HAHA is a tool that helps in teaching and learning Hoare logic. It is targeted at an introductory course on software verification. We present a set of new features of the HAHA verification environment that exploit Coq. These features are (1) generation of verification conditions in Coq so that they can be explored and proved interactively and (2) compilation of HAHA programs into CompCert certified compilation tool-chain. With the interactive Coq proving support we obtain an interesting

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... ality that makes it possible to carefully examine step-by-step verification conditions and systematically discover flaws in their formulation. As a result Coq back-end serves as a kind of specification debugger.