[gcc r16-5861] gccrs: Add missing test for lang item feature gate

[Arthur Cohen]

https://gcc.gnu.org/g:274ac329f2dfc84cda8350461370eaca4033f712

commit r16-5861-g274ac329f2dfc84cda8350461370eaca4033f712
Author: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>
Date:   Sat Nov 29 01:56:52 2025 +0100

    gccrs: Add missing test for lang item feature gate
    
    We recently modified all tests with lang items to add the lang feature
    gate switch but we did not introduce any test to check that a proper
    error message is printed when this switch is not used.
    
    gcc/testsuite/ChangeLog:
    
            * rust/compile/lang_feature_gate.rs: New test.
    
    Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

Diff:
---
 gcc/testsuite/rust/compile/lang_feature_gate.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/gcc/testsuite/rust/compile/lang_feature_gate.rs b/gcc/testsuite/rust/compile/lang_feature_gate.rs
new file mode 100644
index 000000000000..4cd485ec6ea9
--- /dev/null
+++ b/gcc/testsuite/rust/compile/lang_feature_gate.rs
@@ -0,0 +1,2 @@
+#[lang = "sized"] // { dg-error "lang items are subject to change. add .#!.feature.lang_items... to the crate attributes to enable" }
+pub trait Sized {}