Prevent mixing deprecated check-cfg syntax with new one

compiler/rustc_interface/src/interface.rs

@@ -147,6 +147,12 @@ pub fn parse_check_cfg(handler: &EarlyErrorHandler, specs: Vec<String>) -> Check
                 };
             }
 
+            let cannot_mix_error = || {
+                error!(
+                    "cannot mix `cfg(...)` with deprecated syntax `names(...)` and `values(...)`"
+                )
+            };
+
             let expected_error = || -> ! {
                 error!("expected `cfg(name, values(\"value1\", \"value2\", ... \"valueN\"))`")
             };
@@ -174,6 +180,8 @@ pub fn parse_check_cfg(handler: &EarlyErrorHandler, specs: Vec<String>) -> Check
                 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);
 
@@ -194,6 +202,8 @@ pub fn parse_check_cfg(handler: &EarlyErrorHandler, specs: Vec<String>) -> Check
                 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);
 
@@ -237,6 +247,9 @@ pub fn parse_check_cfg(handler: &EarlyErrorHandler, specs: Vec<String>) -> Check
                     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();

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"));
    |                                                    ^^^^^^^^^^^^^^^^^