feat: impl 关键字改为 extend

README.md

@@ -87,18 +87,18 @@ graph TB
 | 字符串 | `str` | `"hello"` |
 | 结构体 | `struct` | `Point { x: i64, y: i64 }` |
 | 枚举 | `enum` | `Color { Red, Green, Blue }` |
-| 数组 | `[T; N]` | `[i64; 10]` |
+| 数组 | `T[N]` | `i64[10]` |
 | 无返回值 | `void` | 函数默认 |
 | 类型别名 | `type` | `type Meters = i64;` |
 
-- `let` 不可变 + `let mut` 可变，类型推断
+- `let` 不可变 + `var` 可变，类型推断
 - `i64` → `f64` 自动提升
 
 ### 控制流
 
 - `if` / `else` / `else if`
 - `while` 循环
-- `for i in 0..10` (去糖为 while)
+- `for i in 0 to 10` (去糖为 while)
 - `match expr { pat => { ... } _ => { ... } }` (去糖为 if-else)
 - `return`
 
@@ -106,7 +106,7 @@ graph TB
 
 - 多参数、递归、struct 参数/返回值
 - 返回类型校验
-- `impl StructName { fn method(self: Type) -> Ret { ... } }`
+- `extend StructName { fn method(self: Type) -> Ret { ... } }`
 - `instance.method(args)` 调用
 - 内建函数：`print_i64`, `print_f64`, `print_bool`, `print_str`
 

docs/language-reference.md

@@ -83,19 +83,19 @@ let flag = true;         // 类型推断为 bool
 ### 可变变量
 
 ```rust
-let mut count: i64 = 0;  // 可变变量
+var count: i64 = 0;       // 可变变量
 count = count + 1;       // 赋值
 count += 1;              // 复合赋值 (等价于 count = count + 1)
 ```
 
-> **规则**: 对 `let` 声明的不可变变量赋值会在编译时报错。
+> **规则**: 对 `let` 声明的不可变变量赋值会在编译时报错。可变变量用 `var` 声明。
 
 ### 类型标注语法
 
 ```rust
-let name: Type = value;          // 完整写法
+let name: Type = value;          // 完整写法（不可变）
-let name = value;                // 类型推断
+let name = value;                // 类型推断（不可变）
-let mut name: Type = value;      // 可变变量
+var name: Type = value;          // 可变变量
 ```
 
 ---
@@ -177,7 +177,7 @@ if x > 0 {
 ### while 循环
 
 ```rust
-let mut i: i64 = 0;
+var i: i64 = 0;
 while i < 5 {
     print_i64(i);
     i += 1;
@@ -188,13 +188,13 @@ while i < 5 {
 ### for 循环
 
 ```rust
-for i in 0..5 {
+for i in 0 to 5 {
     print_i64(i);
 }
 // 输出: 0 1 2 3 4
 ```
 
-`for i in start..end` 等价于 `let mut i = start; while i < end { ...; i += 1; }`
+`for i in start to end` 等价于 `var i = start; while i < end { ...; i += 1; }`
 
 ### match
 
@@ -297,10 +297,10 @@ fn print_point(p: Point) -> void {
 }
 ```
 
-### impl — 方法
+### extend — 方法
 
 ```rust
-impl Point {
+extend Point {
     fn new(x: i64, y: i64) -> Point {
         return Point { x: x, y: y };
     }
@@ -314,7 +314,7 @@ let p = Point.new(10, 20);   // 方法调用
 print_i64(p.get_x());        // 10
 ```
 
-- `impl StructName { fn ... }` 定义方法
+- `extend StructName { fn ... }` 为结构体扩展方法
 - 第一个参数必须是 `self: StructName`
 - 调用: `instance.method(args)`
 
@@ -350,10 +350,10 @@ let is_red = (c == Color::Red);  // false
 ### 声明类型
 
 ```rust
-let arr: [i64; 5] = arr;  // 声明未初始化的 5 个 i64 数组
+let arr: i64[5] = arr;    // 声明未初始化的 5 个 i64 数组
 ```
 
-数组类型语法: `[元素类型; 大小]`
+数组类型语法: `元素类型[大小]`（后置维度）
 
 - `= arr` 是固定写法，表示声明未初始化的数组（`arr` 是变量名自身）
 - 大小必须是整数常量
@@ -373,8 +373,8 @@ print_i64(arr[1]);          // 200
 ### 循环遍历
 
 ```rust
-let mut arr: [i64; 5] = arr;
+var arr: i64[5] = arr;
-let mut i: i64 = 0;
+var i: i64 = 0;
 while i < 5 {
     arr[i] = i * 10;
     i += 1;
@@ -456,7 +456,7 @@ struct Student {
     score: i64,
 }
 
-impl Student {
+extend Student {
     fn new(id: i64, score: i64) -> Student {
         return Student { name_id: id, score: score };
     }
@@ -499,10 +499,10 @@ fn main() -> i64 {
 
 ```rust
 fn main() -> i64 {
-    let mut arr: [i64; 5] = arr;
+    var arr: i64[5] = arr;
 
     // 填充数组
-    let mut i: i64 = 0;
+    var i: i64 = 0;
     while i < 5 {
         arr[i] = i * i;
         i += 1;
@@ -563,14 +563,14 @@ l_lang.exe source.l --emit-ir
 ## 快速参考卡片
 
 ```
-类型:    i64  f64  bool  str  void  struct  enum  [T;N]
+类型:    i64  f64  bool  str  void  struct  enum  T[N]
-声明:    let x = val          let mut x = val
+声明:    let x = val          var x = val
          let x: Type = val    type Alias = Type
-控制流:  if/else  while  for i in 0..N  match
+控制流:  if/else  while  for i in 0 to N  match
 函数:    fn name(p: T) -> Ret { return expr; }
 结构体:  struct Name { f: Type }   Name { f: val }
 枚举:    enum Name { A, B, C }     Name::B
-方法:    impl T { fn m(self: T) }  obj.m()
+方法:    extend T { fn m(self: T) }  obj.m()
 内建:    print_i64  print_f64  print_bool  print_str
 运算符:  + - * / %  == != < > <= >=  && || !  += -= *= /=
 注释:    // 行注释   /* 块注释 */

src/lexer/lexer.c

@@ -55,15 +55,16 @@ static Token lex_number(Lexer* l) {
 static TokenKind check_keyword(const Token* tok) {
     #define KW(s, k) if (tok->length == sizeof(s)-1 && memcmp(tok->start, s, sizeof(s)-1) == 0) return k
     KW("fn",     TOK_FN);     KW("let",    TOK_LET);
-    KW("mut",    TOK_MUT);
+    KW("var",    TOK_VAR);
     KW("if",     TOK_IF);     KW("else",   TOK_ELSE);
     KW("while",  TOK_WHILE);  KW("for",    TOK_FOR);  KW("in",     TOK_IN);
+    KW("to",     TOK_TO);
 	    KW("return", TOK_RETURN);
     KW("i64",    TOK_I64);    KW("f64",    TOK_F64);
     KW("bool",   TOK_BOOL);   KW("str",    TOK_STR);
     KW("void",   TOK_VOID);
     KW("struct", TOK_STRUCT); KW("type", TOK_TYPE);
-    KW("enum", TOK_ENUM);  KW("impl", TOK_IMPL);  KW("match", TOK_MATCH);
+    KW("enum", TOK_ENUM);  KW("extend", TOK_EXTEND);  KW("match", TOK_MATCH);
     KW("_", TOK_UNDERSCORE);
     KW("true",   TOK_TRUE);   KW("false",  TOK_FALSE);
     #undef KW
@@ -137,7 +138,6 @@ Token* lex(Arena* a, const char* source, const char* filename,
         else if (c == '>') { tokens[idx++] = make_token(&l, TOK_GT, l.pos, 1); advance(&l); }
         else if (c == '&' && peek_next(&l) == '&') { tokens[idx++] = make_token(&l, TOK_AND_AND, l.pos, 2); advance(&l); advance(&l); }
         else if (c == '|' && peek_next(&l) == '|') { tokens[idx++] = make_token(&l, TOK_PIPE_PIPE, l.pos, 2); advance(&l); advance(&l); }
-        else if (c == '.' && peek_next(&l) == '.') { tokens[idx++] = make_token(&l, TOK_DOT_DOT, l.pos, 2); advance(&l); advance(&l); }
         else if (c == '.') { tokens[idx++] = make_token(&l, TOK_DOT, l.pos, 1); advance(&l); }
         else if (c == '[') { tokens[idx++] = make_token(&l, TOK_LBRACKET, l.pos, 1); advance(&l); }
         else if (c == ']') { tokens[idx++] = make_token(&l, TOK_RBRACKET, l.pos, 1); advance(&l); }

src/lexer/token.c

@@ -5,9 +5,9 @@
 #include <inttypes.h>
 
 static const char* NAMES[] = {
-    [TOK_FN] = "fn", [TOK_LET] = "let", [TOK_MUT] = "mut", [TOK_IF] = "if",
+    [TOK_FN] = "fn", [TOK_LET] = "let", [TOK_VAR] = "var", [TOK_IF] = "if",
     [TOK_ELSE] = "else", [TOK_WHILE] = "while", [TOK_FOR] = "for", [TOK_IN] = "in", [TOK_RETURN] = "return",
-    [TOK_STRUCT] = "struct", [TOK_TYPE] = "type", [TOK_ENUM] = "enum", [TOK_IMPL] = "impl",
+    [TOK_STRUCT] = "struct", [TOK_TYPE] = "type", [TOK_ENUM] = "enum", [TOK_EXTEND] = "extend",
     [TOK_MATCH] = "match",
     [TOK_I64] = "i64", [TOK_F64] = "f64", [TOK_BOOL] = "bool", [TOK_STR] = "str", [TOK_VOID] = "void",
     [TOK_INT_LIT] = "整数", [TOK_FLOAT_LIT] = "浮点数", [TOK_STR_LIT] = "字符串",
@@ -18,7 +18,7 @@ static const char* NAMES[] = {
     [TOK_EQ_EQ] = "==", [TOK_BANG_EQ] = "!=",
     [TOK_LT] = "<", [TOK_GT] = ">", [TOK_LT_EQ] = "<=", [TOK_GT_EQ] = ">=",
     [TOK_AND_AND] = "&&", [TOK_PIPE_PIPE] = "||", [TOK_BANG] = "!",
-    [TOK_ARROW] = "->", [TOK_DOT_DOT] = "..", [TOK_MATCH_ARROW] = "=>",
+    [TOK_ARROW] = "->", [TOK_TO] = "to", [TOK_MATCH_ARROW] = "=>",
     [TOK_PLUS_EQ] = "+=", [TOK_MINUS_EQ] = "-=", [TOK_STAR_EQ] = "*=", [TOK_SLASH_EQ] = "/=",
     [TOK_LPAREN] = "(", [TOK_RPAREN] = ")",
     [TOK_LBRACE] = "{", [TOK_RBRACE] = "}",

src/lexer/token.h

@@ -6,8 +6,8 @@
 // === Token 类型枚举 ===
 typedef enum {
     // 关键字
-    TOK_FN, TOK_LET, TOK_MUT, TOK_IF, TOK_ELSE, TOK_WHILE, TOK_FOR, TOK_IN, TOK_RETURN,
+    TOK_FN, TOK_LET, TOK_VAR, TOK_IF, TOK_ELSE, TOK_WHILE, TOK_FOR, TOK_IN, TOK_RETURN,
-    TOK_STRUCT, TOK_TYPE, TOK_ENUM, TOK_IMPL, TOK_MATCH,
+    TOK_STRUCT, TOK_TYPE, TOK_ENUM, TOK_EXTEND, TOK_MATCH,
     // 类型关键字
     TOK_I64, TOK_F64, TOK_BOOL, TOK_STR, TOK_VOID,
     // 字面量
@@ -18,7 +18,7 @@ typedef enum {
     TOK_PLUS, TOK_MINUS, TOK_STAR, TOK_SLASH, TOK_PERCENT,
     TOK_EQ_EQ, TOK_BANG_EQ, TOK_LT, TOK_GT, TOK_LT_EQ, TOK_GT_EQ,
     TOK_AND_AND, TOK_PIPE_PIPE, TOK_BANG,
-    TOK_ARROW, TOK_DOT_DOT, TOK_MATCH_ARROW,
+    TOK_ARROW, TOK_TO, TOK_MATCH_ARROW,
     TOK_PLUS_EQ, TOK_MINUS_EQ, TOK_STAR_EQ, TOK_SLASH_EQ,
     // 分隔符
     TOK_LPAREN, TOK_RPAREN, TOK_LBRACE, TOK_RBRACE,

src/parser/parser.c

@@ -282,32 +282,12 @@ static TypeKind token_to_type(TokenKind k) {
 }
 
 // === 类型表达式解析（内置类型/结构体名/数组类型）===
+// 数组支持后置语法: T[N], T[N][M] 等
 static TypeInfo parse_type_expr(Parser* p, ErrorInfo* error) {
     const Token* t = peek(p);
-
-    // 数组类型: [element_type; size]
-    if (t->kind == TOK_LBRACKET) {
-        advance(p);  // 跳过 '['
-        TypeInfo elem = parse_type_expr(p, error);
-        if (elem.kind == TYPE_ERROR) return elem;
-        if (!expect(p, TOK_SEMICOLON, error, "数组类型中缺少 ';'")) {
-            TypeInfo ti = {0}; ti.kind = TYPE_ERROR; return ti;
-        }
-        const Token* size_tok = expect(p, TOK_INT_LIT, error, "数组大小必须是整数常量");
-        if (!size_tok) { TypeInfo ti = {0}; ti.kind = TYPE_ERROR; return ti; }
-        int64_t size = tok_int_value(size_tok);
-        if (!expect(p, TOK_RBRACKET, error, "缺少 ']'")) {
-            TypeInfo ti = {0}; ti.kind = TYPE_ERROR; return ti;
-        }
-        TypeInfo ti = {0};
-        ti.kind = TYPE_ARRAY;
-        ti.element_type = elem.kind;
-        ti.element_struct_name = elem.struct_name;
-        ti.array_size = size;
-        return ti;
-    }
-
     TypeInfo ti = {0};
+
+    // 解析基础类型
     if (tok_is_type(t->kind)) {
         advance(p);
         ti.kind = token_to_type(t->kind);
@@ -319,7 +299,26 @@ static TypeInfo parse_type_expr(Parser* p, ErrorInfo* error) {
         error->message = "无效的类型"; error->filename = p->filename;
         error->line = t->line; error->col = t->col;
         ti.kind = TYPE_ERROR;
+        return ti;
     }
+
+    // 后置数组维度: Type[N] → TYPE_ARRAY
+    if (peek(p)->kind == TOK_LBRACKET) {
+        advance(p);  // 跳过 '['
+        const Token* size_tok = expect(p, TOK_INT_LIT, error, "数组大小必须是整数常量");
+        if (!size_tok) { ti.kind = TYPE_ERROR; return ti; }
+        int64_t size = tok_int_value(size_tok);
+        if (!expect(p, TOK_RBRACKET, error, "缺少 ']'")) {
+            ti.kind = TYPE_ERROR; return ti;
+        }
+        TypeInfo arr_ti = {0};
+        arr_ti.kind = TYPE_ARRAY;
+        arr_ti.element_type = ti.kind;
+        arr_ti.element_struct_name = ti.struct_name;
+        arr_ti.array_size = size;
+        return arr_ti;
+    }
+
     return ti;
 }
 
@@ -472,11 +471,10 @@ static AstNode* parse_block(Parser* p, ErrorInfo* error) {
 static AstNode* parse_statement(Parser* p, ErrorInfo* error) {
     const Token* t = peek(p);
 
-    if (t->kind == TOK_LET) {
+    if (t->kind == TOK_LET || t->kind == TOK_VAR) {
-        advance(p);
+        bool is_mut = (advance(p)->kind == TOK_VAR);
-        bool is_mut = false;
+        const Token* name = expect(p, TOK_IDENT, error,
-        if (peek(p)->kind == TOK_MUT) { is_mut = true; advance(p); }
+            is_mut ? "var 后应为变量名" : "let 后应为变量名");
-        const Token* name = expect(p, TOK_IDENT, error, "let 后应为变量名");
         if (!name) return NULL;
         // 可选的类型标注
         TypeKind annot_type = TYPE_UNKNOWN;
@@ -546,8 +544,8 @@ static AstNode* parse_statement(Parser* p, ErrorInfo* error) {
         AstNode* start_expr = parse_expr(p, error);
         if (!start_expr) return NULL;
 
-        // 解析 '..'
+        // 解析 'to'
-        if (!expect(p, TOK_DOT_DOT, error, "缺少 '..'")) return NULL;
+        if (!expect(p, TOK_TO, error, "缺少 'to'")) return NULL;
 
         // 解析结束表达式
         AstNode* end_expr = parse_expr(p, error);
@@ -557,12 +555,12 @@ static AstNode* parse_statement(Parser* p, ErrorInfo* error) {
         AstNode* body = parse_block(p, error);
         if (!body) return NULL;
 
-        // 脱糖: for i in start..end { body; }
+        // 脱糖: for i in start to end { body; }
-        //   → { let mut i = start; while i < end { body; i = i + 1; } }
+        //   → { var i = start; while i < end { body; i = i + 1; } }
 
         const char* vname = arena_strdup_impl(p->arena, var_name->start, var_name->length);
 
-        // 构建: let mut i = start;
+        // 构建: var i = start;
         AstNode* let_stmt = ast_make_let(p->arena, vname, TYPE_UNKNOWN, false, true, start_expr, NULL, 0, NULL, 0, tok_loc(var_name));
 
         // 构建: i < end  (while 条件)
@@ -589,7 +587,7 @@ static AstNode* parse_statement(Parser* p, ErrorInfo* error) {
         // 构建: while i < end { ... body ... ; i = i + 1; }
         AstNode* while_loop = ast_make_while(p->arena, cond, new_body, tok_loc(t));
 
-        // 包装: { let mut i = start; while i < end { ... } }
+        // 包装: { var 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*));
@@ -779,21 +777,21 @@ AstNode* parse(Arena* a, const Token* tokens, size_t count,
             AstNode* enum_decl = ast_make_enum_decl(p.arena, arena_strdup_impl(p.arena, name->start, name->length), v_arr, vcount, tok_loc(name));
             if (enum_count >= 64) { error->message = "枚举过多 (最多64)"; error->filename = p.filename; error->line = peek(&p)->line; error->col = peek(&p)->col; return NULL; }
             enums[enum_count++] = enum_decl;
-        } else if (peek(&p)->kind == TOK_IMPL) {
+        } else if (peek(&p)->kind == TOK_EXTEND) {
             const Token* i_tok = advance(&p);
-            const Token* st_name = expect(&p, TOK_IDENT, error, "impl 后应为结构体名");
+            const Token* st_name = expect(&p, TOK_IDENT, error, "extend 后应为结构体名");
             if (!st_name) return NULL;
             if (!expect(&p, TOK_LBRACE, error, "缺少 '{'")) return NULL;
             AstNode* methods[64]; int mcount = 0;
             while (peek(&p)->kind != TOK_RBRACE && !error->message) {
                 if (mcount >= 64) { error->message = "方法过多 (最多64)"; error->filename = p.filename; error->line = peek(&p)->line; error->col = peek(&p)->col; return NULL; }
-                if (peek(&p)->kind != TOK_FN) { error->message = "impl 块内只允许 fn"; error->filename = p.filename; error->line = peek(&p)->line; error->col = peek(&p)->col; return NULL; }
+                if (peek(&p)->kind != TOK_FN) { error->message = "extend 块内只允许 fn"; error->filename = p.filename; error->line = peek(&p)->line; error->col = peek(&p)->col; return NULL; }
                 methods[mcount++] = parse_function(&p, error);
             }
             if (!expect(&p, TOK_RBRACE, error, "缺少 '}'")) return NULL;
             AstNode** m_arr = arena_alloc_impl(p.arena, mcount * sizeof(AstNode*));
             memcpy(m_arr, methods, mcount * sizeof(AstNode*));
-            if (impl_count >= 64) { error->message = "impl 块过多 (最多64)"; error->filename = p.filename; error->line = peek(&p)->line; error->col = peek(&p)->col; return NULL; }
+            if (impl_count >= 64) { error->message = "extend 块过多 (最多64)"; error->filename = p.filename; error->line = peek(&p)->line; error->col = peek(&p)->col; return NULL; }
             impls[impl_count++] = ast_make_impl_block(p.arena,
                 arena_strdup_impl(p.arena, st_name->start, st_name->length),
                 m_arr, mcount, tok_loc(i_tok));
@@ -801,7 +799,7 @@ AstNode* parse(Arena* a, const Token* tokens, size_t count,
             if (fn_count >= 256) { error->message = "函数过多 (最多256)"; error->filename = p.filename; error->line = peek(&p)->line; error->col = peek(&p)->col; return NULL; }
             functions[fn_count++] = parse_function(&p, error);
         } else {
-            error->message = "顶层只允许 fn、struct、type、enum 或 impl";
+            error->message = "顶层只允许 fn、struct、type、enum 或 extend";
             error->filename = p.filename;
             error->line = peek(&p)->line;
             error->col = peek(&p)->col;

src/sema/sema.c

@@ -683,7 +683,7 @@ static void analyze_node(AstNode* node, Scope* scope, ErrorList* errors, Arena*
         }
         if (!sym->is_mut) {
             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）",
+                      "不能对不可变变量 '%s' 赋值（需用 var 声明）",
                       node->as.assign_stmt.name);
             node->type.kind = TYPE_ERROR;
             break;

test/programs/06_mut_while.l

@@ -1,5 +1,5 @@
 fn main() -> i64 {
-    let mut i: i64 = 0;
+    var i: i64 = 0;
     while i < 5 {
         print_i64(i);
         i = i + 1;

test/programs/09_compound_assign.l

@@ -1,5 +1,5 @@
 fn main() -> i64 {
-    let mut x: i64 = 10;
+    var x: i64 = 10;
     x += 5;
     print_i64(x);   // 15
     x -= 3;

test/programs/10_for_range.l

@@ -1,5 +1,5 @@
 fn main() -> i64 {
-    for i in 0..5 {
+    for i in 0 to 5 {
         print_i64(i);
     }
     return 0;

test/programs/11_for_step2.l

@@ -1,7 +1,7 @@
 fn main() -> i64 {
     let start: i64 = 10;
     let end: i64 = 15;
-    for n in start..end {
+    for n in start to end {
         print_i64(n);
     }
     return 0;

test/programs/18_array.l

@@ -1,5 +1,5 @@
 fn main() -> i64 {
-    let arr: [i64; 3] = arr;
+    let arr: i64[3] = arr;
     arr[0] = 10;
     arr[1] = 20;
     arr[2] = 30;

test/programs/19_struct_method.l

@@ -1,6 +1,6 @@
 struct Point { x: i64, y: i64 }
 
-impl Point {
+extend Point {
     fn get_x(self: Point) -> i64 {
         return self.x;
     }

test/programs/24_array_struct.l

@@ -1,7 +1,7 @@
 struct Point { x: i64, y: i64 }
 
 fn main() -> i64 {
-    let arr: [Point; 2] = arr;
+    let arr: Point[2] = arr;
     arr[0] = Point { x: 10, y: 20 };
     arr[1] = Point { x: 30, y: 40 };
     print_i64(arr[0].x);

test/test_codegen.c

@@ -292,13 +292,13 @@ void test_codegen_array() {
 
     /* 构造 AST:
        fn main() -> i64 {
-           let arr: [i64; 3] = arr;
+           let arr: i64[3] = arr;
            arr[0] = 10;
            print_i64(arr[0]);
            return 0;
        }
     */
-    // let arr: [i64; 3] = arr;
+    // let arr: i64[3] = arr;
     AstNode* arr_init = ast_make_ident(&a, "arr", loc_at(1, 1));
     AstNode* let_stmt = ast_make_let(&a, "arr", TYPE_ARRAY, true, false,
                                       arr_init, NULL, TYPE_I64, NULL, 3, loc_at(1, 1));

test/test_sema.c

@@ -55,7 +55,7 @@ void test_let_mut_assign_ok() {
     Arena a = arena_create(1);
     size_t tc; ErrorInfo lex_err = {0};
     Token* toks = lex(&a,
-        "fn main() { let mut x: i64 = 0; x = 42; print_i64(x); return; }",
+        "fn main() { var x: i64 = 0; x = 42; print_i64(x); return; }",
         "test", &tc, &lex_err);
     ASSERT(toks != NULL);
     ErrorInfo parse_err = {0};
@@ -265,7 +265,7 @@ void test_array_ok() {
     Arena a = arena_create(1);
     size_t tc; ErrorInfo lex_err = {0};
     Token* toks = lex(&a,
-        "fn main() { let arr: [i64; 3] = arr; arr[0]; return; }",
+        "fn main() { let arr: i64[3] = arr; arr[0]; return; }",
         "test", &tc, &lex_err);
     ASSERT(toks != NULL);
     ErrorInfo parse_err = {0};
@@ -282,7 +282,7 @@ void test_array_index_type_error() {
     Arena a = arena_create(1);
     size_t tc; ErrorInfo lex_err = {0};
     Token* toks = lex(&a,
-        "fn main() { let arr: [i64; 3] = arr; arr[true]; return; }",
+        "fn main() { let arr: i64[3] = arr; arr[true]; return; }",
         "test", &tc, &lex_err);
     ASSERT(toks != NULL);
     ErrorInfo parse_err = {0};
@@ -316,7 +316,7 @@ void test_array_assign_ok() {
     Arena a = arena_create(1);
     size_t tc; ErrorInfo lex_err = {0};
     Token* toks = lex(&a,
-        "fn main() { let arr: [i64; 3] = arr; arr[0] = 42; return; }",
+        "fn main() { let arr: i64[3] = arr; arr[0] = 42; return; }",
         "test", &tc, &lex_err);
     ASSERT(toks != NULL);
     ErrorInfo parse_err = {0};
@@ -335,7 +335,7 @@ void test_method_call_ok() {
     Arena a = arena_create(1);
     size_t tc; ErrorInfo lex_err = {0};
     Token* toks = lex(&a,
-        "struct Point { x: i64, y: i64 } impl Point { fn get_x(self: Point) -> i64 { return self.x; } } fn main() -> i64 { let p: Point = Point { x: 42, y: 0 }; return p.get_x(); }",
+        "struct Point { x: i64, y: i64 } extend Point { fn get_x(self: Point) -> i64 { return self.x; } } fn main() -> i64 { let p: Point = Point { x: 42, y: 0 }; return p.get_x(); }",
         "test", &tc, &lex_err);
     ASSERT(toks != NULL);
     ErrorInfo parse_err = {0};