From fd7b6744e83c76e543cc2fd985ef655dd9183874 Mon Sep 17 00:00:00 2001
From: Urgau <urgau@numericable.fr>
Date: Fri, 27 Oct 2023 16:27:37 +0200
Subject: [PATCH 1/2] Remove outdated option to -Zcheck-cfg warnings

---
 src/cargo/core/compiler/custom_build.rs | 2 +-
 src/cargo/util/config/target.rs         | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/cargo/core/compiler/custom_build.rs b/src/cargo/core/compiler/custom_build.rs
index b3412e1d073..022ad87613a 100644
--- a/src/cargo/core/compiler/custom_build.rs
+++ b/src/cargo/core/compiler/custom_build.rs
@@ -803,7 +803,7 @@ impl BuildOutput {
                     if extra_check_cfg {
                         check_cfgs.push(value.to_string());
                     } else {
-                        warnings.push(format!("cargo:{} requires -Zcheck-cfg=output flag", key));
+                        warnings.push(format!("cargo:{} requires -Zcheck-cfg flag", key));
                     }
                 }
                 "rustc-env" => {
diff --git a/src/cargo/util/config/target.rs b/src/cargo/util/config/target.rs
index de00b5b115a..0e2029ffc56 100644
--- a/src/cargo/util/config/target.rs
+++ b/src/cargo/util/config/target.rs
@@ -208,7 +208,7 @@ fn parse_links_overrides(
                         output.check_cfgs.extend(list.iter().map(|v| v.0.clone()));
                     } else {
                         config.shell().warn(format!(
-                            "target config `{}.{}` requires -Zcheck-cfg=output flag",
+                            "target config `{}.{}` requires -Zcheck-cfg flag",
                             target_key, key
                         ))?;
                     }

From e396904b25713f80e40f47e022f18ef4c50efde1 Mon Sep 17 00:00:00 2001
From: Urgau <urgau@numericable.fr>
Date: Fri, 27 Oct 2023 17:10:49 +0200
Subject: [PATCH 2/2] Add feature gate test for check-cfg config, build script
 and override

---
 tests/testsuite/check_cfg.rs | 92 ++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)

diff --git a/tests/testsuite/check_cfg.rs b/tests/testsuite/check_cfg.rs
index dbc67582524..30c3d0459c2 100644
--- a/tests/testsuite/check_cfg.rs
+++ b/tests/testsuite/check_cfg.rs
@@ -354,6 +354,41 @@ fn build_script_override() {
         .run();
 }
 
+#[cargo_test]
+fn build_script_override_feature_gate() {
+    let target = cargo_test_support::rustc_host();
+
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.1.0"
+                links = "a"
+            "#,
+        )
+        .file("src/main.rs", "fn main() {}")
+        .file("build.rs", "fn main() {}")
+        .file(
+            ".cargo/config",
+            &format!(
+                r#"
+                    [target.{}.a]
+                    rustc-check-cfg = ["cfg(foo)"]
+                "#,
+                target
+            ),
+        )
+        .build();
+
+    p.cargo("check")
+        .with_stderr_contains(
+            "warning: target config[..]rustc-check-cfg[..] requires -Zcheck-cfg flag",
+        )
+        .run();
+}
+
 #[cargo_test(nightly, reason = "--check-cfg is unstable")]
 fn build_script_test() {
     let p = project()
@@ -409,6 +444,34 @@ fn build_script_test() {
         .run();
 }
 
+#[cargo_test]
+fn build_script_feature_gate() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.0.1"
+                build = "build.rs"
+            "#,
+        )
+        .file(
+            "build.rs",
+            r#"fn main() { 
+                println!("cargo:rustc-check-cfg=cfg(foo)");
+                println!("cargo:rustc-cfg=foo");
+            }"#,
+        )
+        .file("src/main.rs", "fn main() {}")
+        .build();
+
+    p.cargo("check")
+        .with_stderr_contains("warning[..]cargo:rustc-check-cfg requires -Zcheck-cfg flag")
+        .with_status(0)
+        .run();
+}
+
 #[cargo_test(nightly, reason = "--check-cfg is unstable")]
 fn config_valid() {
     let p = project()
@@ -467,3 +530,32 @@ fn config_invalid() {
         .with_status(101)
         .run();
 }
+
+#[cargo_test]
+fn config_feature_gate() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.1.0"
+
+                [features]
+                f_a = []
+            "#,
+        )
+        .file("src/main.rs", "fn main() {}")
+        .file(
+            ".cargo/config.toml",
+            r#"
+                [unstable]
+                check-cfg = true
+            "#,
+        )
+        .build();
+
+    p.cargo("check -v")
+        .with_stderr_does_not_contain("--check-cfg")
+        .run();
+}