compiletest: add enable-by-default check-cfg

Author: Urgau

src/tools/compiletest/src/runtest.rs

@@ -1028,12 +1028,31 @@ impl<'test> TestCx<'test> {
     }
 
     fn set_revision_flags(&self, cmd: &mut Command) {
+        // Normalize revisions to be lowercase and replace `-`s with `_`s.
+        // Otherwise the `--cfg` flag is not valid.
+        let normalize_revision = |revision: &str| revision.to_lowercase().replace("-", "_");
+
         if let Some(revision) = self.revision {
-            // Normalize revisions to be lowercase and replace `-`s with `_`s.
-            // Otherwise the `--cfg` flag is not valid.
-            let normalized_revision = revision.to_lowercase().replace("-", "_");
+            let normalized_revision = normalize_revision(revision);
             cmd.args(&["--cfg", &normalized_revision]);
         }
+
+        if !self.props.no_auto_check_cfg {
+            let mut check_cfg = String::with_capacity(25);
+
+            // Generate `cfg(FALSE, REV1, ..., REVN)` (for all possible revisions)
+            //
+            // For compatibility reason we consider the `FALSE` cfg to be expected
+            // since it is extensively used in the testsuite.
+            check_cfg.push_str("cfg(FALSE");
+            for revision in &self.props.revisions {
+                check_cfg.push_str(",");
+                check_cfg.push_str(&normalize_revision(&revision));
+            }
+            check_cfg.push_str(")");
+
+            cmd.args(&["--check-cfg", &check_cfg]);
+        }
     }
 
     fn typecheck_source(&self, src: String) -> ProcRes {

tests/rustdoc-ui/argfile/commandline-argfile.rs

@@ -1,13 +1,13 @@
 // Check to see if we can get parameters from an @argsfile file
 //
 //@ check-pass
-//@ compile-flags: --cfg cmdline_set @{{src-base}}/argfile/commandline-argfile.args
+//@ compile-flags: --cfg cmdline_set --check-cfg=cfg(cmdline_set,unbroken)
+//@ compile-flags: @{{src-base}}/argfile/commandline-argfile.args
 
 #[cfg(not(cmdline_set))]
 compile_error!("cmdline_set not set");
 
 #[cfg(not(unbroken))]
 compile_error!("unbroken not set");
 
-fn main() {
-}
+fn main() {}

tests/ui/argfile/commandline-argfile.rs

@@ -1,13 +1,13 @@
 // Check to see if we can get parameters from an @argsfile file
 //
 //@ build-pass
-//@ compile-flags: --cfg cmdline_set @{{src-base}}/argfile/commandline-argfile.args
+//@ compile-flags: --cfg cmdline_set --check-cfg=cfg(cmdline_set,unbroken)
+//@ compile-flags: @{{src-base}}/argfile/commandline-argfile.args
 
 #[cfg(not(cmdline_set))]
 compile_error!("cmdline_set not set");
 
 #[cfg(not(unbroken))]
 compile_error!("unbroken not set");
 
-fn main() {
-}
+fn main() {}

tests/ui/cfg/cfg-in-crate-1.rs

@@ -1,5 +1,6 @@
 //@ run-pass
-//@ compile-flags: --cfg bar -D warnings
+//@ compile-flags: --cfg bar --check-cfg=cfg(bar) -D warnings
+
 #![cfg(bar)]
 
 fn main() {}

tests/ui/cfg/cfg-macros-foo.rs

@@ -1,5 +1,5 @@
 //@ run-pass
-//@ compile-flags: --cfg foo
+//@ compile-flags: --cfg foo --check-cfg=cfg(foo)
 
 // check that cfg correctly chooses between the macro impls (see also
 // cfg-macros-notfoo.rs)

tests/ui/cfg/cfg-path-error.rs

@@ -1,5 +1,7 @@
 //@ check-fail
 
+#![allow(unexpected_cfgs)] // invalid cfgs
+
 #[cfg(any(foo, foo::bar))]
 //~^ERROR `cfg` predicate key must be an identifier
 fn foo1() {}

tests/ui/cfg/cfg-path-error.stderr

@@ -1,23 +1,23 @@
 error: `cfg` predicate key must be an identifier
-  --> $DIR/cfg-path-error.rs:3:16
+  --> $DIR/cfg-path-error.rs:5:16
    |
 LL | #[cfg(any(foo, foo::bar))]
    |                ^^^^^^^^
 
 error: `cfg` predicate key must be an identifier
-  --> $DIR/cfg-path-error.rs:7:11
+  --> $DIR/cfg-path-error.rs:9:11
    |
 LL | #[cfg(any(foo::bar, foo))]
    |           ^^^^^^^^
 
 error: `cfg` predicate key must be an identifier
-  --> $DIR/cfg-path-error.rs:11:16
+  --> $DIR/cfg-path-error.rs:13:16
    |
 LL | #[cfg(all(foo, foo::bar))]
    |                ^^^^^^^^
 
 error: `cfg` predicate key must be an identifier
-  --> $DIR/cfg-path-error.rs:15:11
+  --> $DIR/cfg-path-error.rs:17:11
    |
 LL | #[cfg(all(foo::bar, foo))]
    |           ^^^^^^^^

tests/ui/cfg/cfg_attr.rs

@@ -1,6 +1,8 @@
 //@ run-pass
 //@ compile-flags:--cfg set1 --cfg set2
-#![allow(dead_code)]
+
+#![allow(dead_code, unexpected_cfgs)]
+
 use std::fmt::Debug;
 
 struct NotDebugable;

tests/ui/cfg/cfgs-on-items.rs

@@ -1,8 +1,7 @@
 //@ run-pass
-//@ compile-flags: --cfg fooA --cfg fooB
+//@ compile-flags: --cfg fooA --cfg fooB --check-cfg=cfg(fooA,fooB,fooC,bar)
 
 // fooA AND !bar
-
 #[cfg(all(fooA, not(bar)))]
 fn foo1() -> isize { 1 }
 

tests/ui/cfg/diagnostics-not-a-def.rs

@@ -1,4 +1,7 @@
+#![feature(lint_reasons)]
+
 pub mod inner {
+    #[expect(unexpected_cfgs)]
     pub fn i_am_here() {
         #[cfg(feature = "another one that doesn't exist")]
         loop {}