Fixed duplicate dependency relationships

src/uml/class_diagram_model.h

@@ -117,6 +117,13 @@ struct class_relationship {
     std::string cardinality_source;
     std::string cardinality_destination;
     std::string label;
+
+    friend bool operator==(
+        const class_relationship &l, const class_relationship &r)
+    {
+        return l.type == r.type && l.destination == r.destination &&
+            l.label == r.label;
+    }
 };
 
 struct class_template {
@@ -140,6 +147,13 @@ public:
     std::vector<class_template> templates;
     std::string base_template_usr;
 
+    void add_relationship(class_relationship &&cr)
+    {
+        auto it = std::find(relationships.begin(), relationships.end(), cr);
+        if (it == relationships.end())
+            relationships.emplace_back(std::move(cr));
+    }
+
     std::string full_name(
         const std::vector<std::string> &using_namespaces) const
     {

src/uml/class_diagram_visitor.h

@@ -239,7 +239,7 @@ static enum CXChildVisitResult method_parameter_visitor(
 
                 assert(ctx->parent_class != nullptr);
 
-                ctx->parent_class->relationships.emplace_back(std::move(r));
+                ctx->parent_class->add_relationship(std::move(r));
             }
 
             ret = CXChildVisit_Continue;

tests/t00013/t00013.cc

@@ -33,6 +33,8 @@ public:
     // TODO: int get_b(const B &b) { return b.b; }
     int get_c(C c) { return c.c; }
     int get_d(D &&d) { return d.d; }
+    // Dependency relationship should be rendered only once
+    int get_d2(D &&d) { return d.d; }
 };
 }
 }