feat: 枚举关联数据 ADT — enum Option { Some(i64), None }

src/sema/sema.c

@@ -346,6 +346,30 @@ static void analyze_enum_variant(AstNode* node, Scope* scope, ErrorList* errors,
         node->type.kind = TYPE_ERROR; return;
     }
     node->as.enum_variant.variant_index = vi;
+    // ADT: 检查 payload
+    TypeKind expected_pt = TYPE_VOID;
+    if (enum_sym->variant_payload_types)
+        expected_pt = enum_sym->variant_payload_types[vi];
+    if (node->as.enum_variant.payload) {
+        if (expected_pt == TYPE_VOID && enum_sym->variant_payload_types) {
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
+                      "枚举变体 '%s::%s' 不接受 payload",
+                      node->as.enum_variant.enum_name, node->as.enum_variant.variant_name);
+            node->type.kind = TYPE_ERROR; return;
+        }
+        analyze_expr(node->as.enum_variant.payload, scope, errors, a);
+        TypeKind actual = node->as.enum_variant.payload->type.kind;
+        if (actual != TYPE_ERROR && actual != expected_pt) {
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
+                      "枚举变体 payload 类型不匹配: 期望 '%s'，得到 '%s'",
+                      type_name(expected_pt), type_name(actual));
+        }
+    } else if (expected_pt != TYPE_VOID) {
+        error_add(errors, "<sema>", node->loc.line, node->loc.col,
+                  "枚举变体 '%s::%s' 需要 payload 类型 '%s'",
+                  node->as.enum_variant.enum_name, node->as.enum_variant.variant_name,
+                  type_name(expected_pt));
+    }
     node->type.kind = TYPE_ENUM;
 }
 
@@ -451,6 +475,8 @@ static void analyze_node(AstNode* node, Scope* scope, ErrorList* errors, Arena*
             AstNode* ed = node->as.program.enums[i];
             scope_insert_enum(scope, a, ed->as.enum_decl.name,
                               ed->as.enum_decl.variants,
+                              ed->as.enum_decl.variant_payload_types,
+                              ed->as.enum_decl.variant_payload_struct_names,
                               ed->as.enum_decl.variant_count);
         }
         // 第一遍：收集所有结构体定义

src/sema/symbol.c

@@ -35,6 +35,8 @@ Symbol* scope_insert(Scope* scope, void* alloc, const char* name,
     sym->struct_field_types = NULL;
     sym->struct_field_count = 0;
     sym->struct_type_name = NULL;
+    sym->variant_payload_types = NULL;
+    sym->variant_payload_struct_names = NULL;
     sym->array_element_type = 0;
     sym->array_element_struct_name = NULL;
     sym->array_size = 0;
@@ -66,6 +68,8 @@ Symbol* scope_insert_function(Scope* scope, void* alloc, const char* name,
     sym->struct_field_types = NULL;
     sym->struct_field_count = 0;
     sym->struct_type_name = NULL;
+    sym->variant_payload_types = NULL;
+    sym->variant_payload_struct_names = NULL;
     sym->array_element_type = 0;
     sym->array_element_struct_name = NULL;
     sym->array_size = 0;
@@ -93,6 +97,8 @@ Symbol* scope_insert_struct(Scope* scope, void* alloc, const char* name,
     sym->struct_field_struct_names = fstruct_names;
     sym->struct_field_count = fc;
     sym->struct_type_name = NULL;
+    sym->variant_payload_types = NULL;
+    sym->variant_payload_struct_names = NULL;
     sym->array_element_type = 0;
     sym->array_element_struct_name = NULL;
     sym->array_size = 0;
@@ -122,7 +128,8 @@ int scope_struct_field_index(const Symbol* sym, const char* field_name) {
 }
 
 Symbol* scope_insert_enum(Scope* scope, void* alloc, const char* name,
-                           const char** vnames, size_t vc) {
+                           const char** vnames, TypeKind* ptypes,
+                           const char** pstruct_names, size_t vc) {
     if (scope->head) {
         for (Symbol* sym = scope->head; sym; sym = sym->next) {
             if (strcmp(sym->name, name) == 0) return NULL;
@@ -138,6 +145,8 @@ Symbol* scope_insert_enum(Scope* scope, void* alloc, const char* name,
     sym->struct_field_struct_names = NULL;
     sym->struct_field_count = vc;
     sym->struct_type_name = NULL;
+    sym->variant_payload_types = ptypes;
+    sym->variant_payload_struct_names = pstruct_names;
     sym->array_element_type = 0;
     sym->array_element_struct_name = NULL;
     sym->array_size = 0;

src/sema/symbol.h

@@ -29,6 +29,9 @@ typedef struct Symbol {
     TypeKind    array_element_type;
     const char* array_element_struct_name;
     int64_t     array_size;
+    // 枚举特有（ADT payload）
+    TypeKind*    variant_payload_types;
+    const char** variant_payload_struct_names;
     // 类型别名标记
     bool         is_type_alias;
     // 链表（同一作用域内的下一个符号）
@@ -69,7 +72,8 @@ int scope_struct_field_index(const Symbol* sym, const char* field_name);
 
 // 插入枚举符号
 Symbol* scope_insert_enum(Scope* scope, void* alloc, const char* name,
-                           const char** vnames, size_t vc);
+                           const char** vnames, TypeKind* ptypes,
+                           const char** pstruct_names, size_t vc);
 
 // 在枚举符号中查找变体索引（返回 -1 表示未找到）
 int scope_enum_variant_index(const Symbol* sym, const char* variant_name);