pattern typing cleanup: remove a redundant assignment

As far as I can tell, the assignment removed here will never do
anything. `pat_info.max_ref_mutbl` starts at `MutblCap::Mut` for the
top-level pattern and is only changed if feature gates are enabled that
would result in the statement not being executed. Regardless of what new
pattern typing rules are adopted, I don't imagine we want to
conditionally reset `max_ref_mutbl` based on edition either, since it'd
have consequences for subpatterns in other editions.

1 files changed, 3 insertions, 7 deletions

diff --git a/compiler/rustc_hir_typeck/src/pat.rs b/compiler/rustc_hir_typeck/src/pat.rs
index 4870e6193c3..5e6cca51c92 100644
--- a/compiler/rustc_hir_typeck/src/pat.rs
+++ b/compiler/rustc_hir_typeck/src/pat.rs
@@ -2216,13 +2216,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let pat_prefix_span =
             inner.span.find_ancestor_inside(pat.span).map(|end| pat.span.until(end));
 
-        if no_ref_mut_behind_and {
-            if pat_mutbl == Mutability::Not {
-                // Prevent the inner pattern from binding with `ref mut`.
-                pat_info.max_ref_mutbl = pat_info.max_ref_mutbl.cap_to_weakly_not(pat_prefix_span);
-            }
-        } else {
-            pat_info.max_ref_mutbl = MutblCap::Mut;
+        if no_ref_mut_behind_and && pat_mutbl == Mutability::Not {
+            // Prevent the inner pattern from binding with `ref mut`.
+            pat_info.max_ref_mutbl = pat_info.max_ref_mutbl.cap_to_weakly_not(pat_prefix_span);
         }
 
         expected = self.try_structurally_resolve_type(pat.span, expected);