[move-only] Move MoveOnlyObjectChecker /before/ MoveOnlyAddressChecker in the pass pipeline and move post checker verification into the MoveOnlyAddressChecker.

The reason why I am doing this is that:

1. There are sometimes copy_value on move only values loaded from memory that
the MoveOnlyAddressChecker needs to eliminate.

2. Previously, the move only address checker did not rewrite copy_value ->
explicit_copy_value if it failed in diagnostics (it did handle load [copy] and
copy_addr though). This could then cause the copy_value elimination verification
in the MoveOnlyObjectChecker to then fail. So this suggested that I needed to
move the verification from the object checkt to the address checker.

3. If we run the verification in the address checker, then the object checker
(which previously ran before the address checker) naturally needed to run
/before/ the address checker.

Author: gottesmm

lib/SILOptimizer/Mandatory/MoveOnlyObjectChecker.cpp

@@ -806,6 +806,9 @@ class MoveOnlyCheckerPass : public SILFunctionTransform {
     if (checker.changed) {
       invalidateAnalysis(SILAnalysis::InvalidationKind::Instructions);
     }
+
+    // NOTE: We validate in the MoveOnlyAddressChecker (which runs after this)
+    // that we eliminated all copy_value and emit errors otherwise.
   }
 };
 

lib/SILOptimizer/PassManager/PassPipeline.cpp

@@ -154,10 +154,14 @@ static void addMandatoryDiagnosticOptPipeline(SILPassPipelinePlan &P) {
   // resolution of nonescaping closure lifetimes to correctly check the use
   // of move-only values as captures in nonescaping closures as borrows.
 
-  // Check noImplicitCopy and move only types for addresses.
-  P.addMoveOnlyAddressChecker();
   // Check noImplicitCopy and move only types for objects
+  //
+  // NOTE: It is important that this is run /before/ move only address checker
+  // since if the address checker emits an error, it will cleanup copy_value of
+  // move only objects meaning that we could lose object level diagnostics.
   P.addMoveOnlyObjectChecker();
+  // Check noImplicitCopy and move only types for addresses.
+  P.addMoveOnlyAddressChecker();
   // Convert last destroy_value to deinits.
   P.addMoveOnlyDeinitInsertion();
   // Lower move only wrapped trivial types.