diff --git a/lib/core/Handles/HandlesExprCall.py b/lib/core/Handles/HandlesExprCall.py
index a7c4f73..efa2429 100644
--- a/lib/core/Handles/HandlesExprCall.py
+++ b/lib/core/Handles/HandlesExprCall.py
@@ -3019,12 +3019,14 @@ class ExprCallHandle(BaseHandle):
         cached = spec_cache.get(spec_key)
         if not isinstance(cached, tuple) or len(cached) < 2:
             # 缓存中还没有该特化：直接从头生成完整特化（方法体随类特化一起产出）
+            _TypeArgs: list[str] = ClassName[len(base_name) + 1:-1].split('][')
+            _TypeNames: list[str] = [a.rsplit('.', 1)[-1] for a in _TypeArgs]
             try:
                 self.Trans.ClassHandler._specialize_generic_class(
-                    base_name, ClassName[len(base_name) + 1:-1].split(']['),
-                    Gen, declare_only=False)
-            except Exception:
-                pass
+                    base_name, _TypeArgs, Gen,
+                    type_names=_TypeNames, declare_only=False)
+            except Exception as _spec_err:
+                Gen._generic_spec_error = f'{type(_spec_err).__name__}: {_spec_err}'
             return
         cached_name: str = cached[0]
         was_declare_only: bool = cached[1]
@@ -3944,7 +3946,11 @@ class ExprCallHandle(BaseHandle):
                 self._append_eh_msg_out_arg(call_args_fb, func, Gen)
                 adjusted = Gen._adjust_args(call_args_fb, func)
                 return Gen.builder.call(func, adjusted, name=f"call_{BareFuncName}")
-        raise Exception(f"Undefined method '{MethodName}' in class '{ClassName}' (no function declaration found for '{FullMethodName}')")
+        _spec_diag: str = getattr(Gen, '_generic_spec_error', '')
+        raise Exception(
+            f"Undefined method '{MethodName}' in class '{ClassName}' "
+            f"(no function declaration found for '{FullMethodName}')"
+            + (f"；泛型特化失败: {_spec_diag}" if _spec_diag else ""))
 
     def _EnsureReceiverStructConcrete(self, ClassName: str, class_sha1: str | None, ObjVal: Any, Gen: "LlvmGeneratorMixin") -> Any:
         """根本修复：vtable 分派前保证接收者 struct 已具化（非 opaque）。