Merge pull request #71908 from jckarter/borrow-all-accessor-bases

SILGen: Borrow any move-only or borrow-expr'ed accessor base.

Author: jckarter

lib/SILGen/SILGenLValue.cpp

@@ -3734,12 +3734,6 @@ static bool shouldEmitSelfAsRValue(AccessorDecl *fn, CanType selfType,
     return false;
   case SelfAccessKind::Borrowing:
   case SelfAccessKind::NonMutating:
-    // If the accessor is a coroutine, we may want to access the projected
-    // value through a borrow of the base. But if it's a regular get/set then
-    // there isn't any real benefit to doing so.
-    if (!fn->isCoroutine()) {
-      return true;
-    }
     // Normally we'll copy the base to minimize accesses. But if the base
     // is noncopyable, or we're accessing it in a `borrow` expression, then
     // we want to keep the access nested on the original base.

test/SILOptimizer/moveonly_borrowing_switch.swift

@@ -342,3 +342,10 @@ extension ChonkyList {
         }
     }
 }
+
+// https://github.com/apple/swift/issues/71598
+struct RangeHolder:~Copyable
+{
+    var r:Range<Int> { fatalError() }
+    var y:Int { self.r.upperBound }
+}