From 50e61a1a667929d0db91132246e61c1a67ab07af Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lo=C3=AFc=20BRANSTETT?= <lolo.branstett@numericable.fr>
Date: Fri, 25 Feb 2022 13:43:57 +0100
Subject: [PATCH] Add support for values() with --check-cfg

---
 compiler/rustc_interface/src/interface.rs | 3 +++
 compiler/rustc_session/src/config.rs      | 9 ++++++++-
 src/test/ui/check-cfg/empty-values.rs     | 4 ++--
 src/test/ui/check-cfg/empty-values.stderr | 2 --
 4 files changed, 13 insertions(+), 5 deletions(-)
 delete mode 100644 src/test/ui/check-cfg/empty-values.stderr

diff --git a/compiler/rustc_interface/src/interface.rs b/compiler/rustc_interface/src/interface.rs
index 7f4a4ffadec..e7563933c88 100644
--- a/compiler/rustc_interface/src/interface.rs
+++ b/compiler/rustc_interface/src/interface.rs
@@ -207,6 +207,9 @@ pub fn parse_check_cfg(specs: Vec<String>) -> CheckCfg {
                                             "`values()` first argument must be a simple identifer"
                                         );
                                     }
+                                } else if args.is_empty() {
+                                    cfg.well_known_values = true;
+                                    continue 'specs;
                                 }
                             }
                         }
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index f9b75690e37..02cfdcf86f8 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -1025,13 +1025,19 @@ pub fn to_crate_config(cfg: FxHashSet<(String, Option<String>)>) -> CrateConfig
 pub struct CheckCfg<T = String> {
     /// The set of all `names()`, if None no name checking is performed
     pub names_valid: Option<FxHashSet<T>>,
+    /// Is well known values activated
+    pub well_known_values: bool,
     /// The set of all `values()`
     pub values_valid: FxHashMap<T, FxHashSet<T>>,
 }
 
 impl<T> Default for CheckCfg<T> {
     fn default() -> Self {
-        CheckCfg { names_valid: Default::default(), values_valid: Default::default() }
+        CheckCfg {
+            names_valid: Default::default(),
+            values_valid: Default::default(),
+            well_known_values: false,
+        }
     }
 }
 
@@ -1047,6 +1053,7 @@ impl<T> CheckCfg<T> {
                 .iter()
                 .map(|(a, b)| (f(a), b.iter().map(|b| f(b)).collect()))
                 .collect(),
+            well_known_values: self.well_known_values,
         }
     }
 }
diff --git a/src/test/ui/check-cfg/empty-values.rs b/src/test/ui/check-cfg/empty-values.rs
index 38ef9e51c7a..5464846409a 100644
--- a/src/test/ui/check-cfg/empty-values.rs
+++ b/src/test/ui/check-cfg/empty-values.rs
@@ -1,6 +1,6 @@
-// Check that a an empty values() is rejected
+// Check that a an empty values() pass
 //
-// check-fail
+// check-pass
 // compile-flags: --check-cfg=values() -Z unstable-options
 
 fn main() {}
diff --git a/src/test/ui/check-cfg/empty-values.stderr b/src/test/ui/check-cfg/empty-values.stderr
deleted file mode 100644
index 106d5b7b47f..00000000000
--- a/src/test/ui/check-cfg/empty-values.stderr
+++ /dev/null
@@ -1,2 +0,0 @@
-error: invalid `--check-cfg` argument: `values()` (expected `names(name1, name2, ... nameN)` or `values(name, "value1", "value2", ... "valueN")`)
-