Document //@ needs-target-std in rustc-dev-guide

jieyouxu · jieyouxu · commit c5b81235742c · 2025-06-10T22:17:57.000+08:00
diff --git a/src/doc/rustc-dev-guide/src/tests/directives.md b/src/doc/rustc-dev-guide/src/tests/directives.md
@@ -202,6 +202,7 @@ settings:
   `//@ needs-crate-type: cdylib, proc-macro` will cause the test to be ignored
   on `wasm32-unknown-unknown` target because the target does not support the
   `proc-macro` crate type.
+- `needs-target-std` — ignores if target platform does not have std support.
 
 The following directives will check LLVM support:
 
