feat: struct参数/返回值 + SourceLoc + 测试补全

- struct 可作函数参数和返回值 (fn make_point -> Point)
- SourceLoc 抽象: 所有 ast_make_* 参数 + AstNode 迁移完毕
- sema: +4 struct 类型检查测试 (字段类型/未定义/数量/嵌套)
- codegen: +2 struct IR 生成测试 (decl + field_access)
- 新增集成测试 14_struct_fn.l

测试: 104 单元 + 14 集成 = 全部通过

include/l_lang.h

@@ -29,6 +29,17 @@ static inline const char* type_name(TypeKind kind) {
     }
 }
 
+// === 源码位置（替代分散的 line/col 参数）===
+typedef struct {
+    int line;
+    int col;
+} SourceLoc;
+
+// 手动创建 SourceLoc
+static inline SourceLoc loc_at(int line, int col) {
+    return (SourceLoc){ .line = line, .col = col };
+}
+
 // === 向前声明 ===
 typedef struct Token Token;
 typedef struct AstNode AstNode;

src/ast/ast.c

@@ -6,10 +6,10 @@
     AstNode* n = (AstNode*)arena_alloc_impl(alloc, sizeof(AstNode)); \
     if (!n) return NULL; \
     n->kind = (k); n->type.kind = TYPE_UNKNOWN; n->type.struct_name = NULL; \
-    n->line = line; n->col = col
+    n->loc = loc
 
 AstNode* ast_make_program(void* alloc, AstNode** fns, size_t fn_count,
-                          AstNode** structs, size_t struct_count, int line, int col) {
+                          AstNode** structs, size_t struct_count, SourceLoc loc) {
     NEW(alloc, AST_PROGRAM);
     n->as.program.functions = fns;
     n->as.program.fn_count = fn_count;
@@ -19,30 +19,31 @@ AstNode* ast_make_program(void* alloc, AstNode** fns, size_t fn_count,
 }
 
 AstNode* ast_make_function(void* alloc, const char* name, AstNode** params, size_t pcount,
-                           TypeKind ret, AstNode* body, int line, int col) {
+                           TypeKind ret, const char* ret_struct_name, AstNode* body, SourceLoc loc) {
     NEW(alloc, AST_FUNCTION);
     n->as.function.name = name; n->as.function.params = params;
     n->as.function.param_count = pcount; n->as.function.return_type = ret;
+    n->as.function.return_struct_type_name = ret_struct_name;
     n->as.function.body = body;
     return n;
 }
 
 AstNode* ast_make_parameter(void* alloc, const char* name, TypeKind type,
-                             const char* struct_type_name, int line, int col) {
+                             const char* struct_type_name, SourceLoc loc) {
     NEW(alloc, AST_PARAMETER);
     n->as.parameter.name = name; n->as.parameter.type = type;
     n->as.parameter.struct_type_name = struct_type_name;
     return n;
 }
 
-AstNode* ast_make_block(void* alloc, AstNode** stmts, size_t count, int line, int col) {
+AstNode* ast_make_block(void* alloc, AstNode** stmts, size_t count, SourceLoc loc) {
     NEW(alloc, AST_BLOCK);
     n->as.block.stmts = stmts; n->as.block.stmt_count = count;
     return n;
 }
 
 AstNode* ast_make_let(void* alloc, const char* name, TypeKind annot_type, bool has_type_annot,
-                      bool is_mut, AstNode* init, const char* struct_type_name, int line, int col) {
+                      bool is_mut, AstNode* init, const char* struct_type_name, SourceLoc loc) {
     NEW(alloc, AST_LET_STMT);
     n->as.let_stmt.name = name; n->as.let_stmt.annot_type = annot_type;
     n->as.let_stmt.has_type_annot = has_type_annot; n->as.let_stmt.is_mut = is_mut;
@@ -51,84 +52,84 @@ AstNode* ast_make_let(void* alloc, const char* name, TypeKind annot_type, bool h
     return n;
 }
 
-AstNode* ast_make_assign(void* alloc, const char* name, AstNode* value, int line, int col) {
+AstNode* ast_make_assign(void* alloc, const char* name, AstNode* value, SourceLoc loc) {
     NEW(alloc, AST_ASSIGN_STMT);
     n->as.assign_stmt.name = name; n->as.assign_stmt.value = value;
     return n;
 }
 
-AstNode* ast_make_if(void* alloc, AstNode* cond, AstNode* then_b, AstNode* else_b, int line, int col) {
+AstNode* ast_make_if(void* alloc, AstNode* cond, AstNode* then_b, AstNode* else_b, SourceLoc loc) {
     NEW(alloc, AST_IF_STMT);
     n->as.if_stmt.cond = cond; n->as.if_stmt.then_block = then_b;
     n->as.if_stmt.else_block = else_b;
     return n;
 }
 
-AstNode* ast_make_while(void* alloc, AstNode* cond, AstNode* body, int line, int col) {
+AstNode* ast_make_while(void* alloc, AstNode* cond, AstNode* body, SourceLoc loc) {
     NEW(alloc, AST_WHILE_STMT);
     n->as.while_stmt.cond = cond; n->as.while_stmt.body = body;
     return n;
 }
 
-AstNode* ast_make_return(void* alloc, AstNode* expr, int line, int col) {
+AstNode* ast_make_return(void* alloc, AstNode* expr, SourceLoc loc) {
     NEW(alloc, AST_RETURN_STMT);
     n->as.return_stmt.expr = expr;
     return n;
 }
 
-AstNode* ast_make_expr_stmt(void* alloc, AstNode* expr, int line, int col) {
+AstNode* ast_make_expr_stmt(void* alloc, AstNode* expr, SourceLoc loc) {
     NEW(alloc, AST_EXPR_STMT);
     n->as.expr_stmt.expr = expr;
     return n;
 }
 
-AstNode* ast_make_binary(void* alloc, BinaryOp op, AstNode* left, AstNode* right, int line, int col) {
+AstNode* ast_make_binary(void* alloc, BinaryOp op, AstNode* left, AstNode* right, SourceLoc loc) {
     NEW(alloc, AST_BINARY_EXPR);
     n->as.binary.op = op; n->as.binary.left = left; n->as.binary.right = right;
     return n;
 }
 
-AstNode* ast_make_unary(void* alloc, BinaryOp op, AstNode* operand, int line, int col) {
+AstNode* ast_make_unary(void* alloc, BinaryOp op, AstNode* operand, SourceLoc loc) {
     NEW(alloc, AST_UNARY_EXPR);
     n->as.unary.op = op; n->as.unary.operand = operand;
     return n;
 }
 
-AstNode* ast_make_call(void* alloc, const char* name, AstNode** args, size_t count, int line, int col) {
+AstNode* ast_make_call(void* alloc, const char* name, AstNode** args, size_t count, SourceLoc loc) {
     NEW(alloc, AST_CALL_EXPR);
     n->as.call.name = name; n->as.call.args = args; n->as.call.arg_count = count;
     return n;
 }
 
-AstNode* ast_make_literal_i64(void* alloc, int64_t val, int line, int col) {
+AstNode* ast_make_literal_i64(void* alloc, int64_t val, SourceLoc loc) {
     NEW(alloc, AST_LITERAL_EXPR);
     n->as.literal.lit_type = TYPE_I64; n->as.literal.i64_val = val;
     n->type.kind = TYPE_I64;
     return n;
 }
 
-AstNode* ast_make_literal_f64(void* alloc, double val, int line, int col) {
+AstNode* ast_make_literal_f64(void* alloc, double val, SourceLoc loc) {
     NEW(alloc, AST_LITERAL_EXPR);
     n->as.literal.lit_type = TYPE_F64; n->as.literal.f64_val = val;
     n->type.kind = TYPE_F64;
     return n;
 }
 
-AstNode* ast_make_literal_bool(void* alloc, bool val, int line, int col) {
+AstNode* ast_make_literal_bool(void* alloc, bool val, SourceLoc loc) {
     NEW(alloc, AST_LITERAL_EXPR);
     n->as.literal.lit_type = TYPE_BOOL; n->as.literal.bool_val = val;
     n->type.kind = TYPE_BOOL;
     return n;
 }
 
-AstNode* ast_make_literal_str(void* alloc, const char* val, int line, int col) {
+AstNode* ast_make_literal_str(void* alloc, const char* val, SourceLoc loc) {
     NEW(alloc, AST_LITERAL_EXPR);
     n->as.literal.lit_type = TYPE_STR; n->as.literal.str_val = val;
     n->type.kind = TYPE_STR;
     return n;
 }
 
-AstNode* ast_make_ident(void* alloc, const char* name, int line, int col) {
+AstNode* ast_make_ident(void* alloc, const char* name, SourceLoc loc) {
     NEW(alloc, AST_IDENT_EXPR);
     n->as.ident.name = name;
     return n;
@@ -137,7 +138,7 @@ AstNode* ast_make_ident(void* alloc, const char* name, int line, int col) {
 // === 结构体相关工厂函数 ===
 
 AstNode* ast_make_struct_decl(void* alloc, const char* name, AstNode** fields,
-                               size_t count, int line, int col) {
+                               size_t count, SourceLoc loc) {
     NEW(alloc, AST_STRUCT_DECL);
     n->as.struct_decl.name = name;
     n->as.struct_decl.fields = fields;
@@ -147,7 +148,7 @@ AstNode* ast_make_struct_decl(void* alloc, const char* name, AstNode** fields,
 
 AstNode* ast_make_struct_init(void* alloc, const char* type_name,
                                const char** fnames, AstNode** fvals,
-                               size_t count, int line, int col) {
+                               size_t count, SourceLoc loc) {
     NEW(alloc, AST_STRUCT_INIT);
     n->as.struct_init.type_name = type_name;
     n->as.struct_init.field_names = fnames;
@@ -157,7 +158,7 @@ AstNode* ast_make_struct_init(void* alloc, const char* type_name,
 }
 
 AstNode* ast_make_field_access(void* alloc, AstNode* object, const char* field,
-                                int line, int col) {
+                                SourceLoc loc) {
     NEW(alloc, AST_FIELD_ACCESS);
     n->as.field_access.object = object;
     n->as.field_access.field = field;

src/ast/ast.h

@@ -42,8 +42,7 @@ typedef struct {
 struct AstNode {
     AstKind   kind;
     TypeInfo  type;         // 语义分析后填充，默认为 TYPE_UNKNOWN
-    int       line;         // 源文件行号
+    SourceLoc loc;          // 源码位置
-    int       col;          // 源文件列号
 
     // 节点特有数据（按 kind 解释）
     union {
@@ -52,7 +51,8 @@ struct AstNode {
                  struct AstNode** structs;   size_t struct_count; } program;
         // AST_FUNCTION
         struct { const char* name; struct AstNode** params; size_t param_count;
-                 TypeKind return_type; struct AstNode* body; } function;
+                 TypeKind return_type; const char* return_struct_type_name;
+                 struct AstNode* body; } function;
         // AST_PARAMETER (也用作结构体字段: name + type)
         struct { const char* name; TypeKind type; const char* struct_type_name; } parameter;
         // AST_BLOCK
@@ -92,28 +92,28 @@ struct AstNode {
 
 // 创建节点的辅助函数（内存来自 arena，通过 void* 传递避免循环依赖）
 AstNode* ast_make_program(void* alloc, AstNode** fns, size_t fn_count,
-                          AstNode** structs, size_t struct_count, int line, int col);
+                          AstNode** structs, size_t struct_count, SourceLoc loc);
 AstNode* ast_make_function(void* alloc, const char* name, AstNode** params, size_t pcount,
-                           TypeKind ret, AstNode* body, int line, int col);
+                           TypeKind ret, const char* ret_struct_name, AstNode* body, SourceLoc loc);
-AstNode* ast_make_parameter(void* alloc, const char* name, TypeKind type, const char* struct_type_name, int line, int col);
+AstNode* ast_make_parameter(void* alloc, const char* name, TypeKind type, const char* struct_type_name, SourceLoc loc);
-AstNode* ast_make_block(void* alloc, AstNode** stmts, size_t count, int line, int col);
+AstNode* ast_make_block(void* alloc, AstNode** stmts, size_t count, SourceLoc loc);
 AstNode* ast_make_let(void* alloc, const char* name, TypeKind annot_type, bool has_type_annot,
-                      bool is_mut, AstNode* init, const char* struct_type_name, int line, int col);
+                      bool is_mut, AstNode* init, const char* struct_type_name, SourceLoc loc);
-AstNode* ast_make_assign(void* alloc, const char* name, AstNode* value, int line, int col);
+AstNode* ast_make_assign(void* alloc, const char* name, AstNode* value, SourceLoc loc);
-AstNode* ast_make_if(void* alloc, AstNode* cond, AstNode* then_b, AstNode* else_b, int line, int col);
+AstNode* ast_make_if(void* alloc, AstNode* cond, AstNode* then_b, AstNode* else_b, SourceLoc loc);
-AstNode* ast_make_while(void* alloc, AstNode* cond, AstNode* body, int line, int col);
+AstNode* ast_make_while(void* alloc, AstNode* cond, AstNode* body, SourceLoc loc);
-AstNode* ast_make_return(void* alloc, AstNode* expr, int line, int col);
+AstNode* ast_make_return(void* alloc, AstNode* expr, SourceLoc loc);
-AstNode* ast_make_expr_stmt(void* alloc, AstNode* expr, int line, int col);
+AstNode* ast_make_expr_stmt(void* alloc, AstNode* expr, SourceLoc loc);
-AstNode* ast_make_binary(void* alloc, BinaryOp op, AstNode* left, AstNode* right, int line, int col);
+AstNode* ast_make_binary(void* alloc, BinaryOp op, AstNode* left, AstNode* right, SourceLoc loc);
-AstNode* ast_make_unary(void* alloc, BinaryOp op, AstNode* operand, int line, int col);
+AstNode* ast_make_unary(void* alloc, BinaryOp op, AstNode* operand, SourceLoc loc);
-AstNode* ast_make_call(void* alloc, const char* name, AstNode** args, size_t count, int line, int col);
+AstNode* ast_make_call(void* alloc, const char* name, AstNode** args, size_t count, SourceLoc loc);
-AstNode* ast_make_literal_i64(void* alloc, int64_t val, int line, int col);
+AstNode* ast_make_literal_i64(void* alloc, int64_t val, SourceLoc loc);
-AstNode* ast_make_literal_f64(void* alloc, double val, int line, int col);
+AstNode* ast_make_literal_f64(void* alloc, double val, SourceLoc loc);
-AstNode* ast_make_literal_bool(void* alloc, bool val, int line, int col);
+AstNode* ast_make_literal_bool(void* alloc, bool val, SourceLoc loc);
-AstNode* ast_make_literal_str(void* alloc, const char* val, int line, int col);
+AstNode* ast_make_literal_str(void* alloc, const char* val, SourceLoc loc);
-AstNode* ast_make_ident(void* alloc, const char* name, int line, int col);
+AstNode* ast_make_ident(void* alloc, const char* name, SourceLoc loc);
-AstNode* ast_make_struct_decl(void* alloc, const char* name, AstNode** fields, size_t count, int line, int col);
+AstNode* ast_make_struct_decl(void* alloc, const char* name, AstNode** fields, size_t count, SourceLoc loc);
-AstNode* ast_make_struct_init(void* alloc, const char* type_name, const char** fnames, AstNode** fvals, size_t count, int line, int col);
+AstNode* ast_make_struct_init(void* alloc, const char* type_name, const char** fnames, AstNode** fvals, size_t count, SourceLoc loc);
-AstNode* ast_make_field_access(void* alloc, AstNode* object, const char* field, int line, int col);
+AstNode* ast_make_field_access(void* alloc, AstNode* object, const char* field, SourceLoc loc);
 
 #endif

src/codegen/codegen.c

@@ -608,10 +608,23 @@ LLVMModuleRef codegen_module(AstNode* ast, Arena* codegen_arena,
         AstNode* fn = ast->as.program.functions[i];
         LLVMTypeRef* ptypes = arena_alloc(ctx.arena,
             fn->as.function.param_count * sizeof(LLVMTypeRef));
-        for (size_t j = 0; j < fn->as.function.param_count; j++)
+        for (size_t j = 0; j < fn->as.function.param_count; j++) {
-            ptypes[j] = to_llvm_type(&ctx, fn->as.function.params[j]->as.parameter.type);
+            AstNode* param = fn->as.function.params[j];
-        LLVMTypeRef fty = LLVMFunctionType(
+            if (param->as.parameter.type == TYPE_STRUCT &&
-            to_llvm_type(&ctx, fn->as.function.return_type),
+                param->as.parameter.struct_type_name) {
+                ptypes[j] = find_struct_type(&ctx, param->as.parameter.struct_type_name);
+            } else {
+                ptypes[j] = to_llvm_type(&ctx, param->as.parameter.type);
+            }
+        }
+        LLVMTypeRef ret_ty;
+        if (fn->as.function.return_type == TYPE_STRUCT &&
+            fn->as.function.return_struct_type_name) {
+            ret_ty = find_struct_type(&ctx, fn->as.function.return_struct_type_name);
+        } else {
+            ret_ty = to_llvm_type(&ctx, fn->as.function.return_type);
+        }
+        LLVMTypeRef fty = LLVMFunctionType(ret_ty,
             ptypes, (unsigned)fn->as.function.param_count, false);
         LLVMValueRef lfn = LLVMAddFunction(ctx.module, fn->as.function.name, fty);
         add_fn(&ctx, fn->as.function.name, lfn);
@@ -630,11 +643,18 @@ LLVMModuleRef codegen_module(AstNode* ast, Arena* codegen_arena,
         // 将参数注册为变量
         for (size_t j = 0; j < fn->as.function.param_count; j++) {
             LLVMValueRef param = LLVMGetParam(lfn, (unsigned)j);
+            AstNode* pnode = fn->as.function.params[j];
+            LLVMTypeRef param_ty;
+            if (pnode->as.parameter.type == TYPE_STRUCT &&
+                pnode->as.parameter.struct_type_name) {
+                param_ty = find_struct_type(&ctx, pnode->as.parameter.struct_type_name);
+            } else {
+                param_ty = to_llvm_type(&ctx, pnode->as.parameter.type);
+            }
             LLVMValueRef alloca = LLVMBuildAlloca(ctx.builder,
-                to_llvm_type(&ctx, fn->as.function.params[j]->as.parameter.type),
+                param_ty, pnode->as.parameter.name);
-                fn->as.function.params[j]->as.parameter.name);
             LLVMBuildStore(ctx.builder, param, alloca);
-            add_var(&ctx, fn->as.function.params[j]->as.parameter.name, alloca);
+            add_var(&ctx, pnode->as.parameter.name, alloca);
         }
 
         codegen_stmt(&ctx, fn->as.function.body);
@@ -645,6 +665,12 @@ LLVMModuleRef codegen_module(AstNode* ast, Arena* codegen_arena,
             cleanup_emit(&ctx, 0);
             if (fn->as.function.return_type == TYPE_VOID)
                 LLVMBuildRetVoid(ctx.builder);
+            else if (fn->as.function.return_type == TYPE_STRUCT &&
+                     fn->as.function.return_struct_type_name) {
+                LLVMTypeRef st_ty = find_struct_type(&ctx, fn->as.function.return_struct_type_name);
+                LLVMBuildRet(ctx.builder, st_ty ? LLVMConstNull(st_ty) :
+                    LLVMConstInt(to_llvm_type(&ctx, TYPE_I64), 0, false));
+            }
             else
                 LLVMBuildRet(ctx.builder,
                     (fn->as.function.return_type == TYPE_F64

src/lexer/token.h

@@ -41,6 +41,11 @@ struct Token {
 const char* tok_name(TokenKind kind);
 bool        tok_is_type(TokenKind kind);
 
+// 从 Token 创建 SourceLoc
+static inline SourceLoc tok_loc(const Token* tok) {
+    return (SourceLoc){ .line = tok->line, .col = tok->col };
+}
+
 // 从 Token 提取值
 int64_t  tok_int_value(const Token* tok);
 double   tok_float_value(const Token* tok);

src/parser/parser.c

@@ -78,7 +78,7 @@ static AstNode* parse_unary(Parser* p, ErrorInfo* error) {
     AstNode* operand = parse_expr_prec(p, PREC_UNARY, error);
     if (!operand) return NULL;
     BinaryOp uop = (op->kind == TOK_MINUS) ? OP_NEG : OP_NOT;
-    return ast_make_unary(p->arena, uop, operand, op->line, op->col);
+    return ast_make_unary(p->arena, uop, operand, tok_loc(op));
 }
 
 static AstNode* parse_group(Parser* p, ErrorInfo* error) {
@@ -92,15 +92,15 @@ static AstNode* parse_group(Parser* p, ErrorInfo* error) {
 static AstNode* parse_literal(Parser* p) {
     const Token* t = advance(p);
     switch (t->kind) {
-        case TOK_INT_LIT:   return ast_make_literal_i64(p->arena, tok_int_value(t), t->line, t->col);
+        case TOK_INT_LIT:   return ast_make_literal_i64(p->arena, tok_int_value(t), tok_loc(t));
-        case TOK_FLOAT_LIT: return ast_make_literal_f64(p->arena, tok_float_value(t), t->line, t->col);
+        case TOK_FLOAT_LIT: return ast_make_literal_f64(p->arena, tok_float_value(t), tok_loc(t));
-        case TOK_TRUE:      return ast_make_literal_bool(p->arena, true, t->line, t->col);
+        case TOK_TRUE:      return ast_make_literal_bool(p->arena, true, tok_loc(t));
-        case TOK_FALSE:     return ast_make_literal_bool(p->arena, false, t->line, t->col);
+        case TOK_FALSE:     return ast_make_literal_bool(p->arena, false, tok_loc(t));
         case TOK_STR_LIT: {
             char* str = arena_alloc_impl(p->arena, t->length + 1);
             memcpy(str, t->start, t->length);
             str[t->length] = '\0';
-            return ast_make_literal_str(p->arena, str, t->line, t->col);
+            return ast_make_literal_str(p->arena, str, tok_loc(t));
         }
         default: return NULL;
     }
@@ -137,7 +137,7 @@ static AstNode* parse_struct_init(Parser* p, const Token* name, ErrorInfo* error
 
     return ast_make_struct_init(p->arena,
         arena_strdup_impl(p->arena, name->start, name->length),
-        n_arr, v_arr, fcount, name->line, name->col);
+        n_arr, v_arr, fcount, tok_loc(name));
 }
 
 // === 标识符 / 函数调用 / 结构体初始化 ===
@@ -175,11 +175,11 @@ static AstNode* parse_ident_or_call(Parser* p, ErrorInfo* error) {
         AstNode** arg_arr = arena_alloc_impl(p->arena, arg_count * sizeof(AstNode*));
         memcpy(arg_arr, args, arg_count * sizeof(AstNode*));
         return ast_make_call(p->arena, arena_strdup_impl(p->arena, name->start, name->length),
-                            arg_arr, arg_count, name->line, name->col);
+                            arg_arr, arg_count, tok_loc(name));
     }
     return ast_make_ident(p->arena,
         arena_strdup_impl(p->arena, name->start, name->length),
-        name->line, name->col);
+        tok_loc(name));
 }
 
 // === Pratt 主循环 ===
@@ -216,7 +216,7 @@ static AstNode* parse_expr_prec(Parser* p, Precedence min_prec, ErrorInfo* error
             if (!field) return NULL;
             left = ast_make_field_access(p->arena, left,
                 arena_strdup_impl(p->arena, field->start, field->length),
-                field->line, field->col);
+                tok_loc(field));
             continue;
         }
 
@@ -227,7 +227,7 @@ static AstNode* parse_expr_prec(Parser* p, Precedence min_prec, ErrorInfo* error
         const Token* op = advance(p);
         AstNode* right = parse_expr_prec(p, prec, error);
         if (!right) return NULL;
-        left = ast_make_binary(p->arena, tok_to_binop(kind), left, right, op->line, op->col);
+        left = ast_make_binary(p->arena, tok_to_binop(kind), left, right, tok_loc(op));
     }
 
     return left;
@@ -271,7 +271,7 @@ static AstNode* parse_struct_decl(Parser* p, ErrorInfo* error) {
         }
         fields[fcount++] = ast_make_parameter(p->arena,
             arena_strdup_impl(p->arena, fname->start, fname->length),
-            field_kind, field_struct_name, fname->line, fname->col);
+            field_kind, field_struct_name, tok_loc(fname));
         if (peek(p)->kind == TOK_COMMA) advance(p);
         else break;
     }
@@ -281,7 +281,7 @@ static AstNode* parse_struct_decl(Parser* p, ErrorInfo* error) {
     memcpy(farr, fields, fcount * sizeof(AstNode*));
     return ast_make_struct_decl(p->arena,
         arena_strdup_impl(p->arena, name->start, name->length),
-        farr, fcount, s_tok->line, s_tok->col);
+        farr, fcount, tok_loc(s_tok));
 }
 
 // === 语句解析 ===
@@ -305,7 +305,7 @@ static AstNode* parse_block(Parser* p, ErrorInfo* error) {
     AstNode** arr = arena_alloc_impl(p->arena, count * sizeof(AstNode*));
     memcpy(arr, stmts, count * sizeof(AstNode*));
     parse_depth--;
-    return ast_make_block(p->arena, arr, count, open->line, open->col);
+    return ast_make_block(p->arena, arr, count, tok_loc(open));
 }
 
 static AstNode* parse_statement(Parser* p, ErrorInfo* error) {
@@ -342,7 +342,7 @@ static AstNode* parse_statement(Parser* p, ErrorInfo* error) {
         if (!expect(p, TOK_SEMICOLON, error, "缺少 ';'")) return NULL;
         return ast_make_let(p->arena,
             arena_strdup_impl(p->arena, name->start, name->length),
-            annot_type, has_type_annot, is_mut, init, struct_type_name, t->line, t->col);
+            annot_type, has_type_annot, is_mut, init, struct_type_name, tok_loc(t));
     }
 
     if (t->kind == TOK_IF) {
@@ -360,7 +360,7 @@ static AstNode* parse_statement(Parser* p, ErrorInfo* error) {
             }
             if (!else_block) return NULL;
         }
-        return ast_make_if(p->arena, cond, then_block, else_block, t->line, t->col);
+        return ast_make_if(p->arena, cond, then_block, else_block, tok_loc(t));
     }
 
     if (t->kind == TOK_WHILE) {
@@ -369,7 +369,7 @@ static AstNode* parse_statement(Parser* p, ErrorInfo* error) {
         if (!cond) return NULL;
         AstNode* body = parse_block(p, error);
         if (!body) return NULL;
-        return ast_make_while(p->arena, cond, body, t->line, t->col);
+        return ast_make_while(p->arena, cond, body, tok_loc(t));
     }
 
     if (t->kind == TOK_FOR) {
@@ -403,20 +403,20 @@ static AstNode* parse_statement(Parser* p, ErrorInfo* error) {
         const char* vname = arena_strdup_impl(p->arena, var_name->start, var_name->length);
 
         // 构建: let mut i = start;
-        AstNode* let_stmt = ast_make_let(p->arena, vname, TYPE_UNKNOWN, false, true, start_expr, NULL, var_name->line, var_name->col);
+        AstNode* let_stmt = ast_make_let(p->arena, vname, TYPE_UNKNOWN, false, true, start_expr, NULL, tok_loc(var_name));
 
         // 构建: i < end  (while 条件)
         AstNode* cond = ast_make_binary(p->arena, OP_LT,
-            ast_make_ident(p->arena, vname, var_name->line, var_name->col),
+            ast_make_ident(p->arena, vname, tok_loc(var_name)),
-            end_expr, var_name->line, var_name->col);
+            end_expr, tok_loc(var_name));
 
         // 构建: i = i + 1  (循环增量)
         AstNode* incr = ast_make_assign(p->arena, vname,
             ast_make_binary(p->arena, OP_ADD,
-                ast_make_ident(p->arena, vname, var_name->line, var_name->col),
+                ast_make_ident(p->arena, vname, tok_loc(var_name)),
-                ast_make_literal_i64(p->arena, 1, var_name->line, var_name->col),
+                ast_make_literal_i64(p->arena, 1, tok_loc(var_name)),
-                var_name->line, var_name->col),
+                tok_loc(var_name)),
-            var_name->line, var_name->col);
+            tok_loc(var_name));
 
         // 将增量追加到循环体末尾
         AstNode** new_stmts = arena_alloc_impl(p->arena,
@@ -424,27 +424,27 @@ static AstNode* parse_statement(Parser* p, ErrorInfo* error) {
         memcpy(new_stmts, body->as.block.stmts, body->as.block.stmt_count * sizeof(AstNode*));
         new_stmts[body->as.block.stmt_count] = incr;
         AstNode* new_body = ast_make_block(p->arena, new_stmts,
-            body->as.block.stmt_count + 1, body->line, body->col);
+            body->as.block.stmt_count + 1, body->loc);
 
         // 构建: while i < end { ... body ... ; i = i + 1; }
-        AstNode* while_loop = ast_make_while(p->arena, cond, new_body, t->line, t->col);
+        AstNode* while_loop = ast_make_while(p->arena, cond, new_body, tok_loc(t));
 
         // 包装: { let mut i = start; while i < end { ... } }
         AstNode* stmts_arr[2] = { let_stmt, while_loop };
         AstNode** stmts = arena_alloc_impl(p->arena, 2 * sizeof(AstNode*));
         memcpy(stmts, stmts_arr, 2 * sizeof(AstNode*));
-        return ast_make_block(p->arena, stmts, 2, t->line, t->col);
+        return ast_make_block(p->arena, stmts, 2, tok_loc(t));
     }
 
     if (t->kind == TOK_RETURN) {
         advance(p);
         if (match(p, TOK_SEMICOLON)) {
-            return ast_make_return(p->arena, NULL, t->line, t->col);
+            return ast_make_return(p->arena, NULL, tok_loc(t));
         }
         AstNode* expr = parse_expr(p, error);
         if (!expr) return NULL;
         if (!expect(p, TOK_SEMICOLON, error, "缺少 ';'")) return NULL;
-        return ast_make_return(p->arena, expr, t->line, t->col);
+        return ast_make_return(p->arena, expr, tok_loc(t));
     }
 
     // 赋值语句: ident = expr ;
@@ -456,7 +456,7 @@ static AstNode* parse_statement(Parser* p, ErrorInfo* error) {
         if (!expect(p, TOK_SEMICOLON, error, "缺少 ';'")) return NULL;
         return ast_make_assign(p->arena,
             arena_strdup_impl(p->arena, name->start, name->length),
-            value, name->line, name->col);
+            value, tok_loc(name));
     }
 
     // 复合赋值: ident += expr  →  ident = ident + expr
@@ -481,12 +481,12 @@ static AstNode* parse_statement(Parser* p, ErrorInfo* error) {
 
             AstNode* lhs_ident = ast_make_ident(p->arena,
                 arena_strdup_impl(p->arena, name->start, name->length),
-                name->line, name->col);
+                tok_loc(name));
             AstNode* bin_expr = ast_make_binary(p->arena, binop, lhs_ident, rhs,
-                name->line, name->col);
+                tok_loc(name));
             return ast_make_assign(p->arena,
                 arena_strdup_impl(p->arena, name->start, name->length),
-                bin_expr, name->line, name->col);
+                bin_expr, tok_loc(name));
         }
     }
 
@@ -494,7 +494,7 @@ static AstNode* parse_statement(Parser* p, ErrorInfo* error) {
     AstNode* expr = parse_expr(p, error);
     if (!expr) return NULL;
     if (!expect(p, TOK_SEMICOLON, error, "缺少 ';'")) return NULL;
-    return ast_make_expr_stmt(p->arena, expr, t->line, t->col);
+    return ast_make_expr_stmt(p->arena, expr, tok_loc(t));
 }
 
 // === 函数解析 ===
@@ -512,13 +512,20 @@ static AstNode* parse_function(Parser* p, ErrorInfo* error) {
         if (!pname) return NULL;
         if (!expect(p, TOK_COLON, error, "缺少 ':'")) return NULL;
         const Token* ptype = advance(p);
-        if (!tok_is_type(ptype->kind)) {
+        TypeKind param_kind;
+        const char* param_struct_name = NULL;
+        if (tok_is_type(ptype->kind)) {
+            param_kind = token_to_type(ptype->kind);
+        } else if (ptype->kind == TOK_IDENT) {
+            param_kind = TYPE_STRUCT;
+            param_struct_name = arena_strdup_impl(p->arena, ptype->start, ptype->length);
+        } else {
             error->message = "无效的参数类型"; error->filename = p->filename;
             error->line = ptype->line; error->col = ptype->col; return NULL;
         }
         params[pcount++] = ast_make_parameter(p->arena,
             arena_strdup_impl(p->arena, pname->start, pname->length),
-            token_to_type(ptype->kind), NULL, pname->line, pname->col);
+            param_kind, param_struct_name, tok_loc(pname));
         if (match(p, TOK_COMMA)) continue;
         else break;
     }
@@ -526,13 +533,18 @@ static AstNode* parse_function(Parser* p, ErrorInfo* error) {
 
     // 返回类型
     TypeKind ret = TYPE_VOID;
+    const char* ret_struct_name = NULL;
     if (match(p, TOK_ARROW)) {
         const Token* rt = advance(p);
-        if (!tok_is_type(rt->kind)) {
+        if (tok_is_type(rt->kind)) {
+            ret = token_to_type(rt->kind);
+        } else if (rt->kind == TOK_IDENT) {
+            ret = TYPE_STRUCT;
+            ret_struct_name = arena_strdup_impl(p->arena, rt->start, rt->length);
+        } else {
             error->message = "无效的返回类型"; error->filename = p->filename;
             error->line = rt->line; error->col = rt->col; return NULL;
         }
-        ret = token_to_type(rt->kind);
     }
 
     AstNode* body = parse_block(p, error);
@@ -542,7 +554,7 @@ static AstNode* parse_function(Parser* p, ErrorInfo* error) {
     memcpy(parr, params, pcount * sizeof(AstNode*));
     return ast_make_function(p->arena,
         arena_strdup_impl(p->arena, name->start, name->length),
-        parr, pcount, ret, body, fn_tok->line, fn_tok->col);
+        parr, pcount, ret, ret_struct_name, body, tok_loc(fn_tok));
 }
 
 // === 程序入口 ===
@@ -572,5 +584,5 @@ AstNode* parse(Arena* a, const Token* tokens, size_t count,
     memcpy(fn_arr, functions, fn_count * sizeof(AstNode*));
     AstNode** st_arr = arena_alloc_impl(a, struct_count * sizeof(AstNode*));
     memcpy(st_arr, structs, struct_count * sizeof(AstNode*));
-    return ast_make_program(a, fn_arr, fn_count, st_arr, struct_count, 0, 0);
+    return ast_make_program(a, fn_arr, fn_count, st_arr, struct_count, loc_at(0, 0));
 }

src/sema/sema.c

@@ -3,6 +3,7 @@
 
 // === 类型关系 ===
 static TypeKind current_return_type = TYPE_VOID;
+static const char* current_return_struct_name = NULL;
 
 static TypeKind promote(TypeKind a, TypeKind b) {
     if (a == TYPE_F64 || b == TYPE_F64) return TYPE_F64;
@@ -26,11 +27,11 @@ static void analyze_expr(AstNode* node, Scope* scope, ErrorList* errors, Arena*
     case AST_IDENT_EXPR: {
         Symbol* sym = scope_lookup(scope, node->as.ident.name);
         if (!sym) {
-            error_add(errors, "<sema>", node->line, node->col,
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
                       "未定义的变量 '%s'", node->as.ident.name);
             node->type.kind = TYPE_ERROR;
         } else if (sym->kind == SYM_FUNCTION) {
-            error_add(errors, "<sema>", node->line, node->col,
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
                       "'%s' 是函数，不能作为表达式使用", node->as.ident.name);
             node->type.kind = TYPE_ERROR;
         } else {
@@ -47,7 +48,7 @@ static void analyze_expr(AstNode* node, Scope* scope, ErrorList* errors, Arena*
         TypeKind inner = node->as.unary.operand->type.kind;
         if (node->as.unary.op == OP_NEG) {
             if (!is_numeric(inner)) {
-                error_add(errors, "<sema>", node->line, node->col,
+                error_add(errors, "<sema>", node->loc.line, node->loc.col,
                           "一元 '-' 只能用于数值类型");
                 node->type.kind = TYPE_ERROR;
             } else {
@@ -55,7 +56,7 @@ static void analyze_expr(AstNode* node, Scope* scope, ErrorList* errors, Arena*
             }
         } else {  // OP_NOT
             if (inner != TYPE_BOOL) {
-                error_add(errors, "<sema>", node->line, node->col,
+                error_add(errors, "<sema>", node->loc.line, node->loc.col,
                           "'!' 只能用于布尔类型，得到 '%s'", type_name(inner));
                 node->type.kind = TYPE_ERROR;
             } else {
@@ -77,7 +78,7 @@ static void analyze_expr(AstNode* node, Scope* scope, ErrorList* errors, Arena*
             if (l == TYPE_STR || r == TYPE_STR) {
                 // 字符串拼接：两边都必须是 str 类型
                 if (l != TYPE_STR || r != TYPE_STR) {
-                    error_add(errors, "<sema>", node->line, node->col,
+                    error_add(errors, "<sema>", node->loc.line, node->loc.col,
                               "字符串拼接需要两边都是 str 类型，得到 '%s' + '%s'",
                               type_name(l), type_name(r));
                     node->type.kind = TYPE_ERROR;
@@ -85,7 +86,7 @@ static void analyze_expr(AstNode* node, Scope* scope, ErrorList* errors, Arena*
                     node->type.kind = TYPE_STR;
                 }
             } else if (!is_numeric(l) || !is_numeric(r)) {
-                error_add(errors, "<sema>", node->line, node->col,
+                error_add(errors, "<sema>", node->loc.line, node->loc.col,
                           "算术运算需要数值类型");
                 node->type.kind = TYPE_ERROR;
             } else {
@@ -94,7 +95,7 @@ static void analyze_expr(AstNode* node, Scope* scope, ErrorList* errors, Arena*
             break;
         case OP_SUB: case OP_MUL: case OP_DIV: case OP_MOD:
             if (!is_numeric(l) || !is_numeric(r)) {
-                error_add(errors, "<sema>", node->line, node->col,
+                error_add(errors, "<sema>", node->loc.line, node->loc.col,
                           "算术运算需要数值类型");
                 node->type.kind = TYPE_ERROR;
             } else {
@@ -103,7 +104,7 @@ static void analyze_expr(AstNode* node, Scope* scope, ErrorList* errors, Arena*
             break;
         case OP_EQ: case OP_NE: case OP_LT: case OP_GT: case OP_LE: case OP_GE:
             if (!is_comparable(l, r)) {
-                error_add(errors, "<sema>", node->line, node->col,
+                error_add(errors, "<sema>", node->loc.line, node->loc.col,
                           "类型 '%s' 和 '%s' 无法比较", type_name(l), type_name(r));
                 node->type.kind = TYPE_ERROR;
             } else {
@@ -112,7 +113,7 @@ static void analyze_expr(AstNode* node, Scope* scope, ErrorList* errors, Arena*
             break;
         case OP_AND: case OP_OR:
             if (l != TYPE_BOOL || r != TYPE_BOOL) {
-                error_add(errors, "<sema>", node->line, node->col,
+                error_add(errors, "<sema>", node->loc.line, node->loc.col,
                           "逻辑运算需要布尔类型");
                 node->type.kind = TYPE_ERROR;
             } else {
@@ -127,7 +128,7 @@ static void analyze_expr(AstNode* node, Scope* scope, ErrorList* errors, Arena*
     case AST_CALL_EXPR: {
         Symbol* sym = scope_lookup(scope, node->as.call.name);
         if (!sym || sym->kind != SYM_FUNCTION) {
-            error_add(errors, "<sema>", node->line, node->col,
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
                       "未定义的函数 '%s'", node->as.call.name);
             node->type.kind = TYPE_ERROR;
             // 即使函数未定义，也要分析参数表达式（它们可能有更多错误）
@@ -137,7 +138,7 @@ static void analyze_expr(AstNode* node, Scope* scope, ErrorList* errors, Arena*
             break;
         }
         if (node->as.call.arg_count != sym->param_count) {
-            error_add(errors, "<sema>", node->line, node->col,
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
                       "函数 '%s' 需要 %zu 个参数，但提供了 %zu 个",
                       node->as.call.name, sym->param_count, node->as.call.arg_count);
             node->type.kind = TYPE_ERROR;
@@ -151,13 +152,30 @@ static void analyze_expr(AstNode* node, Scope* scope, ErrorList* errors, Arena*
             analyze_expr(node->as.call.args[i], scope, errors, a);
             TypeKind actual = node->as.call.args[i]->type.kind;
             TypeKind expected = sym->param_types[i];
-            if (actual != TYPE_ERROR && actual != expected) {
+            if (actual != TYPE_ERROR) {
-                error_add(errors, "<sema>", node->line, node->col,
+                if (expected == TYPE_STRUCT) {
-                          "参数 %zu 类型不匹配: 期望 '%s'，得到 '%s'",
+                    // 结构体参数：比较具体类型名
-                          i + 1, type_name(expected), type_name(actual));
+                    const char* actual_name = node->as.call.args[i]->type.struct_name;
+                    const char* expected_name = sym->param_struct_names ? sym->param_struct_names[i] : NULL;
+                    if (actual != TYPE_STRUCT || !actual_name || !expected_name ||
+                        strcmp(actual_name, expected_name) != 0) {
+                        error_add(errors, "<sema>", node->loc.line, node->loc.col,
+                                  "参数 %zu 类型不匹配: 期望 '%s'，得到 '%s'",
+                                  i + 1,
+                                  expected_name ? expected_name : "struct",
+                                  actual_name ? actual_name : type_name(actual));
+                    }
+                } else if (actual != expected) {
+                    error_add(errors, "<sema>", node->loc.line, node->loc.col,
+                              "参数 %zu 类型不匹配: 期望 '%s'，得到 '%s'",
+                              i + 1, type_name(expected), type_name(actual));
+                }
             }
         }
         node->type.kind = sym->return_type;
+        if (sym->return_type == TYPE_STRUCT && sym->return_struct_type_name) {
+            node->type.struct_name = sym->return_struct_type_name;
+        }
         break;
     }
 
@@ -169,7 +187,7 @@ static void analyze_expr(AstNode* node, Scope* scope, ErrorList* errors, Arena*
             break;
         }
         if (obj->type.kind != TYPE_STRUCT) {
-            error_add(errors, "<sema>", node->line, node->col,
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
                       "类型 '%s' 不是结构体，不能访问字段 '%s'",
                       type_name(obj->type.kind), node->as.field_access.field);
             node->type.kind = TYPE_ERROR;
@@ -178,21 +196,21 @@ static void analyze_expr(AstNode* node, Scope* scope, ErrorList* errors, Arena*
         // 查找结构体定义
         const char* struct_name = obj->type.struct_name;
         if (!struct_name) {
-            error_add(errors, "<sema>", node->line, node->col,
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
                       "无法确定结构体类型");
             node->type.kind = TYPE_ERROR;
             break;
         }
         Symbol* struct_sym = scope_lookup_struct(scope, struct_name);
         if (!struct_sym) {
-            error_add(errors, "<sema>", node->line, node->col,
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
                       "未定义的结构体 '%s'", struct_name);
             node->type.kind = TYPE_ERROR;
             break;
         }
         int fi = scope_struct_field_index(struct_sym, node->as.field_access.field);
         if (fi < 0) {
-            error_add(errors, "<sema>", node->line, node->col,
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
                       "结构体 '%s' 没有字段 '%s'", struct_name, node->as.field_access.field);
             node->type.kind = TYPE_ERROR;
             break;
@@ -211,13 +229,13 @@ static void analyze_expr(AstNode* node, Scope* scope, ErrorList* errors, Arena*
     case AST_STRUCT_INIT: {
         Symbol* struct_sym = scope_lookup_struct(scope, node->as.struct_init.type_name);
         if (!struct_sym) {
-            error_add(errors, "<sema>", node->line, node->col,
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
                       "未定义的结构体类型 '%s'", node->as.struct_init.type_name);
             node->type.kind = TYPE_ERROR;
             break;
         }
         if (node->as.struct_init.field_count != struct_sym->struct_field_count) {
-            error_add(errors, "<sema>", node->line, node->col,
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
                       "结构体 '%s' 有 %zu 个字段，但提供了 %zu 个",
                       node->as.struct_init.type_name,
                       struct_sym->struct_field_count,
@@ -233,7 +251,7 @@ static void analyze_expr(AstNode* node, Scope* scope, ErrorList* errors, Arena*
 
             int fi = scope_struct_field_index(struct_sym, fname);
             if (fi < 0) {
-                error_add(errors, "<sema>", node->line, node->col,
+                error_add(errors, "<sema>", node->loc.line, node->loc.col,
                           "结构体 '%s' 没有字段 '%s'",
                           node->as.struct_init.type_name, fname);
                 node->type.kind = TYPE_ERROR;
@@ -242,7 +260,7 @@ static void analyze_expr(AstNode* node, Scope* scope, ErrorList* errors, Arena*
             TypeKind expected = struct_sym->struct_field_types[fi];
             TypeKind actual = fval->type.kind;
             if (actual != TYPE_ERROR && actual != expected) {
-                error_add(errors, "<sema>", node->line, node->col,
+                error_add(errors, "<sema>", node->loc.line, node->loc.col,
                           "字段 '%s' 类型不匹配: 期望 '%s'，得到 '%s'",
                           fname, type_name(expected), type_name(actual));
             }
@@ -285,11 +303,15 @@ static void analyze_node(AstNode* node, Scope* scope, ErrorList* errors, Arena*
         for (size_t i = 0; i < node->as.program.fn_count; i++) {
             AstNode* fn = node->as.program.functions[i];
             TypeKind* pts = (TypeKind*)arena_alloc_impl(a, fn->as.function.param_count * sizeof(TypeKind));
+            const char** pstruct_names = (const char**)arena_alloc_impl(a, fn->as.function.param_count * sizeof(const char*));
             for (size_t j = 0; j < fn->as.function.param_count; j++) {
                 pts[j] = fn->as.function.params[j]->as.parameter.type;
+                pstruct_names[j] = fn->as.function.params[j]->as.parameter.struct_type_name;
             }
             scope_insert_function(scope, a, fn->as.function.name,
-                                  fn->as.function.return_type, pts,
+                                  fn->as.function.return_type,
+                                  fn->as.function.return_struct_type_name,
+                                  pts, pstruct_names,
                                   fn->as.function.param_count);
         }
         // 第三遍：分析每个函数体
@@ -303,12 +325,18 @@ static void analyze_node(AstNode* node, Scope* scope, ErrorList* errors, Arena*
         // 注册参数
         for (size_t i = 0; i < node->as.function.param_count; i++) {
             AstNode* p = node->as.function.params[i];
-            scope_insert(fn_scope, a, p->as.parameter.name, SYM_PARAMETER, p->as.parameter.type);
+            Symbol* sym = scope_insert(fn_scope, a, p->as.parameter.name, SYM_PARAMETER, p->as.parameter.type);
+            if (sym && p->as.parameter.type == TYPE_STRUCT && p->as.parameter.struct_type_name) {
+                sym->struct_type_name = p->as.parameter.struct_type_name;
+            }
         }
         TypeKind saved = current_return_type;
+        const char* saved_name = current_return_struct_name;
         current_return_type = node->as.function.return_type;
+        current_return_struct_name = node->as.function.return_struct_type_name;
         analyze_node(node->as.function.body, fn_scope, errors, a);
         current_return_type = saved;
+        current_return_struct_name = saved_name;
         break;
     }
 
@@ -330,7 +358,7 @@ static void analyze_node(AstNode* node, Scope* scope, ErrorList* errors, Arena*
                 // struct 类型标注
                 Symbol* st_sym = scope_lookup_struct(scope, annot_struct);
                 if (!st_sym) {
-                    error_add(errors, "<sema>", node->line, node->col,
+                    error_add(errors, "<sema>", node->loc.line, node->loc.col,
                               "未定义的结构体类型 '%s'", annot_struct);
                     break;
                 }
@@ -340,7 +368,7 @@ static void analyze_node(AstNode* node, Scope* scope, ErrorList* errors, Arena*
                 var_type = node->as.let_stmt.annot_type;
             }
             if (inferred != TYPE_ERROR && inferred != var_type) {
-                error_add(errors, "<sema>", node->line, node->col,
+                error_add(errors, "<sema>", node->loc.line, node->loc.col,
                           "变量 '%s' 类型标注为 '%s'，但初始化表达式类型为 '%s'",
                           node->as.let_stmt.name,
                           annot_struct ? annot_struct : type_name(var_type),
@@ -349,7 +377,7 @@ static void analyze_node(AstNode* node, Scope* scope, ErrorList* errors, Arena*
         } else {
             // 类型推断
             if (inferred == TYPE_ERROR || inferred == TYPE_VOID) {
-                error_add(errors, "<sema>", node->line, node->col,
+                error_add(errors, "<sema>", node->loc.line, node->loc.col,
                           "无法从表达式推断变量 '%s' 的类型", node->as.let_stmt.name);
                 break;
             }
@@ -363,7 +391,7 @@ static void analyze_node(AstNode* node, Scope* scope, ErrorList* errors, Arena*
         node->type.struct_name = var_struct_name;
         Symbol* sym = scope_insert(scope, a, node->as.let_stmt.name, SYM_VARIABLE, var_type);
         if (!sym) {
-            error_add(errors, "<sema>", node->line, node->col,
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
                       "变量 '%s' 重复定义", node->as.let_stmt.name);
         } else {
             sym->is_mut = node->as.let_stmt.is_mut;
@@ -378,19 +406,19 @@ static void analyze_node(AstNode* node, Scope* scope, ErrorList* errors, Arena*
     case AST_ASSIGN_STMT: {
         Symbol* sym = scope_lookup(scope, node->as.assign_stmt.name);
         if (!sym) {
-            error_add(errors, "<sema>", node->line, node->col,
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
                       "未定义的变量 '%s'", node->as.assign_stmt.name);
             node->type.kind = TYPE_ERROR;
             break;
         }
         if (sym->kind != SYM_VARIABLE) {
-            error_add(errors, "<sema>", node->line, node->col,
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
                       "'%s' 不是变量，不能赋值", node->as.assign_stmt.name);
             node->type.kind = TYPE_ERROR;
             break;
         }
         if (!sym->is_mut) {
-            error_add(errors, "<sema>", node->line, node->col,
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
                       "不能对不可变变量 '%s' 赋值（需用 let mut 声明）",
                       node->as.assign_stmt.name);
             node->type.kind = TYPE_ERROR;
@@ -399,7 +427,7 @@ static void analyze_node(AstNode* node, Scope* scope, ErrorList* errors, Arena*
         analyze_expr(node->as.assign_stmt.value, scope, errors, a);
         TypeKind value_ty = node->as.assign_stmt.value->type.kind;
         if (value_ty != TYPE_ERROR && value_ty != sym->type) {
-            error_add(errors, "<sema>", node->line, node->col,
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
                       "赋值类型不匹配: 变量 '%s' 类型为 '%s'，但表达式类型为 '%s'",
                       node->as.assign_stmt.name, type_name(sym->type), type_name(value_ty));
         }
@@ -411,7 +439,7 @@ static void analyze_node(AstNode* node, Scope* scope, ErrorList* errors, Arena*
         analyze_expr(node->as.if_stmt.cond, scope, errors, a);
         if (node->as.if_stmt.cond->type.kind != TYPE_BOOL &&
             node->as.if_stmt.cond->type.kind != TYPE_ERROR) {
-            error_add(errors, "<sema>", node->line, node->col, "if 条件必须是布尔类型");
+            error_add(errors, "<sema>", node->loc.line, node->loc.col, "if 条件必须是布尔类型");
         }
         analyze_node(node->as.if_stmt.then_block, scope, errors, a);
         if (node->as.if_stmt.else_block) {
@@ -423,7 +451,7 @@ static void analyze_node(AstNode* node, Scope* scope, ErrorList* errors, Arena*
         analyze_expr(node->as.while_stmt.cond, scope, errors, a);
         if (node->as.while_stmt.cond->type.kind != TYPE_BOOL &&
             node->as.while_stmt.cond->type.kind != TYPE_ERROR) {
-            error_add(errors, "<sema>", node->line, node->col, "while 条件必须是布尔类型");
+            error_add(errors, "<sema>", node->loc.line, node->loc.col, "while 条件必须是布尔类型");
         }
         analyze_node(node->as.while_stmt.body, scope, errors, a);
         break;
@@ -434,14 +462,28 @@ static void analyze_node(AstNode* node, Scope* scope, ErrorList* errors, Arena*
             node->type.kind = node->as.return_stmt.expr->type.kind;
             TypeKind actual = node->as.return_stmt.expr->type.kind;
             TypeKind expected = current_return_type;
-            if (actual != TYPE_ERROR && expected != TYPE_VOID && actual != expected) {
+            if (actual != TYPE_ERROR && expected != TYPE_VOID) {
-                error_add(errors, "<sema>", node->line, node->col,
+                if (expected == TYPE_STRUCT) {
-                          "返回类型不匹配: 期望 '%s'，得到 '%s'",
+                    // 结构体返回类型：比较具体类型名
-                          type_name(expected), type_name(actual));
+                    const char* actual_name = node->as.return_stmt.expr->type.struct_name;
+                    const char* expected_name = current_return_struct_name;
+                    if (actual != TYPE_STRUCT || !actual_name || !expected_name ||
+                        strcmp(actual_name, expected_name) != 0) {
+                        error_add(errors, "<sema>", node->loc.line, node->loc.col,
+                                  "返回类型不匹配: 期望 '%s'，得到 '%s'",
+                                  expected_name ? expected_name : "struct",
+                                  actual_name ? actual_name : type_name(actual));
+                    }
+                } else if (actual != expected) {
+                    error_add(errors, "<sema>", node->loc.line, node->loc.col,
+                              "返回类型不匹配: 期望 '%s'，得到 '%s'",
+                              type_name(expected), type_name(actual));
+                }
             }
         } else if (current_return_type != TYPE_VOID) {
-            error_add(errors, "<sema>", node->line, node->col,
+            error_add(errors, "<sema>", node->loc.line, node->loc.col,
-                      "函数应返回值类型 '%s'", type_name(current_return_type));
+                      "函数应返回值类型 '%s'",
+                      current_return_struct_name ? current_return_struct_name : type_name(current_return_type));
         }
         break;
 
@@ -460,13 +502,13 @@ void sema_analyze(AstNode* ast, ErrorList* errors, Arena* arena) {
 
     // 注册内置函数
     TypeKind params_i64[] = {TYPE_I64};
-    scope_insert_function(global_scope, arena, "print_i64", TYPE_VOID, params_i64, 1);
+    scope_insert_function(global_scope, arena, "print_i64", TYPE_VOID, NULL, params_i64, NULL, 1);
     TypeKind params_f64[] = {TYPE_F64};
-    scope_insert_function(global_scope, arena, "print_f64", TYPE_VOID, params_f64, 1);
+    scope_insert_function(global_scope, arena, "print_f64", TYPE_VOID, NULL, params_f64, NULL, 1);
     TypeKind params_bool[] = {TYPE_BOOL};
-    scope_insert_function(global_scope, arena, "print_bool", TYPE_VOID, params_bool, 1);
+    scope_insert_function(global_scope, arena, "print_bool", TYPE_VOID, NULL, params_bool, NULL, 1);
     TypeKind params_str[] = {TYPE_STR};
-    scope_insert_function(global_scope, arena, "print_str", TYPE_VOID, params_str, 1);
+    scope_insert_function(global_scope, arena, "print_str", TYPE_VOID, NULL, params_str, NULL, 1);
 
     analyze_node(ast, global_scope, errors, arena);
 }

src/sema/symbol.c

@@ -41,7 +41,8 @@ Symbol* scope_insert(Scope* scope, void* alloc, const char* name,
 }
 
 Symbol* scope_insert_function(Scope* scope, void* alloc, const char* name,
-                              TypeKind ret, TypeKind* pt, size_t pc) {
+                              TypeKind ret, const char* ret_struct_name,
+                              TypeKind* pt, const char** pstruct_names, size_t pc) {
     if (scope->head) {
         for (Symbol* sym = scope->head; sym; sym = sym->next) {
             if (strcmp(sym->name, name) == 0) return NULL;
@@ -50,7 +51,11 @@ Symbol* scope_insert_function(Scope* scope, void* alloc, const char* name,
     Symbol* sym = (Symbol*)arena_alloc_impl(alloc, sizeof(Symbol));
     if (!sym) return NULL;
     sym->name = name; sym->kind = SYM_FUNCTION; sym->type = TYPE_VOID;
-    sym->return_type = ret; sym->param_types = pt; sym->param_count = pc;
+    sym->return_type = ret;
+    sym->return_struct_type_name = ret_struct_name;
+    sym->param_types = pt;
+    sym->param_struct_names = pstruct_names;
+    sym->param_count = pc;
     sym->struct_field_names = NULL;
     sym->struct_field_types = NULL;
     sym->struct_field_count = 0;

src/sema/symbol.h

@@ -13,7 +13,9 @@ typedef struct Symbol {
     bool        is_mut;        // 变量是否可变（可被赋值）
     // 函数特有
     TypeKind    return_type;
+    const char* return_struct_type_name;  // 返回类型为 struct 时的类型名
     TypeKind*   param_types;
+    const char** param_struct_names;      // 参数为 struct 时的类型名
     size_t       param_count;
     // 结构体特有（SYM_STRUCT）
     const char** struct_field_names;
@@ -43,7 +45,8 @@ Symbol* scope_insert(Scope* scope, void* alloc, const char* name,
 
 // 插入函数符号
 Symbol* scope_insert_function(Scope* scope, void* alloc, const char* name,
-                              TypeKind ret, TypeKind* pt, size_t pc);
+                              TypeKind ret, const char* ret_struct_name,
+                              TypeKind* pt, const char** pstruct_names, size_t pc);
 
 // 插入结构体符号
 Symbol* scope_insert_struct(Scope* scope, void* alloc, const char* name,

test/programs/14_struct_fn.l

@@ -0,0 +1,19 @@
+struct Point {
+    x: i64,
+    y: i64,
+}
+
+fn make_point(x: i64, y: i64) -> Point {
+    return Point { x: x, y: y };
+}
+
+fn print_point(p: Point) -> void {
+    print_i64(p.x);
+    print_i64(p.y);
+}
+
+fn main() -> i64 {
+    let p: Point = make_point(3, 4);
+    print_point(p);
+    return 0;
+}

test/test_codegen.c

@@ -8,12 +8,12 @@ void test_codegen_simple_function() {
     Arena a = arena_create(1);
 
     // 构造 AST: fn main() -> i64 { return 42; }
-    AstNode* ret = ast_make_return(&a, ast_make_literal_i64(&a, 42, 1, 1), 1, 1);
+    AstNode* ret = ast_make_return(&a, ast_make_literal_i64(&a, 42, loc_at(1, 1)), loc_at(1, 1));
     AstNode* stmts[] = { ret };
-    AstNode* body = ast_make_block(&a, stmts, 1, 1, 1);
+    AstNode* body = ast_make_block(&a, stmts, 1, loc_at(1, 1));
-    AstNode* fn = ast_make_function(&a, "main", NULL, 0, TYPE_I64, body, 1, 1);
+    AstNode* fn = ast_make_function(&a, "main", NULL, 0, TYPE_I64, NULL, body, loc_at(1, 1));
     AstNode* fns[] = { fn };
-    AstNode* prog = ast_make_program(&a, fns, 1, NULL, 0, 1, 1);
+    AstNode* prog = ast_make_program(&a, fns, 1, NULL, 0, loc_at(1, 1));
 
     const char* err = NULL;
     LLVMContextRef ctx = NULL;
@@ -35,19 +35,19 @@ void test_codegen_if_else() {
     Arena a = arena_create(1);
 
     // fn main() -> i64 { if true { return 1; } else { return 0; } }
-    AstNode* then_ret = ast_make_return(&a, ast_make_literal_i64(&a, 1, 1, 1), 1, 1);
+    AstNode* then_ret = ast_make_return(&a, ast_make_literal_i64(&a, 1, loc_at(1, 1)), loc_at(1, 1));
     AstNode* then_stmts[] = { then_ret };
-    AstNode* then_block = ast_make_block(&a, then_stmts, 1, 1, 1);
+    AstNode* then_block = ast_make_block(&a, then_stmts, 1, loc_at(1, 1));
-    AstNode* else_ret = ast_make_return(&a, ast_make_literal_i64(&a, 0, 1, 1), 1, 1);
+    AstNode* else_ret = ast_make_return(&a, ast_make_literal_i64(&a, 0, loc_at(1, 1)), loc_at(1, 1));
     AstNode* else_stmts[] = { else_ret };
-    AstNode* else_block = ast_make_block(&a, else_stmts, 1, 1, 1);
+    AstNode* else_block = ast_make_block(&a, else_stmts, 1, loc_at(1, 1));
     AstNode* if_stmt = ast_make_if(&a,
-        ast_make_literal_bool(&a, true, 1, 1), then_block, else_block, 1, 1);
+        ast_make_literal_bool(&a, true, loc_at(1, 1)), then_block, else_block, loc_at(1, 1));
     AstNode* stmts[] = { if_stmt };
-    AstNode* body = ast_make_block(&a, stmts, 1, 1, 1);
+    AstNode* body = ast_make_block(&a, stmts, 1, loc_at(1, 1));
-    AstNode* fn = ast_make_function(&a, "main", NULL, 0, TYPE_I64, body, 1, 1);
+    AstNode* fn = ast_make_function(&a, "main", NULL, 0, TYPE_I64, NULL, body, loc_at(1, 1));
     AstNode* fns[] = { fn };
-    AstNode* prog = ast_make_program(&a, fns, 1, NULL, 0, 1, 1);
+    AstNode* prog = ast_make_program(&a, fns, 1, NULL, 0, loc_at(1, 1));
 
     const char* err = NULL;
     LLVMContextRef ctx2 = NULL;
@@ -68,17 +68,17 @@ void test_codegen_binary_ops() {
 
     // fn main() -> i64 { return 1 + 2 * 3; }
     AstNode* expr = ast_make_binary(&a, OP_ADD,
-        ast_make_literal_i64(&a, 1, 1, 1),
+        ast_make_literal_i64(&a, 1, loc_at(1, 1)),
         ast_make_binary(&a, OP_MUL,
-            ast_make_literal_i64(&a, 2, 1, 1),
+            ast_make_literal_i64(&a, 2, loc_at(1, 1)),
-            ast_make_literal_i64(&a, 3, 1, 1), 1, 1),
+            ast_make_literal_i64(&a, 3, loc_at(1, 1)), loc_at(1, 1)),
-        1, 1);
+        loc_at(1, 1));
-    AstNode* ret = ast_make_return(&a, expr, 1, 1);
+    AstNode* ret = ast_make_return(&a, expr, loc_at(1, 1));
     AstNode* stmts[] = { ret };
-    AstNode* body = ast_make_block(&a, stmts, 1, 1, 1);
+    AstNode* body = ast_make_block(&a, stmts, 1, loc_at(1, 1));
-    AstNode* fn = ast_make_function(&a, "main", NULL, 0, TYPE_I64, body, 1, 1);
+    AstNode* fn = ast_make_function(&a, "main", NULL, 0, TYPE_I64, NULL, body, loc_at(1, 1));
     AstNode* fns[] = { fn };
-    AstNode* prog = ast_make_program(&a, fns, 1, NULL, 0, 1, 1);
+    AstNode* prog = ast_make_program(&a, fns, 1, NULL, 0, loc_at(1, 1));
 
     const char* err = NULL;
     LLVMContextRef ctx3 = NULL;
@@ -98,17 +98,17 @@ void test_codegen_while_loop() {
     Arena a = arena_create(1);
     // fn main() -> i64 { while true { return 0; } return 1; }
     AstNode* while_body_stmts[] = {
-        ast_make_return(&a, ast_make_literal_i64(&a, 0, 1, 1), 1, 1)
+        ast_make_return(&a, ast_make_literal_i64(&a, 0, loc_at(1, 1)), loc_at(1, 1))
     };
-    AstNode* while_body = ast_make_block(&a, while_body_stmts, 1, 1, 1);
+    AstNode* while_body = ast_make_block(&a, while_body_stmts, 1, loc_at(1, 1));
     AstNode* while_stmt = ast_make_while(&a,
-        ast_make_literal_bool(&a, true, 1, 1), while_body, 1, 1);
+        ast_make_literal_bool(&a, true, loc_at(1, 1)), while_body, loc_at(1, 1));
-    AstNode* ret = ast_make_return(&a, ast_make_literal_i64(&a, 1, 1, 1), 1, 1);
+    AstNode* ret = ast_make_return(&a, ast_make_literal_i64(&a, 1, loc_at(1, 1)), loc_at(1, 1));
     AstNode* stmts[] = { while_stmt, ret };
-    AstNode* fn_body = ast_make_block(&a, stmts, 2, 1, 1);
+    AstNode* fn_body = ast_make_block(&a, stmts, 2, loc_at(1, 1));
-    AstNode* fn = ast_make_function(&a, "main", NULL, 0, TYPE_I64, fn_body, 1, 1);
+    AstNode* fn = ast_make_function(&a, "main", NULL, 0, TYPE_I64, NULL, fn_body, loc_at(1, 1));
     AstNode* fns[] = { fn };
-    AstNode* prog = ast_make_program(&a, fns, 1, NULL, 0, 1, 1);
+    AstNode* prog = ast_make_program(&a, fns, 1, NULL, 0, loc_at(1, 1));
 
     const char* err = NULL;
     LLVMContextRef ctx4 = NULL;
@@ -121,10 +121,125 @@ void test_codegen_while_loop() {
     arena_destroy(&a);
 }
 
+/* === struct IR 生成测试 === */
+
+void test_codegen_struct_decl() {
+    Arena a = arena_create(1);
+
+    /* 构造 AST: struct Point { x: i64, y: i64 } */
+    AstNode* fields[2];
+    fields[0] = ast_make_parameter(&a, "x", TYPE_I64, NULL, loc_at(1, 1));
+    fields[1] = ast_make_parameter(&a, "y", TYPE_I64, NULL, loc_at(1, 1));
+    AstNode* struct_decl = ast_make_struct_decl(&a, "Point", fields, 2, loc_at(1, 1));
+    AstNode* structs[] = { struct_decl };
+
+    /* 构造 fn main() -> i64 { let p = Point { x: 1, y: 2 }; return p.x; } */
+    const char* fnames[] = {"x", "y"};
+    AstNode* fvals[] = {
+        ast_make_literal_i64(&a, 1, loc_at(1, 1)),
+        ast_make_literal_i64(&a, 2, loc_at(1, 1))
+    };
+    AstNode* init = ast_make_struct_init(&a, "Point", fnames, fvals, 2, loc_at(1, 1));
+    /* 手动设置类型（绕过 sema，codegen 需要读取 type 字段） */
+    init->type.kind = TYPE_STRUCT;
+    init->type.struct_name = "Point";
+
+    AstNode* let_stmt = ast_make_let(&a, "p", TYPE_UNKNOWN, false, false,
+                                     init, NULL, loc_at(1, 1));
+
+    /* return p.x; */
+    AstNode* p_ident = ast_make_ident(&a, "p", loc_at(1, 1));
+    p_ident->type.kind = TYPE_STRUCT;
+    p_ident->type.struct_name = "Point";
+
+    AstNode* field_x = ast_make_field_access(&a, p_ident, "x", loc_at(1, 1));
+    field_x->as.field_access.field_index = 0;  /* x 是第 0 个字段 */
+    field_x->type.kind = TYPE_I64;
+
+    AstNode* ret = ast_make_return(&a, field_x, loc_at(1, 1));
+    AstNode* stmts[] = { let_stmt, ret };
+    AstNode* body = ast_make_block(&a, stmts, 2, loc_at(1, 1));
+    AstNode* fn = ast_make_function(&a, "main", NULL, 0, TYPE_I64, NULL, body, loc_at(1, 1));
+    AstNode* fns[] = { fn };
+
+    AstNode* prog = ast_make_program(&a, fns, 1, structs, 1, loc_at(1, 1));
+
+    const char* err = NULL;
+    LLVMContextRef ctx = NULL;
+    LLVMModuleRef mod = codegen_module(prog, &a, "test_struct_decl", &err, &ctx);
+    ASSERT(mod != NULL);
+    ASSERT(err == NULL);
+
+    char* verify_err = NULL;
+    int failed = LLVMVerifyModule(mod, LLVMReturnStatusAction, &verify_err);
+    ASSERT(!failed);
+
+    LLVMDisposeModule(mod);
+    LLVMContextDispose(ctx);
+    arena_destroy(&a);
+}
+
+void test_codegen_struct_field_access() {
+    Arena a = arena_create(1);
+
+    /* 构造 AST: struct Point { x: i64, y: i64 } */
+    AstNode* fields[2];
+    fields[0] = ast_make_parameter(&a, "x", TYPE_I64, NULL, loc_at(1, 1));
+    fields[1] = ast_make_parameter(&a, "y", TYPE_I64, NULL, loc_at(1, 1));
+    AstNode* struct_decl = ast_make_struct_decl(&a, "Point", fields, 2, loc_at(1, 1));
+    AstNode* structs[] = { struct_decl };
+
+    /* 构造 fn main() -> i64 { let p = Point { x: 5, y: 10 }; return p.y; } */
+    const char* fnames[] = {"x", "y"};
+    AstNode* fvals[] = {
+        ast_make_literal_i64(&a, 5, loc_at(1, 1)),
+        ast_make_literal_i64(&a, 10, loc_at(1, 1))
+    };
+    AstNode* init = ast_make_struct_init(&a, "Point", fnames, fvals, 2, loc_at(1, 1));
+    init->type.kind = TYPE_STRUCT;
+    init->type.struct_name = "Point";
+
+    AstNode* let_stmt = ast_make_let(&a, "p", TYPE_UNKNOWN, false, false,
+                                     init, NULL, loc_at(1, 1));
+
+    /* return p.y; */
+    AstNode* p_ident = ast_make_ident(&a, "p", loc_at(1, 1));
+    p_ident->type.kind = TYPE_STRUCT;
+    p_ident->type.struct_name = "Point";
+
+    AstNode* field_y = ast_make_field_access(&a, p_ident, "y", loc_at(1, 1));
+    field_y->as.field_access.field_index = 1;  /* y 是第 1 个字段 */
+    field_y->type.kind = TYPE_I64;
+
+    AstNode* ret = ast_make_return(&a, field_y, loc_at(1, 1));
+    AstNode* stmts[] = { let_stmt, ret };
+    AstNode* body = ast_make_block(&a, stmts, 2, loc_at(1, 1));
+    AstNode* fn = ast_make_function(&a, "main", NULL, 0, TYPE_I64, NULL, body, loc_at(1, 1));
+    AstNode* fns[] = { fn };
+
+    AstNode* prog = ast_make_program(&a, fns, 1, structs, 1, loc_at(1, 1));
+
+    const char* err = NULL;
+    LLVMContextRef ctx = NULL;
+    LLVMModuleRef mod = codegen_module(prog, &a, "test_struct_field", &err, &ctx);
+    ASSERT(mod != NULL);
+    ASSERT(err == NULL);
+
+    char* verify_err = NULL;
+    int failed = LLVMVerifyModule(mod, LLVMReturnStatusAction, &verify_err);
+    ASSERT(!failed);
+
+    LLVMDisposeModule(mod);
+    LLVMContextDispose(ctx);
+    arena_destroy(&a);
+}
+
 int main(void) {
     TEST_RUN(test_codegen_simple_function);
     TEST_RUN(test_codegen_if_else);
     TEST_RUN(test_codegen_binary_ops);
     TEST_RUN(test_codegen_while_loop);
+    TEST_RUN(test_codegen_struct_decl);
+    TEST_RUN(test_codegen_struct_field_access);
     return test_summary();
 }

test/test_sema.c

@@ -115,6 +115,76 @@ void test_str_concat_type_ok() {
     arena_destroy(&a);
 }
 
+/* === struct 类型检查测试 === */
+
+void test_struct_field_type_mismatch() {
+    Arena a = arena_create(1);
+    size_t tc; ErrorInfo lex_err = {0};
+    Token* toks = lex(&a,
+        "struct Point { x: i64, y: i64 } fn main() { let p: Point = Point { x: 10, y: true }; return; }",
+        "test", &tc, &lex_err);
+    ASSERT(toks != NULL);
+    ErrorInfo parse_err = {0};
+    AstNode* ast = parse(&a, toks, tc, "test", &parse_err);
+    ASSERT(ast != NULL);
+
+    ErrorList errors; error_init(&errors);
+    sema_analyze(ast, &errors, &a);
+    ASSERT(errors.count > 0);  // y 字段类型不匹配: true 是 bool, 不是 i64
+    arena_destroy(&a);
+}
+
+void test_struct_undefined() {
+    Arena a = arena_create(1);
+    size_t tc; ErrorInfo lex_err = {0};
+    Token* toks = lex(&a,
+        "fn main() { let p: Unknown = Unknown { x: 1 }; return; }",
+        "test", &tc, &lex_err);
+    ASSERT(toks != NULL);
+    ErrorInfo parse_err = {0};
+    AstNode* ast = parse(&a, toks, tc, "test", &parse_err);
+    ASSERT(ast != NULL);
+
+    ErrorList errors; error_init(&errors);
+    sema_analyze(ast, &errors, &a);
+    ASSERT(errors.count > 0);  // Unknown 未定义
+    arena_destroy(&a);
+}
+
+void test_struct_field_count_mismatch() {
+    Arena a = arena_create(1);
+    size_t tc; ErrorInfo lex_err = {0};
+    Token* toks = lex(&a,
+        "struct Point { x: i64, y: i64 } fn main() { let p: Point = Point { x: 10 }; return; }",
+        "test", &tc, &lex_err);
+    ASSERT(toks != NULL);
+    ErrorInfo parse_err = {0};
+    AstNode* ast = parse(&a, toks, tc, "test", &parse_err);
+    ASSERT(ast != NULL);
+
+    ErrorList errors; error_init(&errors);
+    sema_analyze(ast, &errors, &a);
+    ASSERT(errors.count > 0);  // 缺少字段 'y'
+    arena_destroy(&a);
+}
+
+void test_struct_nested_type_ok() {
+    Arena a = arena_create(1);
+    size_t tc; ErrorInfo lex_err = {0};
+    Token* toks = lex(&a,
+        "struct Point { x: i64, y: i64 } struct Rect { tl: Point, br: Point } fn main() { let r: Rect = Rect { tl: Point { x: 0, y: 0 }, br: Point { x: 1, y: 1 } }; print_i64(r.tl.x); return; }",
+        "test", &tc, &lex_err);
+    ASSERT(toks != NULL);
+    ErrorInfo parse_err = {0};
+    AstNode* ast = parse(&a, toks, tc, "test", &parse_err);
+    ASSERT(ast != NULL);
+
+    ErrorList errors; error_init(&errors);
+    sema_analyze(ast, &errors, &a);
+    ASSERT(errors.count == 0);  // 嵌套结构体类型检查应通过
+    arena_destroy(&a);
+}
+
 int main(void) {
     TEST_RUN(test_type_error);
     TEST_RUN(test_undefined_var);
@@ -123,5 +193,9 @@ int main(void) {
     TEST_RUN(test_assign_immutable_error);
     TEST_RUN(test_str_type_ok);
     TEST_RUN(test_str_concat_type_ok);
+    TEST_RUN(test_struct_field_type_mismatch);
+    TEST_RUN(test_struct_undefined);
+    TEST_RUN(test_struct_field_count_mismatch);
+    TEST_RUN(test_struct_nested_type_ok);
     return test_summary();
 }