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authorSantiago Pastorino <spastorino@gmail.com>2021-10-22 09:34:36 -0300
committerSantiago Pastorino <spastorino@gmail.com>2021-10-22 09:34:36 -0300
commitc4c76a4fbd046066eb5490d7e5aec4c263e12fde (patch)
treef29c4917066fffc4ec5bd6988e45f4050cefcd80 /compiler/rustc_infer
parent7829d9dde3798f16b3db5841593ba1242930a587 (diff)
downloadrust-c4c76a4fbd046066eb5490d7e5aec4c263e12fde.tar.gz
rust-c4c76a4fbd046066eb5490d7e5aec4c263e12fde.zip
Document flip polarity
Diffstat (limited to 'compiler/rustc_infer')
-rw-r--r--compiler/rustc_infer/src/traits/mod.rs3
1 files changed, 3 insertions, 0 deletions
diff --git a/compiler/rustc_infer/src/traits/mod.rs b/compiler/rustc_infer/src/traits/mod.rs
index 033d634cdb7..e8622b3c819 100644
--- a/compiler/rustc_infer/src/traits/mod.rs
+++ b/compiler/rustc_infer/src/traits/mod.rs
@@ -56,6 +56,9 @@ pub type PredicateObligation<'tcx> = Obligation<'tcx, ty::Predicate<'tcx>>;
 pub type TraitObligation<'tcx> = Obligation<'tcx, ty::PolyTraitPredicate<'tcx>>;
 
 impl PredicateObligation<'tcx> {
+    /// Flips the polarity of the inner predicate.
+    ///
+    /// Given `T: Trait` predicate it returns `T: !Trait` and given `T: !Trait` returns `T: Trait`.
     pub fn flip_polarity(&self, tcx: TyCtxt<'tcx>) -> Option<PredicateObligation<'tcx>> {
         Some(PredicateObligation {
             cause: self.cause.clone(),