rustc: Fix cfg(not(a, b)) to be not(a && b)

Previously, the cfg attribute `cfg(not(a, b))` was translated to `(!a && !b)`,
but this isn't very useful because that can already be expressed as
`cfg(not(a), not(b))`. This commit changes the translation to `!(a && b)` which
is more symmetrical of the rest of the `cfg` attribute.

Put another way, I would expect `cfg(clause)` to be the opposite of
`cfg(not(clause))`, but this is not currently the case with multiple element
clauses.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/libsyntax/attr.rs b/src/libsyntax/attr.rs
index ed56ef15a1c..7ff9a73f29d 100644
--- a/src/libsyntax/attr.rs
+++ b/src/libsyntax/attr.rs
@@ -317,9 +317,9 @@ pub fn test_cfg<AM: AttrMetaMethods, It: Iterator<AM>>
                                 debug!("not!");
                                 // inside #[cfg(not(...))], so these need to all
                                 // not match.
-                                not_cfgs.iter().all(|mi| {
+                                !not_cfgs.iter().all(|mi| {
                                     debug!("cfg(not({}[...]))", mi.name());
-                                    !contains(cfg, *mi)
+                                    contains(cfg, *mi)
                                 })
                             }
                             _ => contains(cfg, *cfg_mi)