SILGen: Produce move_values with a fresh cleanup.

If the value being moved was a trivial value of a nontrivial type (like nil
for Optional<T>) then the lifetime checker would complain that there was
no `destroy_value` ending the consumed value's lifetime. Partial fix
for #71608.

Author: jckarter

lib/SILGen/SILGenBuilder.cpp

@@ -1061,10 +1061,13 @@ ManagedValue SILGenBuilder::createFormalAccessBeginBorrow(SILLocation loc,
 ManagedValue SILGenBuilder::createMoveValue(SILLocation loc, ManagedValue value,
                                             bool isLexical) {
   assert(value.isPlusOne(SGF) && "Must be +1 to be moved!");
-  CleanupCloner cloner(*this, value);
   auto *mdi =
       createMoveValue(loc, value.forward(getSILGenFunction()), isLexical);
-  return cloner.clone(mdi);
+  // We always want a generic destroy_value cleanup on the moved value, even
+  // if the original had a more specialized cleanup (because it was a trivial
+  // case of an enum or something like that), so that the move checker does
+  // the right thing with the moved value.
+  return SGF.emitManagedRValueWithCleanup(mdi);
 }
 
 ManagedValue

test/SILGen/consume_operator_trivial_value_of_nontrivial_type.swift

@@ -0,0 +1,11 @@
+// RUN: %target-swift-emit-silgen -verify %s
+
+// https://github.com/apple/swift/issues/71608
+func f(x:[Int]?)
+{
+}
+func g()
+{
+    let x:[Int]? = nil
+    f(x: consume x)
+}