[Haskell] Blocked STM & GC question

If I have a thread that's blocked on an STM retry or TChan read, and none of its TVars are referenced elsewhere, will it get stopped and garbage-collected? I have in mind a pump thread that eternally reads off a TChan and pushes the result to some function. If the TChan is forgotten elsewhere, will the permanently blocked thread still sit around using up some small amount of memory, or will it be reaped by the garbage collector? -- Ashley Yakeley Seattle WA