[ConstraintSystem] NFC: Print type variables embedded in common result type

Author: xedin

lib/Sema/CSSimplify.cpp

@@ -8898,9 +8898,11 @@ bool ConstraintSystem::simplifyAppliedOverloadsImpl(
   // If we have a common result type, bind the expected result type to it.
   if (commonResultType && !commonResultType->is<ErrorType>()) {
     if (isDebugMode()) {
+      PrintOptions PO;
+      PO.PrintTypesForDebugging = true;
       llvm::errs().indent(solverState ? solverState->depth * 2 : 0)
         << "(common result type for $T" << fnTypeVar->getID() << " is "
-        << commonResultType.getString()
+        << commonResultType.getString(PO)
         << ")\n";
     }