fixed side-effect in Go code

@@ -350,7 +350,7 @@ func (self Marking) Geq (other Marking) bool {
 //... a.Geq(b)
 //=== false
 
-func (self Marking) Iter (place string) (MsetIterator, *interface{}) {
+func (self Marking) Iter (place string) (MsetIterator, interface{}) {
 	mset, found := (*self.data)[place]
 	if found {
 		return mset.Iter()
@@ -359,7 +359,7 @@ func (self Marking) Iter (place string) (MsetIterator, *interface{}) {
 	}
 }
 
-func (self Marking) IterDup (place string) (MsetIterator, *interface{}) {
+func (self Marking) IterDup (place string) (MsetIterator, interface{}) {
 	mset, found := (*self.data)[place]
 	if found {
 		return mset.IterDup()

@@ -176,11 +176,11 @@ func (self Mset) Count (value interface{}) int {
 type MsetIterator struct {
 	done bool
 	ask chan bool
-	rep chan *interface{}
+	rep chan interface{}
 }
 
-func (self MsetIterator) Next() *interface{} {
-	var rep *interface{}
+func (self MsetIterator) Next() interface{} {
+	var rep interface{}
 	if self.done {
 		return nil
 	}
@@ -209,7 +209,7 @@ func (self Mset) iterate (it MsetIterator, dup bool) {
 				return
 			}
 			if <- it.ask {
-				it.rep <- &key
+				it.rep <- key
 			} else {
 				return
 			}
@@ -220,14 +220,14 @@ func (self Mset) iterate (it MsetIterator, dup bool) {
 	}
 }
 
-func (self Mset) Iter () (MsetIterator, *interface{}) {
-	it := MsetIterator{false, make(chan bool), make(chan *interface{})}
+func (self Mset) Iter () (MsetIterator, interface{}) {
+	it := MsetIterator{false, make(chan bool), make(chan interface{})}
 	go self.iterate(it, false)
 	return it, it.Next()
 }
 
-func (self Mset) IterDup () (MsetIterator, *interface{}) {
-	it := MsetIterator{false, make(chan bool), make(chan *interface{})}
+func (self Mset) IterDup () (MsetIterator, interface{}) {
+	it := MsetIterator{false, make(chan bool), make(chan interface{})}
 	go self.iterate(it, true)
 	return it, it.Next()
 }

@@ -147,7 +147,7 @@ class CodeGenerator (ast.CodeGenerator) :
         self.fill("for %s, %s := %s.Iter(%s); %s != nil; %s = %s.Next() {"
                   % (ivar, pvar, node.marking, S(node.place.name), pvar, pvar, ivar))
         with self.indent() :
-            self.fill("%s = (*%s).(%s)"
+            self.fill("%s = %s.(%s)"
                       % (node.variable, pvar, self.typedef[node.place.type]))
             self.fill("if ")
             self.visit(node.guard)
@@ -168,7 +168,7 @@ class CodeGenerator (ast.CodeGenerator) :
         self.fill("for %s, %s := %s.Iter(%s); %s != nil; %s = %s.Next() {"
                   % (ivar, pvar, node.marking, S(node.place.name), pvar, pvar, ivar))
         with self.indent() :
-            self.fill("%s = (*%s).(%s)"
+            self.fill("%s = %s.(%s)"
                       % (node.variable, pvar, self.typedef[node.place.type]))
         self.children_visit(node.body, True)
         self.fill("}")
@@ -190,7 +190,7 @@ class CodeGenerator (ast.CodeGenerator) :
             self.fill("for %s, %s := %s.Iter(); %s != nil; %s = %s.Next() {"
                       % (ivar, pvar, node.variable, pvar, pvar, ivar))
             with self.indent() :
-                self.fill("_, %s = (*%s).(%s)"
+                self.fill("_, %s = %s.(%s)"
                           % (bvar, pvar, self.typedef[node.place.type]))
                 self.fill("if ! %s { break }" % bvar)
             self.fill("}")