From ad519b85680a3493decad8731f74ae06f795a001 Mon Sep 17 00:00:00 2001
From: Alexandre Duret-Lutz <adl@lrde.epita.fr>
Date: Tue, 2 Mar 2010 12:44:46 +0100
Subject: [PATCH] Do not assume that concatenation cannot accept the empty
 word.

For instance "(a+#e);(b+#e);(c*)" does.

* src/ltlvisit/consterm.cc: Fix handling of Concat operator.
* src/ltltest/consterm.test: Add more tests.
---
 src/ltltest/consterm.test |  3 +++
 src/ltlvisit/consterm.cc  | 10 +---------
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/src/ltltest/consterm.test b/src/ltltest/consterm.test
index 9bab7b9b0..2810a9d13 100755
--- a/src/ltltest/consterm.test
+++ b/src/ltltest/consterm.test
@@ -37,3 +37,6 @@ run 1 ../consterm '((a ; b) + #e)'
 run 0 ../consterm '((a ; b) + #e) & e'
 run 1 ../consterm '((a ; b) + #e) & #e'
 run 1 ../consterm '((a ; b) + #e) & (a* + b)'
+run 1 ../consterm '(a + #e);(b + #e);(c + #e)'
+run 0 ../consterm '(a + #e);(b + e);(c + #e)'
+run 1 ../consterm '(a + #e);(b + e)*;(c + #e)'
diff --git a/src/ltlvisit/consterm.cc b/src/ltlvisit/consterm.cc
index 44fa95b0f..74b93e4e3 100644
--- a/src/ltlvisit/consterm.cc
+++ b/src/ltlvisit/consterm.cc
@@ -97,12 +97,6 @@ namespace spot
 	void
 	visit(const multop* mo)
 	{
-	  if (mo->op() == multop::Concat)
-	    {
-	      result_ = false;
-	      return;
-	    }
-
 	  unsigned max = mo->size();
 	  // This sets the initial value of result_.
 	  mo->nth(0)->accept(*this);
@@ -119,13 +113,11 @@ namespace spot
 		    return;
 		  break;
 		case multop::And:
+		case multop::Concat:
 		  result_ &= r;
 		  if (!result_)
 		    return;
 		  break;
-		case multop::Concat:
-		  assert(!"unreachable code");
-		  break;
 		}
 	    }
 	}