diff --git a/src/CompilerBase.php b/src/CompilerBase.php
index 8ac98b30..2b0ac4d5 100644
--- a/src/CompilerBase.php
+++ b/src/CompilerBase.php
@@ -2382,7 +2382,12 @@ class CompilerBase implements PropertyAccessContext
         return $this->getNativeName($method, $classDef->namespace, $classDef->name);
     }
 
-    protected function findNativeClassConst(NodeAbstract $expr, string $class, string $const): string|false
+    protected function findNativeClassConst(
+        NodeAbstract $expr,
+        string $class,
+        string $const,
+        ?string $accessingClass = null
+    ): string|false
     {
         if (!$this->hasClass($class)) {
             return false;
@@ -2426,7 +2431,12 @@ class CompilerBase implements PropertyAccessContext
         if ($constDef === null) {
             return false;
         }
-        if ($classDef instanceof ClassDef && !$this->checkAccessible($classDef, $constDef->flags)) {
+        if ($classDef instanceof ClassDef
+            && !$this->checkAccessibleByClassName(
+                $classDef->getNamespacedName(false),
+                $constDef->flags,
+                $accessingClass,
+            )) {
             $this->fatalError($expr, 'Constant `' . $classDef->getNamespacedName() . '::' . $const . '` is not accessible');
         }
         if ($constDef->type === Type::ARRAY) {
@@ -3869,13 +3879,24 @@ class CompilerBase implements PropertyAccessContext
         return $this->checkAccessibleByClassName($classDef->getNamespacedName(false), $flags);
     }
 
-    protected function checkAccessibleByClassName(string $declaringClass, int $flags): bool
+    protected function checkAccessibleByClassName(
+        string $declaringClass,
+        int $flags,
+        ?string $accessingClass = null
+    ): bool
     {
-        $scopeClassDef = $this->classDef;
-        if ($this->functionDef !== null
-            && $this->functionDef->attributeFactoryScope !== ''
-            && $this->hasClass($this->functionDef->attributeFactoryScope)) {
-            $scopeClassDef = $this->getClass($this->functionDef->attributeFactoryScope);
+        if ($accessingClass !== null) {
+            $accessingClass = ltrim($accessingClass, '\\');
+            $scopeClassDef = $this->hasClass($accessingClass)
+                ? $this->getClass($accessingClass)
+                : null;
+        } else {
+            $scopeClassDef = $this->classDef;
+            if ($this->functionDef !== null
+                && $this->functionDef->attributeFactoryScope !== ''
+                && $this->hasClass($this->functionDef->attributeFactoryScope)) {
+                $scopeClassDef = $this->getClass($this->functionDef->attributeFactoryScope);
+            }
         }
         // 私有方法，只能当前的类使用
         if ($flags & Modifiers::PRIVATE) {
diff --git a/src/Generator/CallArgumentGenerator.php b/src/Generator/CallArgumentGenerator.php
index 826516eb..8fd214b4 100644
--- a/src/Generator/CallArgumentGenerator.php
+++ b/src/Generator/CallArgumentGenerator.php
@@ -65,7 +65,7 @@ trait CallArgumentGenerator
                     continue;
                 }
                 if (!isset($args[$k])) {
-                    if ($argInfo->defaultValue === null) {
+                    if ($argInfo->default === '') {
                         $errorNode = null;
                         foreach ($callArgs as $a) {
                             if ($a instanceof Node\Arg && $a->name) {
@@ -76,7 +76,10 @@ trait CallArgumentGenerator
                         $argName = $argInfo->phpName ?: $this->unescapeVarName($argInfo->name);
                         $this->fatalError($errorNode ?? reset($callArgs), 'Named argument `' . $argName . '` is missing default value');
                     }
-                    $args[$k] = new Node\Arg($argInfo->defaultValue);
+                    // Defaults are resolved in the declaration scope. Re-parsing
+                    // the original AST here would evaluate self/parent/private
+                    // class constants in the caller's scope instead.
+                    $args[$k] = $this->genDefaultArgumentExpr($nativeFunc, $k);
                 }
             }
             ksort($args);
diff --git a/src/Resolver/ClassConstantValueTrait.php b/src/Resolver/ClassConstantValueTrait.php
index a674fd7a..90ec17e5 100644
--- a/src/Resolver/ClassConstantValueTrait.php
+++ b/src/Resolver/ClassConstantValueTrait.php
@@ -27,7 +27,12 @@ trait ClassConstantValueTrait
             $namespace = $this->getNamespaceOfClass($currentClass);
         }
         $class = $this->getNamespacedClassName($_class, $namespace);
-        $nativeConst = $this->findNativeClassConst($expr, $class, $name);
+        $nativeConst = $this->findNativeClassConst(
+            $expr,
+            $class,
+            $name,
+            $currentClass !== '' ? $currentClass : null,
+        );
         if ($nativeConst and $expr->hasAttribute('nativeConst')) {
             $constDef = $expr->getAttribute('nativeConst');
             if ($constDef->valueExpr !== null) {
diff --git a/src/gen_stub.php b/src/gen_stub.php
index 1725b61d..e2cb90e8 100755
--- a/src/gen_stub.php
+++ b/src/gen_stub.php
@@ -5121,7 +5121,12 @@ function parseFunctionLike(
             }
 
             if ($param->default instanceof Expr\ClassConstFetch && $param->default->class->toLowerString() === "self") {
-                $defaultValue = getTranslator()->getClassConstValue($func, $name->className->name, $param->default->name->name);
+                $defaultValue = getTranslator()->getClassConstValue(
+                    $func,
+                    $name->className->name,
+                    $param->default->name->name,
+                    ClassInfo::$currentClass,
+                );
                 $defaultValue = var_export($defaultValue, true);
             } elseif ($param->default instanceof String_) {
                 // Keep this as a PHP expression. ArgInfo escapes the expression
diff --git a/tests/compiler/const/private-class-const-param-default.phpt b/tests/compiler/const/private-class-const-param-default.phpt
new file mode 100644
index 00000000..4c3786c5
--- /dev/null
+++ b/tests/compiler/const/private-class-const-param-default.phpt
@@ -0,0 +1,54 @@
+--TEST--
+Private and protected class constants are valid method parameter defaults in declaration scope
+--FILE--
+<?php
+
+class PrivateConstDefaults
+{
+    private const VALUE = 42;
+    private const LABEL = 'private';
+
+    public function show(
+        int $value = self::VALUE,
+        string $label = PrivateConstDefaults::LABEL,
+        string $suffix = 'default',
+    ): void {
+        var_dump($value, $label, $suffix);
+    }
+}
+
+class ProtectedConstParent
+{
+    protected const VALUE = 7;
+}
+
+class ProtectedConstChild extends ProtectedConstParent
+{
+    public function show(int $value = parent::VALUE, string $suffix = 'default'): void
+    {
+        var_dump($value, $suffix);
+    }
+}
+
+function main(): void
+{
+    $private = new PrivateConstDefaults();
+    $private->show();
+    $private->show(suffix: 'named');
+
+    $protected = new ProtectedConstChild();
+    $protected->show();
+    $protected->show(suffix: 'named');
+}
+?>
+--EXPECT--
+int(42)
+string(7) "private"
+string(7) "default"
+int(42)
+string(7) "private"
+string(5) "named"
+int(7)
+string(7) "default"
+int(7)
+string(5) "named"