pcx.is_non_exhaustive no longer used

Author: Nadrieril

compiler/rustc_mir_build/src/thir/pattern/usefulness.rs

@@ -368,8 +368,6 @@ pub(super) struct PatCtxt<'a, 'p, 'tcx> {
     /// Whether the current pattern is the whole pattern as found in a match arm, or if it's a
     /// subpattern.
     pub(super) is_top_level: bool,
-    /// Whether the current pattern is from a `non_exhaustive` enum.
-    pub(super) is_non_exhaustive: bool,
 }
 
 impl<'a, 'p, 'tcx> fmt::Debug for PatCtxt<'a, 'p, 'tcx> {
@@ -826,9 +824,8 @@ fn is_useful<'p, 'tcx>(
                 ty = row.head().ty();
             }
         }
-        let is_non_exhaustive = cx.is_foreign_non_exhaustive_enum(ty);
         debug!("v.head: {:?}, v.span: {:?}", v.head(), v.head().span());
-        let pcx = &PatCtxt { cx, ty, span: v.head().span(), is_top_level, is_non_exhaustive };
+        let pcx = &PatCtxt { cx, ty, span: v.head().span(), is_top_level };
 
         let v_ctor = v.head().ctor();
         debug!(?v_ctor);
@@ -843,7 +840,8 @@ fn is_useful<'p, 'tcx>(
         }
         // We split the head constructor of `v`.
         let split_ctors = v_ctor.split(pcx, matrix.heads().map(DeconstructedPat::ctor));
-        let is_non_exhaustive_and_wild = is_non_exhaustive && v_ctor.is_wildcard();
+        let is_non_exhaustive_and_wild =
+            cx.is_foreign_non_exhaustive_enum(ty) && v_ctor.is_wildcard();
         // For each constructor, we compute whether there's a value that starts with it that would
         // witness the usefulness of `v`.
         let start_matrix = &matrix;