diff --git a/App/lib/core/Diag.vp b/App/lib/core/Diag.vp
index fe76b2b..9e0e307 100644
--- a/App/lib/core/Diag.vp
+++ b/App/lib/core/Diag.vp
@@ -39,7 +39,12 @@ define DIAG_MAX_FRAMES = 32   # 调用链上限（与 TypeGenMixin.TRACE_MAX 对
 # 用于"从错误发生点向外展示触发过程"。
 # 所有字符串都用 stdlib 深拷贝：编译期池会回绕，不能借用池内指针。
 class DiagEntry:
-    File: str              # 当前帧（错误点）文件
+    # 字段名不要与"本模块 import 的类名"重名：TPC 的类型/符号表按**非限定名**索引
+    # （Gen.structs / SymbolTable / _mangle_func_name），曾把本字段的 `File` 与
+    # `w32.fileio.File` 撞在一起，导致同模块 `fileio.File(...)` 的构造调用把
+    # `File.__before_init__` 的 self 形参解析成 `i8**`（llvmlite: "Type of #1 arg
+    # mismatch: i8** != %"...fileio.File"*"）。故此处用 FileName 而非 File。
+    FileName: str           # 当前帧（错误点）文件
     Line: int              # 当前帧行号
     ColStart: int          # caret 起始列（1-based；0 = 不画）
     ColEnd: int            # caret 结束列
@@ -68,7 +73,7 @@ def new_entry(max_frames: int) -> DiagEntry*:
     ent: DiagEntry* = (DiagEntry*)(stdlib.malloc(DiagEntry.__sizeof__()))
     if ent is None: return None
     if max_frames <= 0: max_frames = 1
-    ent.File = None
+    ent.FileName = None
     ent.Line = 0
     ent.ColStart = 0
     ent.ColEnd = 0
@@ -88,7 +93,7 @@ def begin(ent: DiagEntry*, category: str, msg: str, hint: str = None) -> int:
     ent.Category = dup_str(category)
     ent.Msg = dup_str(msg)
     ent.Hint = dup_str(hint)
-    ent.File = None
+    ent.FileName = None
     ent.Line = 0
     ent.ColStart = 0
     ent.ColEnd = 0
@@ -99,7 +104,7 @@ def begin(ent: DiagEntry*, category: str, msg: str, hint: str = None) -> int:
 # set_current - 设置当前帧（错误点）位置
 def set_current(ent: DiagEntry*, file_name: str, lineno: int, col_start: int, col_end: int) -> int:
     if ent is None: return 0
-    ent.File = dup_str(file_name)
+    ent.FileName = dup_str(file_name)
     ent.Line = lineno
     ent.ColStart = col_start
     ent.ColEnd = col_end
@@ -131,7 +136,7 @@ def emit(ent: DiagEntry*, direction: int) -> int:
             while i_u < ent.FrameCount:
                 emit_frame(str(ent.FrameFiles[i_u]), int(ent.FrameLines[i_u]))
                 i_u += 1
-    emit_current(ent.File, ent.Line, ent.ColStart, ent.ColEnd)
+    emit_current(ent.FileName, ent.Line, ent.ColStart, ent.ColEnd)
     emit_category(ent.Category, ent.Msg)
     return 0
 
@@ -139,7 +144,7 @@ def emit(ent: DiagEntry*, direction: int) -> int:
 # free_entry - 释放一条诊断（含深拷贝的字符串）
 def free_entry(ent: DiagEntry*) -> int:
     if ent is None: return 0
-    if ent.File is not None: stdlib.free(ent.File)
+    if ent.FileName is not None: stdlib.free(ent.FileName)
     if ent.Category is not None: stdlib.free(ent.Category)
     if ent.Msg is not None: stdlib.free(ent.Msg)
     if ent.Hint is not None: stdlib.free(ent.Hint)