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Description
When a lambda is in a context where effect checking is enabled -- e.g. the lambda is within a file that is effect-checked (see issue #293) or it is within a function that is annotated with effects - then the lambda should be effect checked and an effect should be part of its type.
I'm marking this as a bug (not an enhancement) because there is no way to get effects checked on a lambda without this, and the effect system is unsound for lambdas without this.