From 045d9e7117b0df2ba5dd0683f0d6c7ff10972ba6 Mon Sep 17 00:00:00 2001
From: Maciej Suminski <maciej.suminski@cern.ch>
Date: Fri, 12 Feb 2016 15:17:03 +0100
Subject: [PATCH] vhdlpp: Improved type matching rules.

---
 vhdlpp/expression_elaborate.cc | 4 +++-
 vhdlpp/vtype.h                 | 3 +++
 vhdlpp/vtype_match.cc          | 7 +++++++
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/vhdlpp/expression_elaborate.cc b/vhdlpp/expression_elaborate.cc
index fa6a16841..e11a5e328 100644
--- a/vhdlpp/expression_elaborate.cc
+++ b/vhdlpp/expression_elaborate.cc
@@ -350,8 +350,10 @@ const VType* ExpBinary::probe_type(Entity*ent, ScopeBase*scope) const
       if (t2 == 0)
 	    return t1;
 
-      if (t1 == t2)
+      if (t1->type_match(t2))
 	    return t1;
+      if (t2->type_match(t1))
+	    return t2;
 
       if (const VType*tb = resolve_operand_types_(t1, t2))
 	    return tb;
diff --git a/vhdlpp/vtype.h b/vhdlpp/vtype.h
index fc1d52c0e..89b794a13 100644
--- a/vhdlpp/vtype.h
+++ b/vhdlpp/vtype.h
@@ -295,6 +295,9 @@ class VTypeRangeConst : public VTypeRange {
           return new VTypeRangeConst(base_type()->clone(), start_, end_);
       }
 
+      int64_t start() const { return start_; }
+      int64_t end() const { return end_; }
+
       void write_to_stream(std::ostream&fd) const;
 
     private:
diff --git a/vhdlpp/vtype_match.cc b/vhdlpp/vtype_match.cc
index 459217879..3ceb4b231 100644
--- a/vhdlpp/vtype_match.cc
+++ b/vhdlpp/vtype_match.cc
@@ -53,6 +53,13 @@ bool VTypePrimitive::type_match(const VType*that) const
               (that_type == NATURAL || that_type == INTEGER));
       }
 
+      if(const VTypeRangeConst*range = dynamic_cast<const VTypeRangeConst*>(that)) {
+           if (type_ == INTEGER)
+               return true;
+           if (type_ == NATURAL && range->start() >= 0 && range->end() >= 0)
+               return true;
+      }
+
       return false;
 }