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+A type dependency cycle has been encountered.
+
+Erroneous code example:
+
+```compile_fail,E0391
+trait FirstTrait : SecondTrait {
+
+}
+
+trait SecondTrait : FirstTrait {
+
+}
+```
+
+The previous example contains a circular dependency between two traits:
+`FirstTrait` depends on `SecondTrait` which itself depends on `FirstTrait`.