Fix R in databases for functions

com.oracle.truffle.r.engine/src/com/oracle/truffle/r/engine/TruffleRLanguageImpl.java

@@ -267,7 +267,13 @@ public final class TruffleRLanguageImpl extends TruffleRLanguage {
             final org.graalvm.polyglot.Source source = org.graalvm.polyglot.Source.newBuilder("R", program, "mySrc").build();
             final Value result = rContext.eval(source);
             final Object rValue = QIRInterface.getRValueFromTruffle(result);
-            final RValue res = rValue instanceof Serializable ? new RValue((Serializable) rValue) : (RValue) rValue;
+            final RValue res;
+            if (rValue instanceof Serializable)
+                res = new RValue((Serializable) rValue);
+            else if (rValue instanceof RValue)
+                res = (RValue) rValue;
+            else
+                res = new RValue(result.getSourceLocation().getCharacters().toString());
             valueCache.put(program, res);
             return res;
         } catch (Exception e) {