An often-stated disadvantage ofWhen Coalton is thatwritten theas embeddinga requirespart aof somewhat<code>.lisp</code> cumbersomefiles, it requires wrapping ofthe Coalton code in <code>coalton</code> or <code>coalton-toplevel</code> expressions,macros. This detractingdetracts from the directincremental anddevelopment interactive naturestyle of Common Lisp.<ref>https://news.ycombinator.com/item?id=35704441</ref>.
A more serious criticism is that Hindley-Milner type systems are unsound when mutation is allowed,<ref>{{cite andjournal Coalton—by|last1=Wright virtue|first1=Andrew of|title=Simple allowingimperative Lisppolymorphism code|journal=LISP toand beSymbolic embeddedComputation in|date=1995 its|volume=8 code—|pages=343–355 allows|doi=10.1007/BF01018828 mutation<ref>|url=https://githublink.springer.com/coalton-langarticle/coalton10.1007/issues/84BF01018828 |access-date=10 August 2025}}</ref>., Theand Coalton authors accept this shortcoming as a trade-off for the practical advantages that this brings, allowingallows mutation. isSeveral partfixes ofto the Commontype Lispinference culturealgorithm andhave mostbeen developers know how to safely deal with itproposed.<ref>https://github.com/coalton-lang/coalton/issues/84</ref>
