_selftest/test_error.java · 2768 字节 · 下载原文

// test_error.java —— VML 诊断自测用例（**故意含错，不参与编译通过性检查**）

// test_error.java -- VML diagnostic self-test case (**deliberately contains errors, not part of the compile-cleanliness check**)

//

// 用途：验证编译器的错误/警告输出、诊断列表、以及编辑器能否显示气泡。

// Purpose: verify the compiler's error/warning output, the diagnostic list, and whether the editor can show a squiggle.

// 预期：1 个错误、**0 个警告**（详见下）。

// Expected: 1 error, **0 warnings** (see below).

// 约束：确定性 —— 无随机数、不读文件、不交互、无死循环；错误来自源码本身。

// Constraints: deterministic -- no randomness, no file reads, no interaction, no infinite loops; the error comes from the source itself.

//

// ⚠ `unused` 是刻意留的「未使用变量」探针。java 前端不报未使用变量

// ⚠ `unused` is a deliberately kept "unused variable" probe. The java frontend does not report unused variables

//   （该检测只在 CCompiler 里实现），因此本文件只产 1 条错误。

//   (that detection is implemented only in CCompiler), so this file produces only 1 error.

//   java 前端确实有「MCU 模式: synchronized/volatile 被忽略」两条警告，但走的是

//   The java frontend does have the two "MCU mode: synchronized/volatile ignored" warnings, but they go through

//   VMLPlugins.WarningEmitter，被 WarningLevel 门控、默认 0 ⇒ vmlcli 与手机端

//   VMLPlugins.WarningEmitter, gated by WarningLevel and defaulting to 0 => vmlcli and the mobile client

//   都不开启（且该通道不带 文件:行:列 与诊断码，编辑器无法定位）。

//   never enable it (and that channel carries no file:line:col or diag-code, so the editor cannot locate anything).

// ⚠ 本条错误的文件名显示为 `<input>` 而不是真实路径。

// ⚠ This file's error shows the filename as `<input>` rather than the real path.

// ✅ 2026-10-04 复验仍成立：产出 1 error（`CodeGen_UndefinedVariable`，文件名显示为 `<input>`）、0 warning；

// ✅ Re-verified 2026-10-04, still holds: yields 1 error (`CodeGen_UndefinedVariable`, filename shown as `<input>`), 0 warnings;

//    java 的「MCU 模式: synchronized/volatile 被忽略」两条警告仍在源码里（`JavaCompiler/Parser.cs:294/298`），默认不开启。

//    the two "MCU mode: synchronized/volatile ignored" warnings are still in the source (`JavaCompiler/Parser.cs:294/298`), off by default.

public class P {
  public static void main(String[] a) {
    int unused = 5;
    System.out.println("java diag probe");
    int x = undefinedValue;
    System.out.println(x);
  }
}