diff --git a/src/ltlparse/ltlparse.yy b/src/ltlparse/ltlparse.yy
index 15000e7eb..b02b63668 100644
--- a/src/ltlparse/ltlparse.yy
+++ b/src/ltlparse/ltlparse.yy
@@ -376,12 +376,31 @@ rationalexp: booleanatom
 	    | rationalexp OP_FUSION error
               { missing_right_binop($$, $1, @2, "fusion operator"); }
 	    | rationalexp starargs
-	      { $$ = bunop::instance(bunop::Star, $1, $2.min, $2.max); }
+	      {
+		if ($2.max < $2.min)
+		  {
+		    error_list.push_back(parse_error(@2, "reversed range"));
+		    std::swap($2.max, $2.min);
+		  }
+		$$ = bunop::instance(bunop::Star, $1, $2.min, $2.max);
+	      }
 	    | starargs
-	      { $$ = bunop::instance(bunop::Star, constant::true_instance(),
-                                    $1.min, $1.max); }
+	      {
+		if ($1.max < $1.min)
+		  {
+		    error_list.push_back(parse_error(@1, "reversed range"));
+		    std::swap($1.max, $1.min);
+		  }
+		$$ = bunop::instance(bunop::Star, constant::true_instance(),
+				     $1.min, $1.max);
+	      }
 	    | rationalexp equalargs
 	      {
+		if ($2.max < $2.min)
+		  {
+		    error_list.push_back(parse_error(@2, "reversed range"));
+		    std::swap($2.max, $2.min);
+		  }
 		if ($1->is_boolean())
 		  {
 		    $$ = bunop::instance(bunop::Equal, $1, $2.min, $2.max);
@@ -399,6 +418,11 @@ rationalexp: booleanatom
 	      }
 	    | rationalexp gotoargs
 	      {
+		if ($2.max < $2.min)
+		  {
+		    error_list.push_back(parse_error(@2, "reversed range"));
+		    std::swap($2.max, $2.min);
+		  }
 		if ($1->is_boolean())
 		  {
 		    $$ = bunop::instance(bunop::Goto, $1, $2.min, $2.max);
diff --git a/src/ltltest/parseerr.test b/src/ltltest/parseerr.test
index 20d0c2714..185453e7b 100755
--- a/src/ltltest/parseerr.test
+++ b/src/ltltest/parseerr.test
@@ -1,6 +1,6 @@
 #! /bin/sh
-# Copyright (C) 2009, 2010 Laboratoire de Recherche et Développement
-# de l'Epita (LRDE).
+# Copyright (C) 2009, 2010, 2011 Laboratoire de Recherche et
+# Développement de l'Epita (LRDE).
 # Copyright (C) 2003, 2004 Laboratoire d'Informatique de Paris 6 (LIP6),
 # département Systèmes Répartis Coopératifs (SRC), Université Pierre
 # et Marie Curie.
@@ -85,6 +85,13 @@ run 0 ../equals -E 'a & (a + b c' 'a & (0)'
 run 0 ../equals -E 'a & (+' 'a & (0)'
 run 0 ../equals -E 'a & ('  'a & (0)'
 
+# Invalid ranges
+run 0 ../equals -E '{a[*8..1];b}' '{a[*1..8];b}'
+run 0 ../equals -E '{a[=8..1];b}' '{a[=1..8];b}'
+run 0 ../equals -E '{a[->8..1];b}' '{a[->1..8];b}'
+run 0 ../equals -E '{a[->..0];b}' '{a[->0..1];b}'
+
+
 check 'a - b' 'AP(a)' '>>> a - b
       ^
 syntax error, unexpected $undefined