diff --git a/src/c/array.d b/src/c/array.d
index 8bdbc4d4b..4ff06509d 100644
--- a/src/c/array.d
+++ b/src/c/array.d
@@ -84,10 +84,10 @@ checked_index(cl_object function, cl_object a, int which, cl_object index,
               cl_index nonincl_limit)
 {
         cl_index output;
-        if (ecl_unlikely(!ECL_FIXNUMP(index) || ecl_fixnum_minusp(index)))
+        unlikely_if (!ECL_FIXNUMP(index) || ecl_fixnum_minusp(index))
                 FEwrong_index(function, a, which, index, nonincl_limit);
         output = fix(index);
-        if (ecl_unlikely(output >= nonincl_limit))
+        unlikely_if (output >= nonincl_limit)
                 FEwrong_index(function, a, which, index, nonincl_limit);
         return output;
 }
diff --git a/src/c/error.d b/src/c/error.d
index 21123a53a..3c43e7d93 100644
--- a/src/c/error.d
+++ b/src/c/error.d
@@ -345,14 +345,13 @@ FEwrong_index(cl_object function, cl_object a, int which, cl_object ndx,
         if (!Null(function) && env->ihs_top && env->ihs_top->function != function) {
                 ecl_ihs_push(env,&tmp_ihs,function,Cnil);
         }        
-        si_signal_simple_error(8,
-                               @'type-error', /* condition name */
-                               Cnil, /* not correctable */
-                               message, /* format control */
-                               cl_list(5, function, MAKE_FIXNUM(which+1), ndx,
-                                       a, type),
-                               @':expected-type', type,
-                               @':datum', ndx);
+        cl_error(9,
+                 @'simple-type-error', /* condition name */
+                 @':format-control', message,
+                 @':format-arguments',
+                 cl_list(5, function, MAKE_FIXNUM(which+1), a, ndx, type),
+                 @':expected-type', type,
+                 @':datum', ndx);
 }
 
 void
@@ -457,12 +456,6 @@ universal_error_handler(cl_object continue_string, cl_object datum,
 	ecl_internal_error("\nLisp initialization error.\n");
 }
 
-void
-FEillegal_index(cl_object x, cl_object i)
-{
-	FEerror("~S is an illegal index to ~S.", 2, i, x);
-}
-
 void
 FEdivision_by_zero(cl_object x, cl_object y)
 {
diff --git a/src/c/instance.d b/src/c/instance.d
index 0f7d6ddc7..d6ee23c47 100644
--- a/src/c/instance.d
+++ b/src/c/instance.d
@@ -79,7 +79,7 @@ ecl_instance_ref(cl_object x, cl_fixnum i)
 	if (ecl_unlikely(!ECL_INSTANCEP(x)))
                 FEwrong_type_nth_arg(@[si::instance-ref], 1, x, @[ext::instance]);
 	if (ecl_unlikely(i < 0 || i >= (cl_fixnum)x->instance.length))
-	        FEtype_error_index(x, MAKE_FIXNUM(i));
+	        FEtype_error_index(x, i);
 	return(x->instance.slots[i]);
 }
 
@@ -118,7 +118,7 @@ ecl_instance_set(cl_object x, cl_fixnum i, cl_object v)
         if (ecl_unlikely(!ECL_INSTANCEP(x)))
                 FEwrong_type_nth_arg(@[si::instance-set], 1, x, @[ext::instance]);
 	if (ecl_unlikely(i >= x->instance.length || i < 0))
-	        FEtype_error_index(x, MAKE_FIXNUM(i));
+	        FEtype_error_index(x, i);
 	x->instance.slots[i] = v;
 	return(v);
 }
diff --git a/src/c/list.d b/src/c/list.d
index c0ca74e89..2c20fd3c3 100644
--- a/src/c/list.d
+++ b/src/c/list.d
@@ -400,7 +400,7 @@ cl_object
 ecl_nth(cl_fixnum n, cl_object x)
 {
 	if (n < 0)
-		FEtype_error_index(x, MAKE_FIXNUM(n));
+		FEtype_error_index(x, n);
 	/* INV: No need to check for circularity since we visit
 	   at most `n' conses */
 	for (; n > 0 && CONSP(x); n--)
@@ -422,7 +422,7 @@ cl_object
 ecl_nthcdr(cl_fixnum n, cl_object x)
 {
 	if (n < 0)
-		FEtype_error_index(x, MAKE_FIXNUM(n));
+		FEtype_error_index(x, n);
 	while (n-- > 0 && !Null(x)) {
 		if (LISTP(x)) {
 			x = ECL_CONS_CDR(x);
diff --git a/src/c/sequence.d b/src/c/sequence.d
index 7a075a6c1..63a8f001e 100644
--- a/src/c/sequence.d
+++ b/src/c/sequence.d
@@ -98,7 +98,7 @@ ecl_elt(cl_object seq, cl_fixnum index)
 		FEtype_error_sequence(seq);
 	}
 E:
-	FEtype_error_index(seq, MAKE_FIXNUM(index));
+	FEtype_error_index(seq, index);
 }
 
 cl_object
@@ -140,7 +140,7 @@ ecl_elt_set(cl_object seq, cl_fixnum index, cl_object val)
 		FEtype_error_sequence(seq);
 	}
 E:
-	FEtype_error_index(seq, MAKE_FIXNUM(index));
+	FEtype_error_index(seq, index);
 }
 
 cl_object
diff --git a/src/c/string.d b/src/c/string.d
index 2378771d6..7ab451bdb 100644
--- a/src/c/string.d
+++ b/src/c/string.d
@@ -311,12 +311,12 @@ ecl_char(cl_object object, cl_index index)
 #ifdef ECL_UNICODE
 	case t_string:
 		if (index >= object->string.dim)
-			FEillegal_index(object, MAKE_FIXNUM(index));
+			FEtype_error_index(object, index);
 		return object->string.self[index];
 #endif
 	case t_base_string:
 		if (index >= object->base_string.dim)
-			FEillegal_index(object, MAKE_FIXNUM(index));
+			FEtype_error_index(object, index);
 		return object->base_string.self[index];
 	default:
                 FEwrong_type_nth_arg(@[char],1,object,@[string]);
@@ -340,12 +340,12 @@ ecl_char_set(cl_object object, cl_index index, ecl_character value)
 #ifdef ECL_UNICODE
 	case t_string:
 		if (index >= object->string.dim)
-			FEillegal_index(object, MAKE_FIXNUM(index));
+			FEtype_error_index(object, index);
 		return object->string.self[index] = value;
 #endif
 	case t_base_string:
 		if (index >= object->base_string.dim)
-			FEillegal_index(object, MAKE_FIXNUM(index));
+			FEtype_error_index(object, index);
 		return object->base_string.self[index] = value;
 	default:
                 FEwrong_type_nth_arg(@[si::char-set],1,object,@[string]);
diff --git a/src/c/typespec.d b/src/c/typespec.d
index f9bd882d0..9500d2526 100644
--- a/src/c/typespec.d
+++ b/src/c/typespec.d
@@ -49,13 +49,14 @@ FEcircular_list(cl_object x)
 }
 
 void
-FEtype_error_index(cl_object seq, cl_object ndx)
+FEtype_error_index(cl_object seq, cl_fixnum ndx)
 {
+        cl_object n = MAKE_FIXNUM(ndx);
 	cl_error(9, @'simple-type-error', @':format-control',
 		    make_constant_base_string("~S is not a valid index into the object ~S"),
-		    @':format-arguments', cl_list(2, ndx, seq),
+		    @':format-arguments', cl_list(2, n, seq),
 		    @':expected-type', cl_list(3, @'integer', MAKE_FIXNUM(0), MAKE_FIXNUM(ecl_length(seq)-1)),
-		    @':datum', ndx);
+		    @':datum', n);
 }
 
 void
diff --git a/src/h/external.h b/src/h/external.h
index a55bd03cd..0ab99e68a 100755
--- a/src/h/external.h
+++ b/src/h/external.h
@@ -576,7 +576,6 @@ extern ECL_API void FEinvalid_function(cl_object obj) ecl_attr_noreturn;
 extern ECL_API void FEinvalid_function_name(cl_object obj) ecl_attr_noreturn;
 extern ECL_API void FEprint_not_readable(cl_object obj) ecl_attr_noreturn;
 extern ECL_API cl_object CEerror(cl_object c, const char *err_str, int narg, ...);
-extern ECL_API void FEillegal_index(cl_object x, cl_object i) ecl_attr_noreturn;
 extern ECL_API void FElibc_error(const char *msg, int narg, ...) ecl_attr_noreturn;
 #if defined(ECL_MS_WINDOWS_HOST) || defined(cygwin)
 extern ECL_API void FEwin32_error(const char *msg, int narg, ...) ecl_attr_noreturn;
@@ -1797,7 +1796,7 @@ extern ECL_API void FEtype_error_proper_list(cl_object x) ecl_attr_noreturn;
 extern ECL_API void FEtype_error_sequence(cl_object x) ecl_attr_noreturn;
 extern ECL_API void FEtype_error_vector(cl_object x) ecl_attr_noreturn;
 extern ECL_API void FEcircular_list(cl_object x) ecl_attr_noreturn;
-extern ECL_API void FEtype_error_index(cl_object seq, cl_object ndx) ecl_attr_noreturn;
+extern ECL_API void FEtype_error_index(cl_object seq, cl_fixnum ndx) ecl_attr_noreturn;
 extern ECL_API void FEtype_error_array(cl_object x) ecl_attr_noreturn;
 extern ECL_API void FEdivision_by_zero(cl_object x, cl_object y) ecl_attr_noreturn;
 extern ECL_API cl_object ecl_type_error(cl_object function, const char *place, cl_object o, cl_object type);