stack --stack-yaml x.yaml config set resolver nightly has no effect

[sjakobi]

~/s/store (intmap.size|…) $ cat intmap.size.yaml 
resolver: lts-7.18
packages:
- .
- store-core
- location: deps/weigh
  extra-dep: true
~/s/store (intmap.size|…) $ stack --stack-yaml intmap.size.yaml config set resolver nightly
Selected resolver: nightly-2017-03-01
Selected mirror https://s3.amazonaws.com/hackage.fpcomplete.com/                                 
Downloading timestamp                                                                            
No updates to your package list were found                                                       
Updating package index Hackage (mirrored at https://s3.amazonaws.com/hackage.fpcomplete.com/) ...The following package identifiers were not found in your indices: tasty-stats-0.2.0.2
~/s/store (intmap.size|…) $ cat intmap.size.yaml 
resolver: lts-7.18
packages:
- .
- store-core
- location: deps/weigh
  extra-dep: true
~/s/store (intmap.size|…) $ stack --version
Version 1.3.3, Git revision 8b0ab0bf687a225b2d724f743db50a20ddcc303c (dirty) (4613 commits) x86_64 hpack-0.17.0

[sjakobi]

Oh, I think I was simply seeing a side-effect of #3033 here.