarations: List<KtSymbol>
     }
 
+    abstract class PackageOrClassifierRedeclaration : KtFirDiagnostic<KtNamedDeclaration>() {
+        override val diagnosticClass get() = PackageOrClassifierRedeclaration::class
+        abstract val conflictingDeclarations: List<KtSymbol>
+    }
+
     abstract class MethodOfAnyImplementedInInterface : KtFirDiagnostic<PsiElement>() {
         override val diagnosticClass get() = MethodOfAnyImplementedInInterface::class
     }

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

@@ -2187,7 +2187,15 @@ internal class RedeclarationImpl(
     override val conflictingDeclarations: List<KtSymbol>,
     firDiagnostic: FirPsiDiagnostic,
     override val token: ValidityToken,
-) : KtFirDiagnostic.Redeclaration(), KtAbstractFirDiagnostic<PsiElement> {
+) : KtFirDiagnostic.Redeclaration(), KtAbstractFirDiagnostic<KtNamedDeclaration> {
+    override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
+}
+
+internal class PackageOrClassifierRedeclarationImpl(
+    override val conflictingDeclarations: List<KtSymbol>,
+    firDiagnostic: FirPsiDiagnostic,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.PackageOrClassifierRedeclaration(), KtAbstractFirDiagnostic<KtNamedDeclaration> {
     override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
 }