Prevent mixing deprecated check-cfg syntax with new one

Cargo.lock

@@ -2215,9 +2215,9 @@ checksum = "db13adb97ab515a3691f56e4dbab09283d0b86cb45abd991d8634a9d6f501760"
 
 [[package]]
 name = "libc"
-version = "0.2.149"
+version = "0.2.150"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a08173bc88b7955d1b3145aa561539096c421ac8debde8cbc3612ec635fee29b"
+checksum = "89d92a4743f9a61002fae18374ed11e7973f530cb3a3255fb354818118b2203c"
 dependencies = [
  "rustc-std-workspace-core",
 ]

compiler/rustc_interface/src/interface.rs

@@ -146,6 +146,10 @@ pub(crate) fn parse_check_cfg(handler: &EarlyErrorHandler, specs: Vec<String>) -
             error!("expected `cfg(name, values(\"value1\", \"value2\", ... \"valueN\"))`")
         };
 
+        let cannot_mix_error = || {
+            error!("cannot mix `cfg(...)` with deprecated syntax `names(...)` and `values(...)`")
+        };
+
         let Ok(mut parser) = maybe_new_parser_from_source_str(&sess, filename, s.to_string())
         else {
             expected_error();
@@ -169,6 +173,8 @@ pub(crate) fn parse_check_cfg(handler: &EarlyErrorHandler, specs: Vec<String>) -
             if old_syntax == None {
                 check_cfg.exhaustive_names = false;
                 check_cfg.exhaustive_values = false;
+            } else if old_syntax == Some(false) {
+                cannot_mix_error();
             }
             old_syntax = Some(true);
         };
@@ -226,6 +232,9 @@ pub(crate) fn parse_check_cfg(handler: &EarlyErrorHandler, specs: Vec<String>) -
                 expected_error();
             }
         } else if meta_item.has_name(sym::cfg) {
+            if old_syntax == Some(true) {
+                cannot_mix_error();
+            }
             old_syntax = Some(false);
 
             let mut names = Vec::new();

library/std/Cargo.toml

@@ -17,7 +17,7 @@ cfg-if = { version = "1.0", features = ['rustc-dep-of-std'] }
 panic_unwind = { path = "../panic_unwind", optional = true }
 panic_abort = { path = "../panic_abort" }
 core = { path = "../core", public = true }
-libc = { version = "0.2.149", default-features = false, features = ['rustc-dep-of-std'], public = true }
+libc = { version = "0.2.150", default-features = false, features = ['rustc-dep-of-std'], public = true }
 compiler_builtins = { version = "0.1.103" }
 profiler_builtins = { path = "../profiler_builtins", optional = true }
 unwind = { path = "../unwind" }

src/bootstrap/src/core/builder.rs

@@ -1404,7 +1404,7 @@ impl<'a> Builder<'a> {
         }
 
         // #[cfg(bootstrap)]
-        let use_new_check_cfg_syntax = self.local_rebuild;
+        let use_new_check_cfg_syntax = stage >= 1;
 
         // Enable compile-time checking of `cfg` names, values and Cargo `features`.
         //

tests/ui/check-cfg/mix.cfg.stderr

@@ -1,37 +1,37 @@
 warning: unexpected `cfg` condition name: `widnows`
-  --> $DIR/mix.rs:15:7
+  --> $DIR/mix.rs:16:7
    |
 LL | #[cfg(widnows)]
    |       ^^^^^^^ help: there is a config with a similar name: `windows`
    |
    = note: `#[warn(unexpected_cfgs)]` on by default
 
 warning: unexpected `cfg` condition value: (none)
-  --> $DIR/mix.rs:19:7
+  --> $DIR/mix.rs:20:7
    |
 LL | #[cfg(feature)]
    |       ^^^^^^^- help: specify a config value: `= "foo"`
    |
    = note: expected values for `feature` are: `foo`
 
 warning: unexpected `cfg` condition value: `bar`
-  --> $DIR/mix.rs:26:7
+  --> $DIR/mix.rs:27:7
    |
 LL | #[cfg(feature = "bar")]
    |       ^^^^^^^^^^^^^^^
    |
    = note: expected values for `feature` are: `foo`
 
 warning: unexpected `cfg` condition value: `zebra`
-  --> $DIR/mix.rs:30:7
+  --> $DIR/mix.rs:31:7
    |
 LL | #[cfg(feature = "zebra")]
    |       ^^^^^^^^^^^^^^^^^
    |
    = note: expected values for `feature` are: `foo`
 
 warning: unexpected `cfg` condition name: `uu`
-  --> $DIR/mix.rs:34:12
+  --> $DIR/mix.rs:35:12
    |
 LL | #[cfg_attr(uu, test)]
    |            ^^
@@ -47,141 +47,141 @@ warning: unexpected `unknown_name` as condition name
    = help: was set with `--cfg` but isn't in the `--check-cfg` expected names
 
 warning: unexpected `cfg` condition name: `widnows`
-  --> $DIR/mix.rs:43:10
+  --> $DIR/mix.rs:44:10
    |
 LL |     cfg!(widnows);
    |          ^^^^^^^ help: there is a config with a similar name: `windows`
 
 warning: unexpected `cfg` condition value: `bar`
-  --> $DIR/mix.rs:46:10
+  --> $DIR/mix.rs:47:10
    |
 LL |     cfg!(feature = "bar");
    |          ^^^^^^^^^^^^^^^
    |
    = note: expected values for `feature` are: `foo`
 
 warning: unexpected `cfg` condition value: `zebra`
-  --> $DIR/mix.rs:48:10
+  --> $DIR/mix.rs:49:10
    |
 LL |     cfg!(feature = "zebra");
    |          ^^^^^^^^^^^^^^^^^
    |
    = note: expected values for `feature` are: `foo`
 
 warning: unexpected `cfg` condition name: `xxx`
-  --> $DIR/mix.rs:50:10
+  --> $DIR/mix.rs:51:10
    |
 LL |     cfg!(xxx = "foo");
    |          ^^^^^^^^^^^
 
 warning: unexpected `cfg` condition name: `xxx`
-  --> $DIR/mix.rs:52:10
+  --> $DIR/mix.rs:53:10
    |
 LL |     cfg!(xxx);
    |          ^^^
 
 warning: unexpected `cfg` condition name: `xxx`
-  --> $DIR/mix.rs:54:14
+  --> $DIR/mix.rs:55:14
    |
 LL |     cfg!(any(xxx, windows));
    |              ^^^
 
 warning: unexpected `cfg` condition value: `bad`
-  --> $DIR/mix.rs:56:14
+  --> $DIR/mix.rs:57:14
    |
 LL |     cfg!(any(feature = "bad", windows));
    |              ^^^^^^^^^^^^^^^
    |
    = note: expected values for `feature` are: `foo`
 
 warning: unexpected `cfg` condition name: `xxx`
-  --> $DIR/mix.rs:58:23
+  --> $DIR/mix.rs:59:23
    |
 LL |     cfg!(any(windows, xxx));
    |                       ^^^
 
 warning: unexpected `cfg` condition name: `xxx`
-  --> $DIR/mix.rs:60:20
+  --> $DIR/mix.rs:61:20
    |
 LL |     cfg!(all(unix, xxx));
    |                    ^^^
 
 warning: unexpected `cfg` condition name: `aa`
-  --> $DIR/mix.rs:62:14
+  --> $DIR/mix.rs:63:14
    |
 LL |     cfg!(all(aa, bb));
    |              ^^
 
 warning: unexpected `cfg` condition name: `bb`
-  --> $DIR/mix.rs:62:18
+  --> $DIR/mix.rs:63:18
    |
 LL |     cfg!(all(aa, bb));
    |                  ^^
 
 warning: unexpected `cfg` condition name: `aa`
-  --> $DIR/mix.rs:65:14
+  --> $DIR/mix.rs:66:14
    |
 LL |     cfg!(any(aa, bb));
    |              ^^
 
 warning: unexpected `cfg` condition name: `bb`
-  --> $DIR/mix.rs:65:18
+  --> $DIR/mix.rs:66:18
    |
 LL |     cfg!(any(aa, bb));
    |                  ^^
 
 warning: unexpected `cfg` condition value: `zebra`
-  --> $DIR/mix.rs:68:20
+  --> $DIR/mix.rs:69:20
    |
 LL |     cfg!(any(unix, feature = "zebra"));
    |                    ^^^^^^^^^^^^^^^^^
    |
    = note: expected values for `feature` are: `foo`
 
 warning: unexpected `cfg` condition name: `xxx`
-  --> $DIR/mix.rs:70:14
+  --> $DIR/mix.rs:71:14
    |
 LL |     cfg!(any(xxx, feature = "zebra"));
    |              ^^^
 
 warning: unexpected `cfg` condition value: `zebra`
-  --> $DIR/mix.rs:70:19
+  --> $DIR/mix.rs:71:19
    |
 LL |     cfg!(any(xxx, feature = "zebra"));
    |                   ^^^^^^^^^^^^^^^^^
    |
    = note: expected values for `feature` are: `foo`
 
 warning: unexpected `cfg` condition name: `xxx`
-  --> $DIR/mix.rs:73:14
+  --> $DIR/mix.rs:74:14
    |
 LL |     cfg!(any(xxx, unix, xxx));
    |              ^^^
 
 warning: unexpected `cfg` condition name: `xxx`
-  --> $DIR/mix.rs:73:25
+  --> $DIR/mix.rs:74:25
    |
 LL |     cfg!(any(xxx, unix, xxx));
    |                         ^^^
 
 warning: unexpected `cfg` condition value: `zebra`
-  --> $DIR/mix.rs:76:14
+  --> $DIR/mix.rs:77:14
    |
 LL |     cfg!(all(feature = "zebra", feature = "zebra", feature = "zebra"));
    |              ^^^^^^^^^^^^^^^^^
    |
    = note: expected values for `feature` are: `foo`
 
 warning: unexpected `cfg` condition value: `zebra`
-  --> $DIR/mix.rs:76:33
+  --> $DIR/mix.rs:77:33
    |
 LL |     cfg!(all(feature = "zebra", feature = "zebra", feature = "zebra"));
    |                                 ^^^^^^^^^^^^^^^^^
    |
    = note: expected values for `feature` are: `foo`
 
 warning: unexpected `cfg` condition value: `zebra`
-  --> $DIR/mix.rs:76:52
+  --> $DIR/mix.rs:77:52
    |
 LL |     cfg!(all(feature = "zebra", feature = "zebra", feature = "zebra"));
    |                                                    ^^^^^^^^^^^^^^^^^