diff --git a/tests/README.md b/tests/README.md
index 8246209..630b834 100644
--- a/tests/README.md
+++ b/tests/README.md
@@ -4,6 +4,16 @@
 
 可以 `add_test` 调 `STCompiler` / `BytecodeExecutor`（编译→执行管线），或直接链接 `compiler` + `vm` 做单元断言。样例工程数据按「一份 toml + 若干 `.st`」分子目录存放，不要做成 library。
 
+## 用例目录（`cases/`）
+
+每个用例一个子目录：`project.toml` + `.st` + `EXPECTED.md`（期望：通过 / 报哪类错）。清单与编号见 [`Doc/初步计划.md`](../Doc/初步计划.md) 12.2 节，共 20 个：
+
+- 正例：01 空 MAIN、02 BOOL、03 短路、04 IF、05 WHILE、07 算术、08 TIME、09 GVL+EXTERNAL、13 FUNCTION、15 FB、17 TON、18 TOF/CTU、20 line1
+- 负例（编译错误/链接失败）：10 非 GVL 写全局、11 同名全局、12 io.var 未声明、14 FUNCTION 写全局、16 未声明实例、19 循环调用
+- 运行时故障：06 cycle_limit 打满
+
+12.2 完成标准：目录和期望表齐，此时大部分还编不过，属正常。实现阶段逐个点亮。
+
 ## 第一版要冻的
 
 - 关键字表与约 20 个样例程序
diff --git a/tests/cases/01_empty_main/EXPECTED.md b/tests/cases/01_empty_main/EXPECTED.md
new file mode 100644
index 0000000..f89b6a0
--- /dev/null
+++ b/tests/cases/01_empty_main/EXPECTED.md
@@ -0,0 +1,4 @@
+# 期望：编译通过
+
+- 映像：MAIN（fn_id=0）字节码为一条 `RET`，`nregs=0`
+- 运行任意周期数无故障
diff --git a/tests/cases/01_empty_main/main.st b/tests/cases/01_empty_main/main.st
new file mode 100644
index 0000000..abb17ed
--- /dev/null
+++ b/tests/cases/01_empty_main/main.st
@@ -0,0 +1,2 @@
+PROGRAM MAIN
+END_PROGRAM
diff --git a/tests/cases/01_empty_main/project.toml b/tests/cases/01_empty_main/project.toml
new file mode 100644
index 0000000..46b4e3b
--- /dev/null
+++ b/tests/cases/01_empty_main/project.toml
@@ -0,0 +1,8 @@
+[project]
+name = "case01"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["main.st"]
diff --git a/tests/cases/02_bool_assign/EXPECTED.md b/tests/cases/02_bool_assign/EXPECTED.md
new file mode 100644
index 0000000..775f938
--- /dev/null
+++ b/tests/cases/02_bool_assign/EXPECTED.md
@@ -0,0 +1,4 @@
+# 期望：编译通过
+
+- 执行后 `a` = TRUE、`b` = FALSE
+- `TRUE` / `FALSE` 是关键字，不是标识符
diff --git a/tests/cases/02_bool_assign/main.st b/tests/cases/02_bool_assign/main.st
new file mode 100644
index 0000000..570f321
--- /dev/null
+++ b/tests/cases/02_bool_assign/main.st
@@ -0,0 +1,8 @@
+PROGRAM MAIN
+VAR
+    a : BOOL;
+    b : BOOL;
+END_VAR
+    a := TRUE;
+    b := FALSE;
+END_PROGRAM
diff --git a/tests/cases/02_bool_assign/project.toml b/tests/cases/02_bool_assign/project.toml
new file mode 100644
index 0000000..96dbd78
--- /dev/null
+++ b/tests/cases/02_bool_assign/project.toml
@@ -0,0 +1,8 @@
+[project]
+name = "case02"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["main.st"]
diff --git a/tests/cases/03_short_circuit/EXPECTED.md b/tests/cases/03_short_circuit/EXPECTED.md
new file mode 100644
index 0000000..553b8e5
--- /dev/null
+++ b/tests/cases/03_short_circuit/EXPECTED.md
@@ -0,0 +1,4 @@
+# 期望：编译通过
+
+- 反汇编中 `AND` / `OR` 必须编成条件跳转（`JT` / `JF`），不得先算两侧再组合
+- v1 表达式无调用、无副作用；「右侧有副作用时不执行」以编译产物含条件跳转为验收标准
diff --git a/tests/cases/03_short_circuit/main.st b/tests/cases/03_short_circuit/main.st
new file mode 100644
index 0000000..7af35e7
--- /dev/null
+++ b/tests/cases/03_short_circuit/main.st
@@ -0,0 +1,9 @@
+PROGRAM MAIN
+VAR
+    a : BOOL;
+    b : BOOL;
+    x : BOOL;
+END_VAR
+    x := a AND b;
+    x := a OR b;
+END_PROGRAM
diff --git a/tests/cases/03_short_circuit/project.toml b/tests/cases/03_short_circuit/project.toml
new file mode 100644
index 0000000..6c28ffc
--- /dev/null
+++ b/tests/cases/03_short_circuit/project.toml
@@ -0,0 +1,8 @@
+[project]
+name = "case03"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["main.st"]
diff --git a/tests/cases/04_if_elsif_else/EXPECTED.md b/tests/cases/04_if_elsif_else/EXPECTED.md
new file mode 100644
index 0000000..d7abe9d
--- /dev/null
+++ b/tests/cases/04_if_elsif_else/EXPECTED.md
@@ -0,0 +1,4 @@
+# 期望：编译通过
+
+- `sel` = 0 → `out` = 10；`sel` = 1 → `out` = 20；其他 → `out` = 30
+- 必须编成比较 + 条件跳转，不逐分支执行
diff --git a/tests/cases/04_if_elsif_else/main.st b/tests/cases/04_if_elsif_else/main.st
new file mode 100644
index 0000000..ddf2cd3
--- /dev/null
+++ b/tests/cases/04_if_elsif_else/main.st
@@ -0,0 +1,13 @@
+PROGRAM MAIN
+VAR
+    sel : INT;
+    out : INT;
+END_VAR
+    IF sel = 0 THEN
+        out := 10;
+    ELSIF sel = 1 THEN
+        out := 20;
+    ELSE
+        out := 30;
+    END_IF
+END_PROGRAM
diff --git a/tests/cases/04_if_elsif_else/project.toml b/tests/cases/04_if_elsif_else/project.toml
new file mode 100644
index 0000000..39d6878
--- /dev/null
+++ b/tests/cases/04_if_elsif_else/project.toml
@@ -0,0 +1,8 @@
+[project]
+name = "case04"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["main.st"]
diff --git a/tests/cases/05_while_normal/EXPECTED.md b/tests/cases/05_while_normal/EXPECTED.md
new file mode 100644
index 0000000..a73f4f9
--- /dev/null
+++ b/tests/cases/05_while_normal/EXPECTED.md
@@ -0,0 +1,3 @@
+# 期望：编译通过
+
+- 循环结束后 `n` = 10（正常终止，不触发 cycle_limit）
diff --git a/tests/cases/05_while_normal/main.st b/tests/cases/05_while_normal/main.st
new file mode 100644
index 0000000..90ea81c
--- /dev/null
+++ b/tests/cases/05_while_normal/main.st
@@ -0,0 +1,9 @@
+PROGRAM MAIN
+VAR
+    n : INT;
+END_VAR
+    n := 0;
+    WHILE n < 10 DO
+        n := n + 1;
+    END_WHILE
+END_PROGRAM
diff --git a/tests/cases/05_while_normal/project.toml b/tests/cases/05_while_normal/project.toml
new file mode 100644
index 0000000..2af69b3
--- /dev/null
+++ b/tests/cases/05_while_normal/project.toml
@@ -0,0 +1,8 @@
+[project]
+name = "case05"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["main.st"]
diff --git a/tests/cases/06_while_cycle_limit/EXPECTED.md b/tests/cases/06_while_cycle_limit/EXPECTED.md
new file mode 100644
index 0000000..e73793a
--- /dev/null
+++ b/tests/cases/06_while_cycle_limit/EXPECTED.md
@@ -0,0 +1,4 @@
+# 期望：运行时故障
+
+- 单周期指令数超 `cycle_limit = 10`，VM 报故障并停止
+- 编译本身通过；WHILE 不做终止证明
diff --git a/tests/cases/06_while_cycle_limit/main.st b/tests/cases/06_while_cycle_limit/main.st
new file mode 100644
index 0000000..7c3f716
--- /dev/null
+++ b/tests/cases/06_while_cycle_limit/main.st
@@ -0,0 +1,4 @@
+PROGRAM MAIN
+    WHILE TRUE DO
+    END_WHILE
+END_PROGRAM
diff --git a/tests/cases/06_while_cycle_limit/project.toml b/tests/cases/06_while_cycle_limit/project.toml
new file mode 100644
index 0000000..6e5d23a
--- /dev/null
+++ b/tests/cases/06_while_cycle_limit/project.toml
@@ -0,0 +1,8 @@
+[project]
+name = "case06"
+entry = "program MAIN"
+cycle_limit = 10
+dt_ms = 10
+
+[files]
+st = ["main.st"]
diff --git a/tests/cases/07_int_arith/EXPECTED.md b/tests/cases/07_int_arith/EXPECTED.md
new file mode 100644
index 0000000..8f832e9
--- /dev/null
+++ b/tests/cases/07_int_arith/EXPECTED.md
@@ -0,0 +1,4 @@
+# 期望：编译通过
+
+- `a` = 42、`b` = 10、`c` = 32、`eq` = TRUE
+- 溢出饱和：`30000 + 30000` = 32767、`-30000 - 30000` = -32768（由 isa 饱和函数保证）
diff --git a/tests/cases/07_int_arith/main.st b/tests/cases/07_int_arith/main.st
new file mode 100644
index 0000000..0b140c9
--- /dev/null
+++ b/tests/cases/07_int_arith/main.st
@@ -0,0 +1,10 @@
+PROGRAM MAIN
+VAR
+    a, b, c : INT;
+    eq : BOOL;
+END_VAR
+    a := 7 * 6;
+    b := a / 4;
+    c := a - b;
+    eq := c > 30;
+END_PROGRAM
diff --git a/tests/cases/07_int_arith/project.toml b/tests/cases/07_int_arith/project.toml
new file mode 100644
index 0000000..c3a2005
--- /dev/null
+++ b/tests/cases/07_int_arith/project.toml
@@ -0,0 +1,8 @@
+[project]
+name = "case07"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["main.st"]
diff --git a/tests/cases/08_time_literal/EXPECTED.md b/tests/cases/08_time_literal/EXPECTED.md
new file mode 100644
index 0000000..3316c3d
--- /dev/null
+++ b/tests/cases/08_time_literal/EXPECTED.md
@@ -0,0 +1,4 @@
+# 期望：编译通过
+
+- `t1` = 10 毫秒、`t2` = 1250 毫秒（内部一律毫秒）
+- `TIME` 与 `INT` 不混用；不支持 `T#` 以外的 TIME 语法
diff --git a/tests/cases/08_time_literal/main.st b/tests/cases/08_time_literal/main.st
new file mode 100644
index 0000000..48f1d9e
--- /dev/null
+++ b/tests/cases/08_time_literal/main.st
@@ -0,0 +1,7 @@
+PROGRAM MAIN
+VAR
+    t1, t2 : TIME;
+END_VAR
+    t1 := T#10ms;
+    t2 := T#1s250ms;
+END_PROGRAM
diff --git a/tests/cases/08_time_literal/project.toml b/tests/cases/08_time_literal/project.toml
new file mode 100644
index 0000000..85aff37
--- /dev/null
+++ b/tests/cases/08_time_literal/project.toml
@@ -0,0 +1,8 @@
+[project]
+name = "case08"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["main.st"]
diff --git a/tests/cases/09_gvl_external/EXPECTED.md b/tests/cases/09_gvl_external/EXPECTED.md
new file mode 100644
index 0000000..540026d
--- /dev/null
+++ b/tests/cases/09_gvl_external/EXPECTED.md
@@ -0,0 +1,4 @@
+# 期望：编译通过
+
+- 符号表里 `G1` 的 global 与 external 指向**同一槽**，不是新变量
+- 执行后 `x` = 5（初值来自 GVL）
diff --git a/tests/cases/09_gvl_external/globals.st b/tests/cases/09_gvl_external/globals.st
new file mode 100644
index 0000000..8b63cbf
--- /dev/null
+++ b/tests/cases/09_gvl_external/globals.st
@@ -0,0 +1,3 @@
+VAR_GLOBAL
+    G1 : INT := 5;
+END_VAR
diff --git a/tests/cases/09_gvl_external/main.st b/tests/cases/09_gvl_external/main.st
new file mode 100644
index 0000000..e16974d
--- /dev/null
+++ b/tests/cases/09_gvl_external/main.st
@@ -0,0 +1,9 @@
+PROGRAM MAIN
+VAR_EXTERNAL
+    G1 : INT;
+END_VAR
+VAR
+    x : INT;
+END_VAR
+    x := G1;
+END_PROGRAM
diff --git a/tests/cases/09_gvl_external/project.toml b/tests/cases/09_gvl_external/project.toml
new file mode 100644
index 0000000..f7d30d1
--- /dev/null
+++ b/tests/cases/09_gvl_external/project.toml
@@ -0,0 +1,11 @@
+[project]
+name = "case09"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["globals.st", "main.st"]
+
+[gvl]
+file = "globals.st"
diff --git a/tests/cases/10_gvl_wrong_file/EXPECTED.md b/tests/cases/10_gvl_wrong_file/EXPECTED.md
new file mode 100644
index 0000000..e778bd8
--- /dev/null
+++ b/tests/cases/10_gvl_wrong_file/EXPECTED.md
@@ -0,0 +1,4 @@
+# 期望：编译错误
+
+- `other.st` 出现 `VAR_GLOBAL`，但 `gvl.file = globals.st`
+- 报错类别：VAR_GLOBAL 只允许出现在 gvl.file
diff --git a/tests/cases/10_gvl_wrong_file/globals.st b/tests/cases/10_gvl_wrong_file/globals.st
new file mode 100644
index 0000000..0fd7899
--- /dev/null
+++ b/tests/cases/10_gvl_wrong_file/globals.st
@@ -0,0 +1,3 @@
+VAR_GLOBAL
+    G1 : BOOL;
+END_VAR
diff --git a/tests/cases/10_gvl_wrong_file/other.st b/tests/cases/10_gvl_wrong_file/other.st
new file mode 100644
index 0000000..8ed700a
--- /dev/null
+++ b/tests/cases/10_gvl_wrong_file/other.st
@@ -0,0 +1,5 @@
+PROGRAM MAIN
+VAR_GLOBAL
+    G2 : BOOL;
+END_VAR
+END_PROGRAM
diff --git a/tests/cases/10_gvl_wrong_file/project.toml b/tests/cases/10_gvl_wrong_file/project.toml
new file mode 100644
index 0000000..8a0108f
--- /dev/null
+++ b/tests/cases/10_gvl_wrong_file/project.toml
@@ -0,0 +1,11 @@
+[project]
+name = "case10"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["globals.st", "other.st"]
+
+[gvl]
+file = "globals.st"
diff --git a/tests/cases/11_duplicate_global/EXPECTED.md b/tests/cases/11_duplicate_global/EXPECTED.md
new file mode 100644
index 0000000..c87a3b0
--- /dev/null
+++ b/tests/cases/11_duplicate_global/EXPECTED.md
@@ -0,0 +1,3 @@
+# 期望：链接失败
+
+- 同名 `VAR_GLOBAL`（G1）出现两次，禁止覆盖
diff --git a/tests/cases/11_duplicate_global/globals.st b/tests/cases/11_duplicate_global/globals.st
new file mode 100644
index 0000000..f89fdf4
--- /dev/null
+++ b/tests/cases/11_duplicate_global/globals.st
@@ -0,0 +1,7 @@
+VAR_GLOBAL
+    G1 : INT;
+END_VAR
+
+VAR_GLOBAL
+    G1 : INT;
+END_VAR
diff --git a/tests/cases/11_duplicate_global/main.st b/tests/cases/11_duplicate_global/main.st
new file mode 100644
index 0000000..abb17ed
--- /dev/null
+++ b/tests/cases/11_duplicate_global/main.st
@@ -0,0 +1,2 @@
+PROGRAM MAIN
+END_PROGRAM
diff --git a/tests/cases/11_duplicate_global/project.toml b/tests/cases/11_duplicate_global/project.toml
new file mode 100644
index 0000000..ed7fcbb
--- /dev/null
+++ b/tests/cases/11_duplicate_global/project.toml
@@ -0,0 +1,11 @@
+[project]
+name = "case11"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["globals.st", "main.st"]
+
+[gvl]
+file = "globals.st"
diff --git a/tests/cases/12_io_unknown_var/EXPECTED.md b/tests/cases/12_io_unknown_var/EXPECTED.md
new file mode 100644
index 0000000..6553fcb
--- /dev/null
+++ b/tests/cases/12_io_unknown_var/EXPECTED.md
@@ -0,0 +1,4 @@
+# 期望：编译错误
+
+- `[[io.input]]` 的 `var = "Nope"` 未在 GVL 声明
+- 报错类别：io.var 未在 GVL（io 不创造变量）
diff --git a/tests/cases/12_io_unknown_var/globals.st b/tests/cases/12_io_unknown_var/globals.st
new file mode 100644
index 0000000..0fd7899
--- /dev/null
+++ b/tests/cases/12_io_unknown_var/globals.st
@@ -0,0 +1,3 @@
+VAR_GLOBAL
+    G1 : BOOL;
+END_VAR
diff --git a/tests/cases/12_io_unknown_var/main.st b/tests/cases/12_io_unknown_var/main.st
new file mode 100644
index 0000000..abb17ed
--- /dev/null
+++ b/tests/cases/12_io_unknown_var/main.st
@@ -0,0 +1,2 @@
+PROGRAM MAIN
+END_PROGRAM
diff --git a/tests/cases/12_io_unknown_var/project.toml b/tests/cases/12_io_unknown_var/project.toml
new file mode 100644
index 0000000..87db796
--- /dev/null
+++ b/tests/cases/12_io_unknown_var/project.toml
@@ -0,0 +1,16 @@
+[project]
+name = "case12"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["globals.st", "main.st"]
+
+[gvl]
+file = "globals.st"
+
+[[io.input]]
+var = "Nope"
+channel = 0
+bit = 0
diff --git a/tests/cases/13_function_call/EXPECTED.md b/tests/cases/13_function_call/EXPECTED.md
new file mode 100644
index 0000000..0525049
--- /dev/null
+++ b/tests/cases/13_function_call/EXPECTED.md
@@ -0,0 +1,4 @@
+# 期望：编译通过
+
+- `CALL fn_id` + 有界调用帧；函数无内部状态
+- 执行后 `x` = 7；结果值 = 函数名赋值（`Add := ...`）
diff --git a/tests/cases/13_function_call/main.st b/tests/cases/13_function_call/main.st
new file mode 100644
index 0000000..32597f9
--- /dev/null
+++ b/tests/cases/13_function_call/main.st
@@ -0,0 +1,13 @@
+FUNCTION Add : INT
+VAR_INPUT
+    a, b : INT;
+END_VAR
+    Add := a + b;
+END_FUNCTION
+
+PROGRAM MAIN
+VAR
+    x : INT;
+END_VAR
+    x := Add(3, 4);
+END_PROGRAM
diff --git a/tests/cases/13_function_call/project.toml b/tests/cases/13_function_call/project.toml
new file mode 100644
index 0000000..a3a31a3
--- /dev/null
+++ b/tests/cases/13_function_call/project.toml
@@ -0,0 +1,8 @@
+[project]
+name = "case13"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["main.st"]
diff --git a/tests/cases/14_function_write_global/EXPECTED.md b/tests/cases/14_function_write_global/EXPECTED.md
new file mode 100644
index 0000000..c7b5913
--- /dev/null
+++ b/tests/cases/14_function_write_global/EXPECTED.md
@@ -0,0 +1,4 @@
+# 期望：编译错误
+
+- `FUNCTION` 内写全局（此处经 `VAR_EXTERNAL` 写 `G1`）
+- 报错类别：FUNCTION 禁止写全局
diff --git a/tests/cases/14_function_write_global/globals.st b/tests/cases/14_function_write_global/globals.st
new file mode 100644
index 0000000..ab85e9b
--- /dev/null
+++ b/tests/cases/14_function_write_global/globals.st
@@ -0,0 +1,3 @@
+VAR_GLOBAL
+    G1 : INT;
+END_VAR
diff --git a/tests/cases/14_function_write_global/main.st b/tests/cases/14_function_write_global/main.st
new file mode 100644
index 0000000..3612310
--- /dev/null
+++ b/tests/cases/14_function_write_global/main.st
@@ -0,0 +1,9 @@
+FUNCTION Bad : INT
+VAR_EXTERNAL
+    G1 : INT;
+END_VAR
+    G1 := 1;
+END_FUNCTION
+
+PROGRAM MAIN
+END_PROGRAM
diff --git a/tests/cases/14_function_write_global/project.toml b/tests/cases/14_function_write_global/project.toml
new file mode 100644
index 0000000..6089ead
--- /dev/null
+++ b/tests/cases/14_function_write_global/project.toml
@@ -0,0 +1,11 @@
+[project]
+name = "case14"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["globals.st", "main.st"]
+
+[gvl]
+file = "globals.st"
diff --git a/tests/cases/15_fb_instance/EXPECTED.md b/tests/cases/15_fb_instance/EXPECTED.md
new file mode 100644
index 0000000..5478127
--- /dev/null
+++ b/tests/cases/15_fb_instance/EXPECTED.md
@@ -0,0 +1,4 @@
+# 期望：编译通过
+
+- FB 实例固定布局，`starter.Q` 字段偏移编译期算死
+- 命名输入绑定 `start` / `stop`；执行后 `q` = TRUE
diff --git a/tests/cases/15_fb_instance/main.st b/tests/cases/15_fb_instance/main.st
new file mode 100644
index 0000000..087c1b1
--- /dev/null
+++ b/tests/cases/15_fb_instance/main.st
@@ -0,0 +1,8 @@
+PROGRAM MAIN
+VAR
+    starter : MotorStarter;
+    q : BOOL;
+END_VAR
+    starter(start := TRUE, stop := FALSE);
+    q := starter.Q;
+END_PROGRAM
diff --git a/tests/cases/15_fb_instance/motor.st b/tests/cases/15_fb_instance/motor.st
new file mode 100644
index 0000000..db037f9
--- /dev/null
+++ b/tests/cases/15_fb_instance/motor.st
@@ -0,0 +1,9 @@
+FUNCTION_BLOCK MotorStarter
+VAR_INPUT
+    start, stop : BOOL;
+END_VAR
+VAR_OUTPUT
+    Q : BOOL;
+END_VAR
+    Q := start AND NOT stop;
+END_FUNCTION_BLOCK
diff --git a/tests/cases/15_fb_instance/project.toml b/tests/cases/15_fb_instance/project.toml
new file mode 100644
index 0000000..e33b8b6
--- /dev/null
+++ b/tests/cases/15_fb_instance/project.toml
@@ -0,0 +1,8 @@
+[project]
+name = "case15"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["motor.st", "main.st"]
diff --git a/tests/cases/16_fb_undeclared/EXPECTED.md b/tests/cases/16_fb_undeclared/EXPECTED.md
new file mode 100644
index 0000000..76a94bc
--- /dev/null
+++ b/tests/cases/16_fb_undeclared/EXPECTED.md
@@ -0,0 +1,4 @@
+# 期望：编译错误
+
+- 调用 `starter(...)` 但未声明实例
+- 报错类别：FB 必须先声明实例才能调用
diff --git a/tests/cases/16_fb_undeclared/main.st b/tests/cases/16_fb_undeclared/main.st
new file mode 100644
index 0000000..f42d0cb
--- /dev/null
+++ b/tests/cases/16_fb_undeclared/main.st
@@ -0,0 +1,7 @@
+PROGRAM MAIN
+VAR
+    q : BOOL;
+END_VAR
+    starter(start := TRUE, stop := FALSE);
+    q := starter.Q;
+END_PROGRAM
diff --git a/tests/cases/16_fb_undeclared/motor.st b/tests/cases/16_fb_undeclared/motor.st
new file mode 100644
index 0000000..db037f9
--- /dev/null
+++ b/tests/cases/16_fb_undeclared/motor.st
@@ -0,0 +1,9 @@
+FUNCTION_BLOCK MotorStarter
+VAR_INPUT
+    start, stop : BOOL;
+END_VAR
+VAR_OUTPUT
+    Q : BOOL;
+END_VAR
+    Q := start AND NOT stop;
+END_FUNCTION_BLOCK
diff --git a/tests/cases/16_fb_undeclared/project.toml b/tests/cases/16_fb_undeclared/project.toml
new file mode 100644
index 0000000..19123fd
--- /dev/null
+++ b/tests/cases/16_fb_undeclared/project.toml
@@ -0,0 +1,8 @@
+[project]
+name = "case16"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["motor.st", "main.st"]
diff --git a/tests/cases/17_ton/EXPECTED.md b/tests/cases/17_ton/EXPECTED.md
new file mode 100644
index 0000000..b05ed8a
--- /dev/null
+++ b/tests/cases/17_ton/EXPECTED.md
@@ -0,0 +1,4 @@
+# 期望：编译通过；运行行为与 Δt 一致
+
+- `dt_ms = 10`、`PT = 30ms`：前 2 周期 `Q` = FALSE，第 3 周期起 `Q` = TRUE
+- 累计用映像里的 Δt，不用 wall clock
diff --git a/tests/cases/17_ton/main.st b/tests/cases/17_ton/main.st
new file mode 100644
index 0000000..4d7447b
--- /dev/null
+++ b/tests/cases/17_ton/main.st
@@ -0,0 +1,8 @@
+PROGRAM MAIN
+VAR
+    t : TON;
+    q : BOOL;
+END_VAR
+    t(in := TRUE, pt := T#30ms);
+    q := t.Q;
+END_PROGRAM
diff --git a/tests/cases/17_ton/project.toml b/tests/cases/17_ton/project.toml
new file mode 100644
index 0000000..2726f46
--- /dev/null
+++ b/tests/cases/17_ton/project.toml
@@ -0,0 +1,8 @@
+[project]
+name = "case17"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["main.st"]
diff --git a/tests/cases/18_tof_ctu/EXPECTED.md b/tests/cases/18_tof_ctu/EXPECTED.md
new file mode 100644
index 0000000..486bcb0
--- /dev/null
+++ b/tests/cases/18_tof_ctu/EXPECTED.md
@@ -0,0 +1,5 @@
+# 期望：编译通过；运行行为与 Δt 一致
+
+- TOF：`in` 掉电后 `Q` 保持 `PT` 时长（20ms）再复位
+- CTU：`cu` 上升沿计数 +1；`r` 复位；`CV` 到 `PV`（3）时 `Q` = TRUE
+- 内部累计用映像 Δt，不用 wall clock
diff --git a/tests/cases/18_tof_ctu/main.st b/tests/cases/18_tof_ctu/main.st
new file mode 100644
index 0000000..b3ab44a
--- /dev/null
+++ b/tests/cases/18_tof_ctu/main.st
@@ -0,0 +1,13 @@
+PROGRAM MAIN
+VAR
+    tf : TOF;
+    c : CTU;
+    q1, q2 : BOOL;
+    cnt : INT;
+END_VAR
+    tf(in := FALSE, pt := T#20ms);
+    q1 := tf.Q;
+    c(cu := TRUE, r := FALSE, pv := 3);
+    q2 := c.Q;
+    cnt := c.CV;
+END_PROGRAM
diff --git a/tests/cases/18_tof_ctu/project.toml b/tests/cases/18_tof_ctu/project.toml
new file mode 100644
index 0000000..37b21e6
--- /dev/null
+++ b/tests/cases/18_tof_ctu/project.toml
@@ -0,0 +1,8 @@
+[project]
+name = "case18"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["main.st"]
diff --git a/tests/cases/19_recursive_call/EXPECTED.md b/tests/cases/19_recursive_call/EXPECTED.md
new file mode 100644
index 0000000..608fa62
--- /dev/null
+++ b/tests/cases/19_recursive_call/EXPECTED.md
@@ -0,0 +1,4 @@
+# 期望：编译错误
+
+- `A` ↔ `B` 函数体循环调用（无界递归）
+- 报错类别：有界 CALL 检查拒绝循环调用
diff --git a/tests/cases/19_recursive_call/main.st b/tests/cases/19_recursive_call/main.st
new file mode 100644
index 0000000..8cf5455
--- /dev/null
+++ b/tests/cases/19_recursive_call/main.st
@@ -0,0 +1,14 @@
+FUNCTION A : INT
+    A := B();
+END_FUNCTION
+
+FUNCTION B : INT
+    B := A();
+END_FUNCTION
+
+PROGRAM MAIN
+VAR
+    x : INT;
+END_VAR
+    x := A();
+END_PROGRAM
diff --git a/tests/cases/19_recursive_call/project.toml b/tests/cases/19_recursive_call/project.toml
new file mode 100644
index 0000000..36e8e6c
--- /dev/null
+++ b/tests/cases/19_recursive_call/project.toml
@@ -0,0 +1,8 @@
+[project]
+name = "case19"
+entry = "program MAIN"
+cycle_limit = 1000
+dt_ms = 10
+
+[files]
+st = ["main.st"]
diff --git a/tests/cases/20_line1/EXPECTED.md b/tests/cases/20_line1/EXPECTED.md
new file mode 100644
index 0000000..dee5181
--- /dev/null
+++ b/tests/cases/20_line1/EXPECTED.md
@@ -0,0 +1,11 @@
+# 期望：编译通过；I 组合 → `Q0_0` 与急停语义一致
+
+| I0_0 | I0_1 | EmergencyStop | Q0_0 |
+|---|---|---|---|
+| TRUE | FALSE | FALSE | TRUE |
+| TRUE | TRUE | FALSE | FALSE |
+| FALSE | FALSE | FALSE | FALSE |
+| TRUE | FALSE | TRUE | FALSE |
+
+- `Q0_0 = I0_0 AND NOT I0_1 AND NOT EmergencyStop`
+- 固定 I 序列跑两遍，槽位与工程哈希一致（回放确定性）
diff --git a/tests/cases/20_line1/globals.st b/tests/cases/20_line1/globals.st
new file mode 100644
index 0000000..6baeaa6
--- /dev/null
+++ b/tests/cases/20_line1/globals.st
@@ -0,0 +1,7 @@
+(* globals.st *)
+VAR_GLOBAL
+    EmergencyStop : BOOL := FALSE;
+    I0_0 : BOOL;
+    I0_1 : BOOL;
+    Q0_0 : BOOL;
+END_VAR
diff --git a/tests/cases/20_line1/main.st b/tests/cases/20_line1/main.st
new file mode 100644
index 0000000..fef1b92
--- /dev/null
+++ b/tests/cases/20_line1/main.st
@@ -0,0 +1,8 @@
+(* main.st *)
+PROGRAM MAIN
+VAR
+    starter : MotorStarter;
+END_VAR
+    starter(start := I0_0, stop := I0_1);
+    Q0_0 := starter.Q;
+END_PROGRAM
diff --git a/tests/cases/20_line1/motor.st b/tests/cases/20_line1/motor.st
new file mode 100644
index 0000000..69de7df
--- /dev/null
+++ b/tests/cases/20_line1/motor.st
@@ -0,0 +1,13 @@
+(* motor.st *)
+FUNCTION_BLOCK MotorStarter
+VAR_EXTERNAL
+    EmergencyStop : BOOL;
+END_VAR
+VAR_INPUT
+    start, stop : BOOL;
+END_VAR
+VAR_OUTPUT
+    Q : BOOL;
+END_VAR
+    Q := start AND NOT stop AND NOT EmergencyStop;
+END_FUNCTION_BLOCK
diff --git a/tests/cases/20_line1/project.toml b/tests/cases/20_line1/project.toml
new file mode 100644
index 0000000..3f6658f
--- /dev/null
+++ b/tests/cases/20_line1/project.toml
@@ -0,0 +1,28 @@
+[project]
+name = "line1"
+entry = "program MAIN"
+cycle_limit = 100000
+dt_ms = 10
+
+[files]
+st = ["globals.st", "motor.st", "main.st"]
+
+# 全工程只允许这一处出现 VAR_GLOBAL（第一版：单个文件）
+[gvl]
+file = "globals.st"
+
+# 可选：I/O 绑定。不创造变量，var 必须已在 GVL 里声明
+[[io.input]]
+var = "EmergencyStop"
+channel = 0
+bit = 2
+
+[[io.input]]
+var = "I0_0"
+channel = 0
+bit = 0
+
+[[io.output]]
+var = "Q0_0"
+channel = 0
+bit = 0