Undetected escaping capability when using first class functions about effekt HOT 2 CLOSED

Thanks for reporting! This is a soundness bug with region inference on continuations. Instead of using escape on the region, we need to use the lambda passed to handle2 as the current region. This might be overly restrictive in some cases, but would be along the lines of our current region approximation and would prevent this source of unsoundness.

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This really was an oversight on my sight, as can be seen in the branch fixing it. Lambdas (that is, fun() { ... }) did introduce a new region, but anonymous block arguments (like in handle2 { ... }) did not. This is clearly wrong as illustrated by your example.

from effekt.