Update compiler

compiler/compiler.go

@@ -88,7 +88,7 @@ func (this *Compiler) AnalyzeModule (
 			newNickname, ok := dependency.Address.Nickname()
 			if !ok {
 				return uuid.UUID { }, ferrors.Errorf (
-					dependency.Position,
+					dependency.Position(),
 					"cannot generate nickname for %v, " +
 					"please add one after the address",
 					dependency.Address)
@@ -97,9 +97,9 @@ func (this *Compiler) AnalyzeModule (
 		}
 		if previous, exists := dependencies[nickname]; exists {
 			return uuid.UUID { }, ferrors.Errorf (
-				dependency.Position,
+				dependency.Position(),
 				"unit with nickname %v already listed at %v",
-				nickname, previous.Position)
+				nickname, previous.Position())
 		}
 		dependencies[nickname] = dependency
 	}