handle non-FunctionDefinitionNode in Body

com.oracle.truffle.r.nodes.builtin/src/com/oracle/truffle/r/nodes/builtin/base/Body.java

@@ -25,7 +25,10 @@ package com.oracle.truffle.r.nodes.builtin.base;
 import static com.oracle.truffle.r.runtime.builtins.RBehavior.PURE;
 import static com.oracle.truffle.r.runtime.builtins.RBuiltinKind.INTERNAL;
 
+import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.dsl.Specialization;
+import com.oracle.truffle.api.nodes.RootNode;
+import com.oracle.truffle.api.profiles.ConditionProfile;
 import com.oracle.truffle.r.nodes.RASTUtils;
 import com.oracle.truffle.r.nodes.builtin.RBuiltinNode;
 import com.oracle.truffle.r.nodes.function.FunctionDefinitionNode;
@@ -41,9 +44,15 @@ public abstract class Body extends RBuiltinNode {
     }
 
     @Specialization
-    protected Object doBody(RFunction fun) {
-        FunctionDefinitionNode fdn = (FunctionDefinitionNode) fun.getRootNode();
-        return RASTUtils.createLanguageElement(fdn.getBody());
+    protected Object doBody(RFunction fun,
+                    @Cached("createBinaryProfile()") ConditionProfile profile) {
+        RootNode root = fun.getRootNode();
+        if (profile.profile(root instanceof FunctionDefinitionNode)) {
+            FunctionDefinitionNode fdn = (FunctionDefinitionNode) root;
+            return RASTUtils.createLanguageElement(fdn.getBody());
+        } else {
+            return RNull.instance;
+        }
     }
 
     @Specialization(guards = "!isRFunction(fun)")