feat(match): 重名 case 标签 fail-fast
MatchGenMixin._translate_match_impl 新增前置检查（任何 IR 产出之前）：新增 _case_label_same / _value_label_same 比较 switch 标签（常量 / 名字 / 属性链 / MatchSingleton / MatchClass 变体名 / MatchOr 子模式），标签重复或出现多个 `case _` 时 fatal_error 终止（C switch 不允许重复 case 标签）。
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@@ -90,6 +90,38 @@ novirtual class MatchGenMixin:
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m_node: ast.Match* = ast.Match*(node)
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# 重名 case 检测（fail-fast）：C 的 switch 不允许重复 case 标签（重复标签让
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# 某个臂永远不可达，且常意味着漏改的分支）；`case _`（default）只允许一个。
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# 在任何 IR 产出之前检查，保证报错即终止。
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cases_chk: list[ast.AST*]* = m_node.cases
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if cases_chk is not None:
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ccn: sizet = len(cases_chk)
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default_cnt: int = 0
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dci: int = 0
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while dci < ccn:
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dcase: ast.AST* = cases_chk.get(dci)
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if dcase is not None and dcase.kind() == ast.ASTKind.MatchCase:
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dpat: ast.AST* = rawptr[ast.MatchCase](dcase).pattern
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if dpat is not None:
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if dpat.kind() == ast.ASTKind.MatchAs \
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and rawptr[ast.MatchAs](dpat).pattern is None:
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default_cnt = default_cnt + 1
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else:
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dcj: int = dci + 1
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while dcj < ccn:
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dcase2: ast.AST* = cases_chk.get(dcj)
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if dcase2 is not None and dcase2.kind() == ast.ASTKind.MatchCase:
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dpat2: ast.AST* = rawptr[ast.MatchCase](dcase2).pattern
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if self._case_label_same(dpat, dpat2) != 0:
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self.Gen.TypeGenErr.fatal_error(dcase2,
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f"match 出现重名 case：第 {dci} 与第 {dcj} 个 case 的标签相同（C switch 不允许重复 case 标签）",
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"SyntaxError")
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dcj = dcj + 1
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dci = dci + 1
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if default_cnt > 1:
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self.Gen.TypeGenErr.fatal_error(node,
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f"match 出现 {default_cnt} 个 `case _`（default 只允许一个）", "SyntaxError")
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# 1. 求值 subject
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subject_node: ast.AST* = m_node.subject
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if subject_node is None:
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@@ -214,6 +246,87 @@ novirtual class MatchGenMixin:
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return None
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return self.Gen.ClassGenEnum._lookup_renum_variant(variant_name)
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# ============================================================
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# _value_label_same / _case_label_same - 重名 case 判定（switch 标签比较）
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#
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# C 的 switch 不允许重复 case 标签：重复标签会让某个臂永远不可达，且通常
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# 意味着漏改的分支。只比较 switch 标签本身：
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# MatchValue（常量 / 名字 / 属性链）、MatchSingleton(None)、MatchClass（变体名）；
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# MatchOr 逐个子模式两两比较；MatchAs / MatchSequence 无 switch 标签，恒不等。
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# ============================================================
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def _value_label_same(self, a: ast.AST*, b: ast.AST*) -> int:
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"""两个 `case` 值节点是否等价（常量值 / 名字 / 属性链）"""
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if a is None or b is None:
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return 0
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ka: int = a.kind()
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if ka != b.kind():
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return 0
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if ka == ast.ASTKind.Constant:
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ca: ast.Constant* = ast.Constant*(a)
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cb: ast.Constant* = ast.Constant*(b)
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if ca.const_kind != cb.const_kind:
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return 0
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if ca.const_kind == ast.CONST_STR:
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if ca.str_val is not None and cb.str_val is not None \
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and string.strcmp(ca.str_val, cb.str_val) == 0:
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return 1
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return 0
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if ca.const_kind == ast.CONST_FLOAT:
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if ca.float_val == cb.float_val:
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return 1
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return 0
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# 整数 / 布尔 / 字符码
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if ca.int_val == cb.int_val:
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return 1
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return 0
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if ka == ast.ASTKind.Name:
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na: ast.Name* = ast.Name*(a)
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nb: ast.Name* = ast.Name*(b)
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if na.id is not None and nb.id is not None and string.strcmp(na.id, nb.id) == 0:
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return 1
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return 0
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if ka == ast.ASTKind.Attribute:
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aa: ast.Attribute* = ast.Attribute*(a)
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ab: ast.Attribute* = ast.Attribute*(b)
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if aa.attr is None or ab.attr is None or string.strcmp(aa.attr, ab.attr) != 0:
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return 0
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return self._value_label_same(aa.value, ab.value)
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return 0
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def _case_label_same(self, a: ast.AST*, b: ast.AST*) -> int:
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"""两个 case 模式是否有相同的 switch 标签"""
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if a is None or b is None:
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return 0
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ka: int = a.kind()
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if ka != b.kind():
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return 0
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if ka == ast.ASTKind.MatchValue:
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av: ast.AST* = rawptr[ast.MatchValue](a).value
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bv: ast.AST* = rawptr[ast.MatchValue](b).value
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return self._value_label_same(av, bv)
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if ka == ast.ASTKind.MatchSingleton:
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return 1 # MatchSingleton 只可能是 None
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if ka == ast.ASTKind.MatchClass:
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an: str = self._extract_variant_name_from_cls(a)
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bn: str = self._extract_variant_name_from_cls(b)
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if an is None or bn is None:
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return 0
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if string.strcmp(an, bn) == 0:
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return 1
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return 0
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if ka == ast.ASTKind.MatchOr:
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ap: list[ast.AST*]* = rawptr[ast.MatchOr](a).patterns
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bp: list[ast.AST*]* = rawptr[ast.MatchOr](b).patterns
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if ap is None or bp is None or len(ap) != len(bp):
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return 0
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oi: int = 0
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while oi < len(ap):
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if self._case_label_same(ap.get(oi), bp.get(oi)) == 0:
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return 0
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oi = oi + 1
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return 1
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return 0
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# ============================================================
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# _has_no_break - 检测 case body 是否要求 fallthrough（落到下一个 case）
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#
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