diff --git a/C/exec.c b/C/exec.c
index 89fa21500..f21b95cf9 100755
--- a/C/exec.c
+++ b/C/exec.c
@@ -1065,7 +1065,7 @@ static Int _user_expand_goal(USES_REGS1) {
   ARG1 = g;
   if ((pe = RepPredProp(Yap_GetPredPropByFunc(FunctorGoalExpansion2, cmod))) &&
       pe->OpcodeOfPred != FAIL_OPCODE && pe->OpcodeOfPred != UNDEF_OPCODE &&
-      Yap_execute_pred(pe, NULL, false PASS_REGS)) {
+      Yap_execute_pred(pe, NULL, true PASS_REGS)) {
     return complete_ge(true, omod, sl, creeping);
   }
   /* system:goal_expansion(A,B) */
@@ -1076,7 +1076,7 @@ static Int _user_expand_goal(USES_REGS1) {
   if ((pe = RepPredProp(
            Yap_GetPredPropByFunc(FunctorGoalExpansion2, SYSTEM_MODULE))) &&
       pe->OpcodeOfPred != FAIL_OPCODE && pe->OpcodeOfPred != UNDEF_OPCODE &&
-      Yap_execute_pred(pe, NULL, false PASS_REGS)) {
+      Yap_execute_pred(pe, NULL, true PASS_REGS)) {
     return complete_ge(true, omod, sl, creeping);
   }
     Yap_ResetException(NULL);
@@ -1087,7 +1087,7 @@ static Int _user_expand_goal(USES_REGS1) {
   if ((pe = RepPredProp(
            Yap_GetPredPropByFunc(FunctorGoalExpansion, USER_MODULE))) &&
       pe->OpcodeOfPred != FAIL_OPCODE && pe->OpcodeOfPred != UNDEF_OPCODE &&
-      Yap_execute_pred(pe, NULL PASS_REGS, false)) {
+      Yap_execute_pred(pe, NULL, true  PASS_REGS)) {
     return complete_ge(true, omod, sl, creeping);
   }
     Yap_ResetException(NULL);
@@ -1101,7 +1101,7 @@ static Int _user_expand_goal(USES_REGS1) {
       (pe = RepPredProp(
            Yap_GetPredPropByFunc(FunctorGoalExpansion2, USER_MODULE))) &&
       pe->OpcodeOfPred != FAIL_OPCODE && pe->OpcodeOfPred != UNDEF_OPCODE &&
-      Yap_execute_pred(pe, NULL PASS_REGS, false)) {
+      Yap_execute_pred(pe, NULL, true PASS_REGS)) {
     return complete_ge(true, omod, sl, creeping);
   }
   Yap_ResetException(NULL);
@@ -1723,13 +1723,6 @@ bool Yap_execute_pred(PredEntry *ppe, CELL *pt, bool pass_ex USES_REGS) {
     /* restore the old environment */
     /* get to previous environment */
     cut_B = (choiceptr)ENV[E_CB];
-    {
-      /* Note that
-         cut_B == (choiceptr)ENV[E_CB] */
-      while (POP_CHOICE_POINT(ENV[E_CB])) {
-        POP_EXECUTE();
-      }
-    }
 #ifdef YAPOR
     CUT_prune_to(cut_B);
 #endif /* YAPOR */
@@ -1754,21 +1747,20 @@ bool Yap_execute_pred(PredEntry *ppe, CELL *pt, bool pass_ex USES_REGS) {
     /* we have failed, and usually we would backtrack to this B,
        trouble is, we may also have a delayed cut to do */
     if (B != NULL)
-
       HB = B->cp_h;
     YENV = ENV;
     // should we catch the exception or pass it through?
-    // We'll pass it through
-    if (pass_ex && Yap_HasException()) {
-        if ((LOCAL_PrologMode & BootMode) || !CurrentModule ) {
-	  Yap_ResetException(LOCAL_ActiveError);
+    // We'll pass it through 
+    if ( Yap_HasException()) {
+      if (pass_ex &&
+	  ((LOCAL_PrologMode & BootMode) || !CurrentModule )) {
+	Yap_ResetException(LOCAL_ActiveError);
+      } else {
+	Yap_RaiseException();
+      }
       return false;
     }
-
-      Yap_RaiseException();
-      return false;
-    }
-    return true;
+   return true;
   } else if (out == 0) {
     P = saved_p;
     CP = saved_cp;
@@ -1786,12 +1778,13 @@ bool Yap_execute_pred(PredEntry *ppe, CELL *pt, bool pass_ex USES_REGS) {
     HB = PROTECT_FROZEN_H(B);
     // should we catch the exception or pass it through?
     // We'll pass it through
-    if (pass_ex) {
-        if ((LOCAL_PrologMode & BootMode) || !CurrentModule ) {
-	  Yap_ResetException(LOCAL_ActiveError);
-      return false;
-    }
-      Yap_RaiseException();
+    if ( Yap_HasException()) {
+      if (pass_ex &&
+	  ((LOCAL_PrologMode & BootMode) || !CurrentModule )) {
+	Yap_ResetException(LOCAL_ActiveError);
+      } else {
+	Yap_RaiseException();
+      }
     }
     return false;
   } else {
diff --git a/C/globals.c b/C/globals.c
index 59be2a42b..0a5031fe2 100644
--- a/C/globals.c
+++ b/C/globals.c
@@ -354,7 +354,7 @@ static inline void clean_dirty_tr(tr_fr_ptr TR0 USES_REGS) {
 #define expand_stack(S0,SP,SF,TYPE)	       \
   { size_t sz = SF-S0, used = SP-S0;	       \
   S0  = Realloc(S0, (1024+sz)*sizeof(TYPE) PASS_REGS);               \
-  SP = S0+used; SF = S0+sz; }
+  SP = S0+used; SF = S0+(1024+sz); }
 
 static int copy_complex_term(register CELL *pt0, register CELL *pt0_end,
                              int share, int copy_att_vars, CELL *ptf,
@@ -808,10 +808,8 @@ error_handler:
       }
       break;
     default: /* temporary space overflow */
-      if (!Yap_ExpandPreAllocCodeSpace(0, NULL, TRUE)) {
-        Yap_Error(RESOURCE_ERROR_AUXILIARY_STACK, TermNil, LOCAL_ErrorMessage);
-        return 0L;
-      }
+      return 0;
+      
     }
   }
   oldH = HR;
diff --git a/C/terms.c b/C/terms.c
index 1229aad3f..8d30e9aae 100644
--- a/C/terms.c
+++ b/C/terms.c
@@ -187,14 +187,9 @@ aux_overflow : {							\
     CELL *ptd0 = to_visit->ptd0;			\
     *ptd0 = to_visit->d0;				\
   }							\
-  LOCAL_Error_TYPE = RESOURCE_ERROR_HEAP;		\
-  LOCAL_Error_Size = (TR - TR0) * sizeof(tr_fr_ptr *);	\
   clean_tr(TR0 PASS_REGS);					\
-  HR = InitialH;						\
-  pop_text_stack(lvl);					\
-  return 0L;							\
-}									\
-goto reset;
+  auxsz += auxsz;\
+     goto reset; }
 
 #define def_trail_overflow()					\
 trail_overflow : {						\
@@ -304,9 +299,8 @@ static int cycles_in_complex_term( CELL *pt0_, CELL *pt0_end_ USES_REGS) {
 
   CELL *pt0, *pt0_end;
   int lvl = push_text_stack();
- size_t auxsz = 1024 * sizeof(struct non_single_struct_t);\
- struct non_single_struct_t *to_visit0=NULL, *to_visit, *to_visit_max;\
- to_visit0 = Malloc(auxsz);
+ size_t auxsz = 1024 * sizeof(struct non_single_struct_t);
+ struct non_single_struct_t *to_visit0=NULL, *to_visit, *to_visit_max;
   CELL *InitialH = HR;
   tr_fr_ptr TR0 = TR;
   
@@ -564,11 +558,28 @@ static Int variable_in_term(USES_REGS1) {
 static Term vars_in_complex_term(CELL *pt0_, CELL *pt0_end_ ,
  Term inp USES_REGS) {
 
-   CELL output = AbsPair(HR);
+  Int count=0;
+  while (!IsVarTerm(inp) && IsPairTerm(inp)) {
+    Term t = HeadOfTerm(inp);
+    if (IsVarTerm(t)) {
+      CELL *ptr = VarOfTerm(t);
+      *ptr = TermFoundVar;
+      TrailTerm(TR++) = t;
+      count++;
+      if (TR > (tr_fr_ptr)LOCAL_TrailTop - 256) {
+       clean_tr(TR - count PASS_REGS);
+       if (!Yap_growtrail(count * sizeof(tr_fr_ptr *), false)) {
+         return false;
+       }
+     }
+   }
+   inp = TailOfTerm(inp);
+ }
+  
+  CELL output = AbsPair(HR);
    WALK_COMPLEX_TERM();
   /* do or pt2 are unbound  */
-  *ptd0 = TermNil;
-  /* leave an empty slot to fill in later */
+
   if (HR + 1024 > ASP) {
     goto global_overflow;
   }
@@ -578,15 +589,13 @@ static Term vars_in_complex_term(CELL *pt0_, CELL *pt0_end_ ,
   /* next make sure noone will see this as a variable again */
   if (TR > (tr_fr_ptr)LOCAL_TrailTop - 256) {
     /* Trail overflow */
-    if (!Yap_growtrail((TR - TR0) * sizeof(tr_fr_ptr *), true)) {
       goto trail_overflow;
-    }
   }
   TrailTerm(TR++) = (CELL)ptd0;
-
+  *ptd0 = TermFoundVar;
   END_WALK();
 
-  clean_tr(TR0 PASS_REGS);
+  clean_tr(TR0-count PASS_REGS);
   pop_text_stack(lvl);
 
   if (HR != InitialH) {
@@ -594,7 +603,7 @@ static Term vars_in_complex_term(CELL *pt0_, CELL *pt0_end_ ,
     Term t2 = Deref(inp);
     if (IsVarTerm(t2)) {
       RESET_VARIABLE(HR - 1);
-      Yap_unify((CELL)(HR - 1), inp);
+      Yap_unify((CELL)(HR - 1), t2);
     } else {
       HR[-1] = t2; /* don't need to trail */
     }
@@ -621,30 +630,10 @@ static Int variables_in_term(
 			     USES_REGS1) /* variables in term t		 */
 {
   Term out, inp;
-  int count;
 
-  restart:
-  count = 0;
   inp = Deref(ARG2);
-  while (!IsVarTerm(inp) && IsPairTerm(inp)) {
-    Term t = HeadOfTerm(inp);
-    if (IsVarTerm(t)) {
-      CELL *ptr = VarOfTerm(t);
-      *ptr = TermFoundVar;
-      TrailTerm(TR++) = t;
-      count++;
-      if (TR > (tr_fr_ptr)LOCAL_TrailTop - 256) {
-       clean_tr(TR - count PASS_REGS);
-       if (!Yap_growtrail(count * sizeof(tr_fr_ptr *), false)) {
-         return false;
-       }
-       goto restart;
-     }
-   }
-   inp = TailOfTerm(inp);
- }
   Term t = Deref(ARG1);
-  out = vars_in_complex_term(&(t)-1, &(t), ARG2 PASS_REGS);
+  out = vars_in_complex_term(&(t)-1, &(t), inp PASS_REGS);
 return Yap_unify(ARG3, out);
 }
 
@@ -701,6 +690,22 @@ Term Yap_TermVariables(
  return out;
 }
 
+static Term Yap_TermAddVariables(
+				 Term t, Term vs USES_REGS) /* variables in term t		 */
+{
+  Term out;
+
+     t = Deref(t);
+    if (IsVarTerm(t)) {
+      return MkPairTerm(t, TermNil);
+    } else if (IsPrimitiveTerm(t)) {
+      return TermNil;
+    } else {
+      out = vars_in_complex_term(&(t)-1, &(t), vs PASS_REGS);
+    }
+ return out;
+}
+
 /** @pred  term_variables(? _Term_, - _Variables_) is iso
 
 
@@ -715,7 +720,6 @@ static Int term_variables(
 			    USES_REGS1) /* variables in term t		 */
 {
   Term out;
-  cs[1]++;
   if (!Yap_IsListOrPartialListTerm(ARG2)) {
     Yap_ThrowError(TYPE_ERROR_LIST, ARG2, "term_variables/2");
     return false;
@@ -803,7 +807,7 @@ static Int term_attvars(USES_REGS1) /* variables in term t		 */
  */
 static Term new_vars_in_complex_term(
  CELL *pt0_, CELL *pt0_end_ , Term inp USES_REGS) {
-  HB = ASP;
+  Int n=0;
   CELL output = TermNil;
   {
     tr_fr_ptr myTR0 = TR;
@@ -811,13 +815,14 @@ static Term new_vars_in_complex_term(
       int lvl = push_text_stack();
       Term t = HeadOfTerm(inp);
       if (IsVarTerm(t)) {
-       YapBind(VarOfTerm(t), TermFoundVar);
+	n++;
+    TrailTerm(TR++) = t;
+    *VarOfTerm(t) = TermFoundVar;
        if ((tr_fr_ptr)LOCAL_TrailTop - TR < 1024) {
 
-         if (!Yap_growtrail((TR - myTR0) * sizeof(tr_fr_ptr *), true)) {
+         if (!Yap_growtrail(n * sizeof(tr_fr_ptr *), true)) {
            goto trail_overflow;
          }
-         pop_text_stack(lvl);
        }
      }
      inp = TailOfTerm(inp);
@@ -825,11 +830,10 @@ static Term new_vars_in_complex_term(
  }
  WALK_COMPLEX_TERM();
  output = MkPairTerm((CELL)ptd0, output);
- YapBind(ptd0, TermFoundVar);
+    TrailTerm(TR++) = *ptd0;
+    *ptd0 = TermFoundVar;
  if ((tr_fr_ptr)LOCAL_TrailTop - TR < 1024) {
-  if (!Yap_growtrail((TR - TR0) * sizeof(tr_fr_ptr *), true)) {
     goto trail_overflow;
-  }
 }
   /* leave an empty slot to fill in later */
 if (HR + 1024 > ASP) {
@@ -837,9 +841,9 @@ if (HR + 1024 > ASP) {
 }
 END_WALK();
 
-clean_tr(TR0 PASS_REGS);
+clean_tr(TR0-n PASS_REGS);
 pop_text_stack(lvl);
-HB = B->cp_h;
+
 return output;
 
 def_aux_overflow();
@@ -888,7 +892,7 @@ if (d0 == TermFoundVar) {			\
 
 static Term vars_within_complex_term(
  CELL *pt0_, CELL *pt0_end_, Term inp USES_REGS) {
-
+  Int n=0;
   CELL output = AbsPair(HR);
  
   while (!IsVarTerm(inp) && IsPairTerm(inp)) {
@@ -897,9 +901,10 @@ static Term vars_within_complex_term(
     if (IsVarTerm(t)) {
       CELL *ptr = VarOfTerm(t);
       *ptr = TermFoundVar;
+      n++;
       TrailTerm(TR++) = t;
       if (TR > (tr_fr_ptr)LOCAL_TrailTop - 256) {
-       Yap_growtrail((TR - myTR0) * sizeof(tr_fr_ptr *), true);
+       Yap_growtrail(2*n * sizeof(tr_fr_ptr *), true);
      }
    }
    inp = TailOfTerm(inp);
@@ -909,7 +914,7 @@ static Term vars_within_complex_term(
  goto restart;
  END_WALK();
 
- clean_tr(TR0 PASS_REGS);
+ clean_tr(TR0-n PASS_REGS);
  pop_text_stack(lvl);
  if (HR != InitialH) {
   HR[-1] = TermNil;
@@ -946,104 +951,37 @@ static Int p_variables_within_term(USES_REGS1) /* variables within term t */
   return Yap_unify(ARG3, out);
 }
 
-static Term free_vars_in_complex_term(CELL * pt0_, CELL * pt0_end_
- USES_REGS) {
-  Term o = TermNil;
-  WALK_COMPLEX_TERM();
-  /* do or pt2 are unbound  */
-  *ptd0 = TermNil;
-  /* leave an empty slot to fill in later */
-  if (HR + 1024 > ASP) {
-    o = TermNil;
-    goto global_overflow;
-  }
-  HR[0] = (CELL)ptd0;
-  HR[1] = o;
-  o = AbsPair(HR);
-  HR += 2;
-  /* next make sure noone will see this as a variable again */
-  if (TR > (tr_fr_ptr)LOCAL_TrailTop - 256) {
-    /* Trail overflow */
-    if (!Yap_growtrail((TR - TR0) * sizeof(tr_fr_ptr *), true)) {
-      goto trail_overflow;
-    }
-  }
-  TrailTerm(TR++) = (CELL)ptd0;
-  END_WALK();
-
-  clean_tr(TR0 PASS_REGS);
-  pop_text_stack(lvl);
-  return o;
-
-  def_aux_overflow();
-
-  def_trail_overflow();
-
-  def_global_overflow();
-}
-
-static Term bind_vars_in_complex_term(CELL * pt0_, CELL * pt0_end_ USES_REGS) {
-  WALK_COMPLEX_TERM();
-  /* do or pt2 are unbound  */
-  *ptd0 = TermFoundVar;
-  /* next make sure noone will see this as a variable again */
-  if (TR > (tr_fr_ptr)LOCAL_TrailTop - 256) {
-    /* Trail overflow */
-    if (!Yap_growtrail((TR - TR0) * sizeof(tr_fr_ptr *), true)) {
-      while (to_visit > to_visit0) {
-       to_visit--;
-       CELL *ptd0 = to_visit->ptd0;
-       *ptd0 = to_visit->d0;
-     }
-     goto trail_overflow;
-   }
- }
- TrailTerm(TR++) = (CELL)ptd0;
-
- END_WALK();
-
- pop_text_stack(lvl);
- return TermNil;
-
- def_aux_overflow();
-
- def_trail_overflow();
-}
-
-static Int p_free_variables_in_term(
-				    USES_REGS1) /* variables within term t		 */
+/* variables within term t		 */
+static Int free_variables_in_term(
+				    USES_REGS1)
 {
   Term out;
   Term t, t0;
   Term found_module = 0L;
+  Term vlist = TermNil;
 
-     tr_fr_ptr TR0 = TR;
-
-    t = t0 = Deref(ARG1);
-    while (!IsVarTerm(t) && IsApplTerm(t)) {
-      Functor f = FunctorOfTerm(t);
-      if (f == FunctorHat) {
-       out = bind_vars_in_complex_term(RepAppl(t), RepAppl(t) + 1,
-         TR0 PASS_REGS);
-       if (out == 0L) {
-         goto trail_overflow;
-       }
-     } else if (f == FunctorModule) {
-       found_module = ArgOfTerm(1, t);
-     } else if (f == FunctorCall) {
-       t = ArgOfTerm(1, t);
-     } else if (f == FunctorExecuteInMod) {
-       found_module = ArgOfTerm(2, t);
-       t = ArgOfTerm(1, t);
-     } else {
-       break;
-     }
-     t = ArgOfTerm(2, t);
+  t = t0 = Deref(ARG1);
+  Int delta = 0;
+  while (!IsVarTerm(t) && IsApplTerm(t)) {
+    Functor f = FunctorOfTerm(t);
+    if (f == FunctorHat) {
+      vlist = Yap_TermAddVariables(ArgOfTerm(1,t), vlist PASS_REGS);
+    } else if (f == FunctorModule) {
+      found_module = ArgOfTerm(1, t);
+    } else if (f == FunctorCall) {
+      t = ArgOfTerm(1, t);
+    } else if (f == FunctorExecuteInMod) {
+      found_module = ArgOfTerm(2, t);
+      t = ArgOfTerm(1, t);
+    } else {
+      break;
+    }
+    t = ArgOfTerm(2, t);
    }
    if (IsPrimitiveTerm(t))
     out = TermNil;
   else {
-    out = free_vars_in_complex_term(&(t)-1, &(t), TR0 PASS_REGS);
+    out = new_vars_in_complex_term(&(t)-1, &(t), vlist PASS_REGS);
   }
   
 if (found_module && t != t0) {
@@ -1055,43 +993,42 @@ if (found_module && t != t0) {
 return Yap_unify(ARG2, t) && Yap_unify(ARG3, out);
 }
 
-#define FOUND_VAR_AGAIN()			\
-if (d0 == TermFoundVar) {			\
-  CELL *pt2 = pt0;				\
-  while (IsVarTerm(*pt2))			\
-    pt2 = (CELL *)(*pt2);			\
-  HR[1] = AbsPair(HR + 2);			\
-  HR[0] = (CELL)pt2;				\
-  HR += 2;					\
-  *pt2 = TermRefoundVar;			\
-}
+#define FOUND_VAR_AGAIN()   \
+  if (d0 == TermFoundVar)   \
+  {                         \
+    HR[0] = (CELL)ptd0;     \
+    HR[1] = AbsPair(HR + 2); \
+    HR += 2;                \
+    *ptd0 = TermRefoundVar; \
+  }
+
+static Term non_singletons_in_complex_term(CELL * pt0_,
+  CELL * pt0_end_ USES_REGS) {
 
-static Term non_singletons_in_complex_term(CELL * pt0,
-  CELL * pt0_end USES_REGS) {
-  tr_fr_ptr TR0 = TR;
-  CELL *InitialH = HR;
-  HB = (CELL *)ASP;
-  CELL output = AbsPair(HR);
-  int lvl = push_text_stack();
   WALK_COMPLEX_TERM__({}, {}, FOUND_VAR_AGAIN());
   /* do or pt2 are unbound  */
-  YapBind(ptd0, TermFoundVar);
-  goto restart;
+  *ptd0 = TermFoundVar;
+  /* next make sure noone will see this as a variable again */
+  if (TR > (tr_fr_ptr)LOCAL_TrailTop - 256)
+  {
+    goto trail_overflow;
+  }
+  TrailTerm(TR++) = (CELL)ptd0;
   END_WALK();
 
   clean_tr(TR0 PASS_REGS);
 
   pop_text_stack(lvl);
-  HB = (CELL *)B->cp_b;
   if (HR != InitialH) {
     /* close the list */
     HR[-1] = Deref(ARG2);
-    return output;
+    return AbsPair(InitialH);
   } else {
     return ARG2;
   }
 
   def_aux_overflow();
+  def_trail_overflow();
 }
 
 static Int p_non_singletons_in_term(
@@ -1108,7 +1045,8 @@ static Int p_non_singletons_in_term(
     } else {
       out = non_singletons_in_complex_term(&(t)-1, &(t)PASS_REGS);
     }
- }
+    return Yap_unify(ARG3,out);
+}
 
 static Term numbervar(Int me USES_REGS) {
   Term ts[1];
@@ -1133,7 +1071,7 @@ if (singles) {				\
   goto restart;				\
 }
 
-static Int numbervars_in_complex_term(CELL * pt0, CELL * pt0_end, Int numbv,
+static Int numbervars_in_complex_term(CELL * pt0_, CELL * pt0_end_, Int numbv,
   int singles USES_REGS) {
 
   WALK_COMPLEX_TERM__({}, {}, {});
@@ -1216,7 +1154,7 @@ if (FunctorOfTerm(d0) == FunctorDollarVar) {			\
   goto restart;						\
 }
 
-static int max_numbered_var(CELL * pt0, CELL * pt0_end,
+static int max_numbered_var(CELL * pt0_, CELL * pt0_end_,
  Int * maxp USES_REGS) {
 
   WALK_COMPLEX_TERM__({}, MAX_NUMBERED, {});
@@ -1448,7 +1386,8 @@ void Yap_InitTermCPreds(void) {
   Yap_InitCPred("term_variables", 3, term_variables3, 0);
   Yap_InitCPred("$variables_in_term", 3, variables_in_term, 0);
 
-  Yap_InitCPred("$free_variables_in_term", 3, p_free_variables_in_term, 0);
+  Yap_InitCPred("$free_variables_in_term", 3, free_variables_in_term, 0);
+  Yap_InitCPred("free_variables_in_term", 3, free_variables_in_term, 0);
 
   Yap_InitCPred("term_attvars", 2, term_attvars, 0);
 
diff --git a/C/utilpreds.c b/C/utilpreds.c
index 4ebf53655..85633d85b 100644
--- a/C/utilpreds.c
+++ b/C/utilpreds.c
@@ -395,9 +395,9 @@ int Yap_copy_complex_term(register CELL *pt0, register CELL *pt0_end,
 	RESET_VARIABLE(ptf);
 	*ptd0 = (CELL)ptf;
 	ptf++;
-	if ((ADDR)TR > LOCAL_TrailTop - 16)
+  TrailTerm(TR++) = (CELL)ptd0;
+  if ((ADDR)TR > LOCAL_TrailTop - 16)
 	  goto trail_overflow;
-
     }
   }
   
@@ -521,7 +521,7 @@ CopyTerm(Term inp, UInt arity, int share, int newattvs USES_REGS) {
 Term
 Yap_CopyTerm(Term inp) {
   CACHE_REGS
-    return CopyTerm(inp, 0, TRUE, TRUE PASS_REGS);
+    return CopyTerm(inp, 0, false, TRUE PASS_REGS);
 }
 
 Term
@@ -533,7 +533,7 @@ Yap_CopyTermNoShare(Term inp) {
 static Int
 p_copy_term( USES_REGS1 )		/* copy term t to a new instance  */
 {
-  Term t = CopyTerm(ARG1, 2, TRUE, TRUE PASS_REGS);
+  Term t = CopyTerm(ARG1, 2, false, TRUE PASS_REGS);
   if (t == 0L)
     return FALSE;
   /* be careful, there may be a stack shift here */
diff --git a/pl/debug.yap b/pl/debug.yap
index ca648226f..cc6abede9 100644
--- a/pl/debug.yap
+++ b/pl/debug.yap
@@ -16,7 +16,7 @@
 *************************************************************************/
 
 
-:- system_module( '$_debug', [], ['$trace_query'/4,
+:- system_module( '$_debug', [], ['$trace_plan'/4,
         '$init_debugger'/0,
         '$skipeol'/1]).
 
@@ -254,7 +254,7 @@ be lost.
    *
    * The debugger is an interpreter. with main predicates:
    * - $trace: this is the API
-   * - $trace_query: reduce a query to a goal
+   * - $trace_plan: reduce a query to a goal
    * - $trace_goal: execute:
    *    + using the source, Luke
    *    + hooking into the WAM procedure call mechanism
@@ -308,7 +308,7 @@ be lost.
      '$execute_nonstop'(G,Mod).
 '$trace'(Mod:G) :-
     '$$save_by'(CP),
-    '$trace_query'(G, Mod, CP, G, EG),
+    '$trace_plan'(G, Mod, CP, G, EG),
     gated_call(
 	'$debugger_io',
 	EG,
@@ -415,42 +415,54 @@ be lost.
 
 
 '$trace_meta_call'( G, M, CP ) :-
-    '$trace_query'(G, M, CP, G, EG ),
+    '$trace_plan'(G, M, CP, G, EG ),
     call(EG).
 
-%% @pred '$trace_query'( +G, +M, +CP, +Expanded)
+%% @pred '$trace_plan'( +G, +M, +CP, +Expanded)
 %
 % debug a complex query
 %
-'$trace_query'(V, M, _CP, _, call(M:V)) :-
+'$trace_plan'(V, M, _CP, _, call(M:V)) :-
     var(V), !.
-'$trace_query'(!, _, CP, _, '$$cut_by'(CP)) :-
+'$trace_plan'(!, _, CP, _, '$$cut_by'(CP)) :-
     !.
-'$trace_query'('$cut_by'(M), _, _, _, '$$cut_by'(M)) :-
+'$trace_plan'('$cut_by'(M), _, _, _, '$$cut_by'(M)) :-
     !.
-'$trace_query'('$$cut_by'(M), _, _, _, '$$cut_by'(M)) :-
+'$trace_plan'('$$cut_by'(M), _, _, _, '$$cut_by'(M)) :-
     !.
-'$trace_query'(true, _, _, _, true) :- !.
-'$trace_query'(fail, _, _, _, '$trace'(fail)) :- !.
-'$trace_query'(M:G, _, CP,S, Expanded) :-
-    !,
-    '$yap_strip_module'(M:G, M0, G0),
-    '$trace_query'(G0, M0, CP,S, Expanded ).
-'$trace_query'((A,B), M, CP, S, (EA,EB)) :- !,
-    '$trace_query'(A, M, CP, S, EA),
-    '$trace_query'(B, M, CP, S, EB).
-'$trace_query'((A->B), M, CP, S, (EA->EB)) :- !,
-    '$trace_query'(A, M, CP, S, EA),
-    '$trace_query'(B, M, CP, S, EB).
-'$trace_query'((A;B), M, CP, S, (EA;EB)) :- !,
-	'$trace_query'(A, M, CP, S, EA),
-	'$trace_query'(B, M, CP, S, EB).
-'$trace_query'((A|B), M, CP, S, (EA|EB)) :- !,
-	'$trace_query'(A, M, CP, S, EA),
-	'$trace_query'(B, M, CP, S, EB).
-'$trace_query'((\+ A), M, CP, S, (\+ EA)) :- !,
-	'$trace_query'(A, M, CP, S, EA).
-'$trace_query'(G, M, _CP, _, (
+'$trace_plan'(true, _, _, _, true) :- !.
+'$trace_plan'(fail, _, _, _, '$trace'(fail)) :- !.
+'$trace_plan'((A,B), M, CP, S, (EA,EB)) :- !,
+    '$trace_plan'(A, M, CP, S, EA),
+    '$trace_plan'(B, M, CP, S, EB).
+'$trace_plan'((A->B), M, CP, S, (EA->EB)) :- !,
+    '$trace_plan'(A, M, CP, S, EA),
+    '$trace_plan'(B, M, CP, S, EB).
+'$trace_plan'((A;B), M, CP, S, (EA;EB)) :- !,
+	'$trace_plan'(A, M, CP, S, EA),
+	'$trace_plan'(B, M, CP, S, EB).
+'$trace_plan'((A|B), M, CP, S, (EA|EB)) :- !,
+	'$trace_plan'(A, M, CP, S, EA),
+	'$trace_plan'(B, M, CP, S, EB).
+	'$trace_plan'(C, M, CP, S, EC),
+'$trace_plan'((A->*B), M, CP, S, (EA->EB)) :- !,
+	'$trace_plan'(A, M, CP, S, EA),
+	'$trace_plan'(B, M, CP, S, EB).
+'$trace_plan'((A->*B;C), M, CP, S, (EA->EB;EC)) :- !,
+	'$trace_plan'(A, M, CP, S, EA),
+	'$trace_plan'(B, M, CP, S, EB),
+	'$trace_plan'(C, M, CP, S, EC).
+'$trace_plan'(if(A,B,C), M, CP, S, (EA->EB;EC)) :- !,
+	'$trace_plan'(A, M, CP, S, EA),
+	'$trace_plan'(B, M, CP, S, EB),
+	'$trace_plan'(C, M, CP, S, EC).
+'$trace_plan'((\+ A), M, CP, S, ( EA -> fail ; true)) :- !,
+	'$trace_plan'(A, M, CP, S, EA).
+'$trace_plan'(once(A), M, CP, S, ( EA ->  true)) :- !,
+	'$trace_plan'(A, M, CP, S, EA).
+'$trace_plan'(ignore(A), M, CP, S, ( EA -> true; true)) :- !,
+	'$trace_plan'(A, M, CP, S, EA).
+'$trace_plan'(G, M, _CP, _, (
         % spy a literal
 	'$id_goal'(L),
         catch(
@@ -487,9 +499,9 @@ be lost.
 	).
 % meta system
 '$trace_goal'(G, M, GoalNumber, H) :-
-        '$is_metapredicate'(G, prolog),
-        !,
-        '$debugger_expand_meta_call'(M:G, [], G1),
+    '$is_metapredicate'(G, prolog),
+    !,
+    '$debugger_expand_meta_call'(M:G, [], G1),
 	strip_module(G1, MF, NG),
 	gated_call(
 		   '$enter_trace'(GoalNumber, G, M, H),
@@ -604,7 +616,7 @@ be lost.
     '$$save_by'(CP),
     clause(M:G, Cl, _),
     '$retry_clause'(GoalNumber, G, M, Info, X),
-    '$trace_query'(Cl, M, CP, Cl, ECl),
+    '$trace_plan'(Cl, M, CP, Cl, ECl),
     '$execute0'(ECl,M).
 
 '$creep_step'(GoalNumber, G, M, Info) :-
@@ -654,7 +666,7 @@ be lost.
 
 
 %%% - abort: forward throw while the call is newer than goal
-%% @pred '$re_trace_query'( Exception, +Goal, +Mod, +GoalID )
+%% @pred '$re_trace_plan'( Exception, +Goal, +Mod, +GoalID )
 %
 % debugger code for exceptions. Recognised cases are:
 %   - abort always forwarded
@@ -1046,10 +1058,10 @@ be lost.
 '$cps'([]).
 
 
-'$debugger_skip_trace_query'([CP|CPs],CPs1) :-
-	yap_hacks:choicepoint(CP,_,prolog,'$trace_query',4,(_;_),_), !,
-	'$debugger_skip_trace_query'(CPs,CPs1).
-'$debugger_skip_trace_query'(CPs,CPs).
+'$debugger_skip_trace_plan'([CP|CPs],CPs1) :-
+	yap_hacks:choicepoint(CP,_,prolog,'$trace_plan',4,(_;_),_), !,
+	'$debugger_skip_trace_plan'(CPs,CPs1).
+'$debugger_skip_trace_plan'(CPs,CPs).
 
 '$debugger_skip_traces'([CP|CPs],CPs1) :-
 	yap_hacks:choicepoint(CP,_,prolog,'$port',4,(_;_),_), !,
diff --git a/pl/setof.yap b/pl/setof.yap
index 5ad05131c..118c65a2e 100644
--- a/pl/setof.yap
+++ b/pl/setof.yap
@@ -230,6 +230,7 @@ bagof(Template, Generator, Bag) :-
 '$bagof'(Template, Generator, Bag) :-
 	'$free_variables_in_term'(Template^Generator, StrippedGenerator, Key),
 	%format('TemplateV=~w v=~w ~w~n',[TemplateV,Key, StrippedGenerator]),
+
 	( Key \== '$' ->
 		'$findall_with_common_vars'(Key-Template, StrippedGenerator, Bags0),
 		'$keysort'(Bags0, Bags),
diff --git a/pl/top.yap b/pl/top.yap
index 13197f25c..3f84a9c56 100644
--- a/pl/top.yap
+++ b/pl/top.yap
@@ -295,7 +295,7 @@ live :-
      '$write_answer'(Vs, LGs, Written),
 	  '$write_query_answer_true'(Written),
 	  (
-	   '$prompt_alternatives_on'(determinism), CP == NCP, DCP = 0
+	   yap_flag(prompt_alternatives_on,determinism), CP == NCP, DCP = 0
 	   ->
 	   format(user_error, '.~n', []),
 	   !
diff --git a/regression/cyclics.yap b/regression/cyclics.yap
index 120568cd4..19c19ef9b 100644
--- a/regression/cyclics.yap
+++ b/regression/cyclics.yap
@@ -13,7 +13,7 @@ main :-
 
 test( cyclic_term(X), [X]).
 test( ground(X), [X]).
-test( (variables_in_term(X, O), writeln(X=O) ), [X, [], O]).
+test( (term_variables(X, O), writeln(X=O) ), [X, [], O]).
 test( (new_variables_in_term(L,X, O), writeln(X+L=O) ), [X, L, O]).
 test( (variables_within_term(L,X, O), writeln(X+L=O) ), [X, L, O]).
 test( writeln(X), [X]).