Sometimes opening a new .hs file takes ages -- imports are processed at one per 3 seconds

[deepfire]

Sometimes opening a new .hs file takes ages -- imports are processed at the rate of one per several seconds.

GHC version: 7.10

I could provide an example of a module triggering this, but I doubt it's going to be helpful.

[DanielG]

Please do, test cases always help.

[DanielG]

I'm not sure what the elisp does now but maybe we can bulk query ghc-mod instead of invoking the executable multiple times. My thinking here being that the environment setup has become much slower than it used to be so each invocation has become a lot more costly which wasn't the case when the elisp was written.