SIL: Casts that may be to NSError must use indirect cast instructions.

checked_cast_br promises to maintain RC identity, but a cast from an ErrorType-conforming class to NSError may change the RC identity by bridging. Make sure that potential class-to-NSError casts go through the indirect cast entry points for now. The runtime implementation still needs to be fixed to handle the class-to-NSError case, but this is part of rdar://problem/21116814.

Swift SVN r29089

lib/SILGen/SILGenPattern.cpp

@@ -1452,7 +1452,8 @@ emitSerialCastOperand(SILGenFunction &SGF, SILLocation loc,
   bool requiresAddress = false;
   for (auto &row : rows) {
     CanType targetType = getTargetType(row);
-    if (!canUseScalarCheckedCastInstructions(sourceType, targetType)) {
+    if (!canUseScalarCheckedCastInstructions(SGF.SGM.M,
+                                             sourceType, targetType)) {
       requiresAddress = true;
       break;
     }