proto-tt
It's a type checker for a simple dependently typed language. The type checking procedure is very similar to that of [1]: it's bidirectional and NbE-based, so we have raw terms and values, but since we're in a dependently typed setting, there are also typed terms indexed by values that represent types. E.g. typed Π-types are
data _⊢_ {n} (Γ : Con n) : Value n -> Set where
πᵗ : (σₜ : Γ ⊢ typeᵛ) -> Γ ▻ eval σₜ ⊢ typeᵛ -> Γ ⊢ typeᵛ
...
That example demonstrates that evaluation is defined on typed terms, which is a great source of confidence that type checking terminates, because there is no evaluation defined on raw terms.
Type checking returns either a (rudimentary) error or a typed term, hence the type system is Church-like and all typing rules are just constructors of _⊢_. Unlike in [1] binders in Value have Kripke semantics, e.g.
data Value n where
piᵛ : Value n -> Kripke n -> Value n
lamᵛ : Kripke n -> Value n
...
where Kripke n = ∀ {m} -> n ⊑ m -> Value m -> Value m.
There is one another constructor of Term: pure. It's used to store typed terms in raw terms to prevent retypechecking.
The Cubes repo is directly based upon this one.
References
[1] "Simply Easy! An Implementation of a Dependently Typed Lambda Calculus", Andres Löh, Conor McBride, Wouter Swierstra.