diff --git a/src/compute_variable.cpp b/src/compute_variable.cpp
index 0acfd27e4f..edde51dddb 100644
--- a/src/compute_variable.cpp
+++ b/src/compute_variable.cpp
@@ -21,8 +21,6 @@
 
 using namespace LAMMPS_NS;
 
-enum{INDEX,LOOP,EQUAL,WORLD,UNIVERSE,ULOOP,ATOM};  // also in variable.cpp
-
 /* ---------------------------------------------------------------------- */
 
 ComputeVariable::ComputeVariable(LAMMPS *lmp, int narg, char **arg) : 
diff --git a/src/compute_variable_atom.cpp b/src/compute_variable_atom.cpp
index 46457b6b0c..1ff5ca11b3 100644
--- a/src/compute_variable_atom.cpp
+++ b/src/compute_variable_atom.cpp
@@ -21,8 +21,6 @@
 
 using namespace LAMMPS_NS;
 
-enum{INDEX,LOOP,EQUAL,WORLD,UNIVERSE,ULOOP,ATOM};  // also in variable.cpp
-
 /* ---------------------------------------------------------------------- */
 
 ComputeVariableAtom::ComputeVariableAtom(LAMMPS *lmp, int narg, char **arg) :
diff --git a/src/variable.cpp b/src/variable.cpp
index cca6d31046..d2afda384c 100644
--- a/src/variable.cpp
+++ b/src/variable.cpp
@@ -307,6 +307,7 @@ int Variable::next(int narg, char **arg)
 
 /* ----------------------------------------------------------------------
    return ptr to the data text associated with a variable
+   if EQUAL var, evaluates variable and puts result in str
    return NULL if no variable or index is bad, caller must respond
 ------------------------------------------------------------------------- */
 
@@ -829,7 +830,8 @@ double Variable::evaluate(char *str, Tree *tree)
 
 void Variable::build_parse_tree(int ivar)
 {
-  if (style[ivar] != ATOM) error->all("");
+  if (style[ivar] != ATOM)
+    error->all("Cannot build parse tree for non atom style variable");
   ptree = new Tree();
   double tmp = evaluate(data[ivar][0],ptree);
 }