Possible compile time regression in GHC 8

[Sreenidhi Nair]

Hello,

While compiling the `record` package with ghc-8 rc3 with `stack build`, the
memory usage went above 6gb and started trashing. But when `stack build
--fast` (-O0) was being used the package compiled with maximum memory at
1.8gb.

Also `stack build` works fine with ghc-7.10.3 with the build taking about
1.7gb. Attached is the stack file to reproduce the issue.

Steps to reproduce:
1. Create a new directory and put the attached stack.yaml there.
2. run `stack build` - this will thrash after some time
3. run `stack build --fast` - this will succeed
4. run `stack build --resolver=ghc-7.10.3` - this will succeed as well
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