remove unnecessary Object usages

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

@@ -58,7 +58,7 @@ public class EvalFunctions {
         @CompilationFinal private RFunction function;
 
         @Override
-        public Object[] getParameterNames() {
+        public String[] getParameterNames() {
             return PARAMETER_NAMES;
         }
 
@@ -165,7 +165,7 @@ public class EvalFunctions {
         @SuppressWarnings("hiding") protected static final String[] PARAMETER_NAMES = new String[]{"expr", "envir"};
 
         @Override
-        public Object[] getParameterNames() {
+        public String[] getParameterNames() {
             return PARAMETER_NAMES;
         }
 

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

@@ -47,7 +47,7 @@ public class ForeignFunctions {
         protected static final String[] PARAMETER_NAMES = new String[]{".NAME", "...", "NAOK", "DUP", "PACKAGE", "ENCODING"};
 
         @Override
-        public Object[] getParameterNames() {
+        public String[] getParameterNames() {
             return PARAMETER_NAMES;
         }
 

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

@@ -43,7 +43,7 @@ public class IsListFunctions {
         private static final String[] PARAMETER_NAMES = new String[]{"x"};
 
         @Override
-        public Object[] getParameterNames() {
+        public String[] getParameterNames() {
             return PARAMETER_NAMES;
         }
 

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

@@ -35,7 +35,7 @@ public abstract class IsTypeNode extends RBuiltinNode {
     private static final String[] PARAMETER_NAMES = new String[]{"x"};
 
     @Override
-    public Object[] getParameterNames() {
+    public String[] getParameterNames() {
         return PARAMETER_NAMES;
     }
 

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

@@ -23,10 +23,10 @@ import com.oracle.truffle.r.runtime.ops.*;
 @RBuiltin(name = "prod", kind = RBuiltinKind.PRIMITIVE, parameterNames = {"...", "na.rm"})
 public abstract class Prod extends RBuiltinNode {
 
-    private static final Object[] PARAMETER_NAMES = new Object[]{"..."};
+    private static final String[] PARAMETER_NAMES = new String[]{"..."};
 
     @Override
-    public Object[] getParameterNames() {
+    public String[] getParameterNames() {
         return PARAMETER_NAMES;
     }
 

com.oracle.truffle.r.nodes/src/com/oracle/truffle/r/nodes/access/WriteVariableNode.java

@@ -150,10 +150,10 @@ public abstract class WriteVariableNode extends RNode implements VisibilityContr
 
     public abstract void execute(VirtualFrame frame, Object value);
 
-    @NodeFields({@NodeField(name = "symbol", type = Object.class), @NodeField(name = "mode", type = Mode.class)})
+    @NodeFields({@NodeField(name = "name", type = String.class), @NodeField(name = "mode", type = Mode.class)})
     public abstract static class UnresolvedWriteLocalVariableNode extends WriteVariableNode {
 
-        public abstract Object getSymbol();
+        public abstract String getName();
 
         public abstract Mode getMode();
 
@@ -183,7 +183,7 @@ public abstract class WriteVariableNode extends RNode implements VisibilityContr
 
         private void resolveAndSet(VirtualFrame frame, Object value, FrameSlotKind initialKind) {
             CompilerAsserts.neverPartOfCompilation();
-            FrameSlot frameSlot = frame.getFrameDescriptor().findOrAddFrameSlot(getSymbol(), initialKind);
+            FrameSlot frameSlot = frame.getFrameDescriptor().findOrAddFrameSlot(getName(), initialKind);
             replace(ResolvedWriteLocalVariableNode.create(getRhs(), this.isArgWrite(), frameSlot, getMode())).execute(frame, value);
         }
     }

com.oracle.truffle.r.nodes/src/com/oracle/truffle/r/nodes/builtin/RBuiltinNode.java

@@ -71,7 +71,7 @@ public abstract class RBuiltinNode extends RCallNode implements VisibilityContro
      *
      * TODO This should go away once all builtins are converted to annotation based specification.
      */
-    protected Object[] getParameterNames() {
+    protected String[] getParameterNames() {
         RBuiltin builtin = getRBuiltin();
         return builtin == null ? null : builtin.parameterNames();
     }