From 5f0043ace66f0db0581bc4bc52d90773cc23d3ac Mon Sep 17 00:00:00 2001
From: Urgau <urgau@numericable.fr>
Date: Fri, 31 May 2024 15:39:10 +0200
Subject: [PATCH 1/2] Handle no values cfg with --print=check-cfg

---
 compiler/rustc_driver_impl/src/lib.rs          | 18 +++++++++++-------
 .../src/compiler-flags/print-check-cfg.md      |  1 +
 tests/run-make/print-check-cfg/rmake.rs        | 14 ++++++++++++++
 3 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/compiler/rustc_driver_impl/src/lib.rs b/compiler/rustc_driver_impl/src/lib.rs
index 08b97b4953e97..627fd74c8d77c 100644
--- a/compiler/rustc_driver_impl/src/lib.rs
+++ b/compiler/rustc_driver_impl/src/lib.rs
@@ -814,13 +814,17 @@ fn print_crate_info(
                     match expected_values {
                         ExpectedValues::Any => check_cfgs.push(format!("{name}=any()")),
                         ExpectedValues::Some(values) => {
-                            check_cfgs.extend(values.iter().map(|value| {
-                                if let Some(value) = value {
-                                    format!("{name}=\"{value}\"")
-                                } else {
-                                    name.to_string()
-                                }
-                            }))
+                            if !values.is_empty() {
+                                check_cfgs.extend(values.iter().map(|value| {
+                                    if let Some(value) = value {
+                                        format!("{name}=\"{value}\"")
+                                    } else {
+                                        name.to_string()
+                                    }
+                                }))
+                            } else {
+                                check_cfgs.push(format!("{name}="))
+                            }
                         }
                     }
                 }
diff --git a/src/doc/unstable-book/src/compiler-flags/print-check-cfg.md b/src/doc/unstable-book/src/compiler-flags/print-check-cfg.md
index e55165b537404..a9237a0f4ef75 100644
--- a/src/doc/unstable-book/src/compiler-flags/print-check-cfg.md
+++ b/src/doc/unstable-book/src/compiler-flags/print-check-cfg.md
@@ -15,6 +15,7 @@ This print option works similarly to `--print=cfg` (modulo check-cfg specifics):
  - `cfg(feature, values("foo", "bar"))`: `feature="foo"` and `feature="bar"`
  - `cfg(feature, values(none(), ""))`: `feature` and `feature=""`
  - `cfg(feature, values(any()))`: `feature=any()`
+ - `cfg(feature, values())`: `feature=`
  - `cfg(any())`: `any()`
  - *nothing*: `any()=any()`
 
diff --git a/tests/run-make/print-check-cfg/rmake.rs b/tests/run-make/print-check-cfg/rmake.rs
index 2d52216442653..a0aa95c8abcf6 100644
--- a/tests/run-make/print-check-cfg/rmake.rs
+++ b/tests/run-make/print-check-cfg/rmake.rs
@@ -48,6 +48,20 @@ fn main() {
             doesnt_contain: &["any()", "any()=any()", "feature=none()", "feature="],
         },
     });
+    check(CheckCfg {
+        args: &["--check-cfg=cfg(feature, values())"],
+        contains: Contains::Some {
+            contains: &["feature="],
+            doesnt_contain: &["any()", "any()=any()", "feature=none()", "feature"],
+        },
+    });
+    check(CheckCfg {
+        args: &["--check-cfg=cfg(feature, values())", "--check-cfg=cfg(feature, values(none()))"],
+        contains: Contains::Some {
+            contains: &["feature"],
+            doesnt_contain: &["any()", "any()=any()", "feature=none()", "feature="],
+        },
+    });
     check(CheckCfg {
         args: &[
             r#"--check-cfg=cfg(feature, values(any()))"#,

From f58bf91aceb7bc029bd130a84cbb156f9149491d Mon Sep 17 00:00:00 2001
From: Urgau <urgau@numericable.fr>
Date: Fri, 31 May 2024 15:42:07 +0200
Subject: [PATCH 2/2] Add missing tracking issue number for --print=check-cfg

---
 src/doc/unstable-book/src/compiler-flags/print-check-cfg.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/doc/unstable-book/src/compiler-flags/print-check-cfg.md b/src/doc/unstable-book/src/compiler-flags/print-check-cfg.md
index a9237a0f4ef75..ab63c986e856e 100644
--- a/src/doc/unstable-book/src/compiler-flags/print-check-cfg.md
+++ b/src/doc/unstable-book/src/compiler-flags/print-check-cfg.md
@@ -1,6 +1,6 @@
 # `print=check-cfg`
 
-The tracking issue for this feature is: [#XXXXXX](https://github.com/rust-lang/rust/issues/XXXXXX).
+The tracking issue for this feature is: [#125704](https://github.com/rust-lang/rust/issues/125704).
 
 ------------------------