mysterious unwanted user goal being added to my new-install targets

Previously I was hacking on `grenade`, using `cabal v1-install`. Now i switch to an unrelated project, `et`, and `cabal new-install` fails mysteriously, trying and failing to install `grenade`.

claude@eiskaffee:~/code/code.mathr.co.uk/et$ cabal new-install et.cabal
Wrote tarball sdist to
/home/claude/code/code.mathr.co.uk/et/dist-newstyle/sdist/et-0.tar.gz
Resolving dependencies...
cabal: Could not resolve dependencies:
[__0] trying: containers-0.6.0.1/installed-0.6... (user goal)
[__1] next goal: grenade (user goal)
[__1] rejecting: grenade-0.1.0 (conflict:
containers==0.6.0.1/installed-0.6..., grenade => containers>=0.5 && <0.6)
[__1] fail (backjumping, conflict set: containers, grenade)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: containers, grenade

AFAIK `et` does not depend (even indirectly) upon `grenade`.

claude@eiskaffee:~/code/code.mathr.co.uk/et$ cabal new-install et.cabal -v3 | grep target
targets: array, base, binary, bytestring, containers, deepseq, directory, et, filepath, ghc, ghc-boot, ghc-boot-th, ghc-prim, ghci, grenade, hpc, integer-gmp, pretty, process, rts, template-haskell, terminfo, text, time, transformers, unix
ghc ==8.6.3 (user target)
bytestring ==0.10.8.2 (user target)
unix ==2.7.2.2 (user target)
base ==4.12.0.0 (user target)
time ==1.8.0.2 (user target)
hpc ==0.6.0.3 (user target)
filepath ==1.4.2.1 (user target)
process ==1.6.3.0 (user target)
array ==0.5.3.0 (user target)
integer-gmp ==1.0.2.0 (user target)
containers ==0.6.0.1 (user target)
ghc-boot ==8.6.3 (user target)
binary ==0.8.6.0 (user target)
ghc-prim ==0.5.3 (user target)
ghci ==8.6.3 (user target)
rts ==1.0 (user target)
terminfo ==0.4.1.2 (user target)
transformers ==0.5.5.0 (user target)
deepseq ==1.4.4.0 (user target)
ghc-boot-th ==8.6.3 (user target)
pretty ==1.1.3.6 (user target)
template-haskell ==2.14.0.0 (user target)
directory ==1.3.3.0 (user target)
text ==1.2.3.1 (user target)
grenade ==0.1.0 (user target)
grenade ==0.1.0 (user target)
et.et ==0 (user target)
[__6] rejecting: directory-1.3.3.1 (constraint from user target requires ==1.3.3.0)
[__7] rejecting: directory-1.3.3.1 (constraint from user target requires ==1.3.3.0)
[134] rejecting: containers-0.5.11.0, containers-0.5.10.2, containers-0.5.10.1, containers-0.5.9.2, containers-0.5.8.2, containers-0.5.7.1, containers-0.5.7.0, containers-0.5.6.3, containers-0.5.6.2, containers-0.5.6.1, containers-0.5.6.0, containers-0.5.5.1, containers-0.5.5.0, containers-0.5.4.0, containers-0.5.3.1, containers-0.5.3.0, containers-0.5.2.1, containers-0.5.2.0, containers-0.5.1.0, containers-0.5.0.0, containers-0.4.2.1, containers-0.4.2.0, containers-0.4.1.0, containers-0.4.0.0, containers-0.3.0.0, containers-0.2.0.1, containers-0.2.0.0, containers-0.1.0.1, containers-0.1.0.0, containers-0.5.9.1, containers-0.5.8.1 (constraint from user target requires ==0.6.0.1)
[_78] rejecting: containers-0.5.11.0, containers-0.5.10.2, containers-0.5.10.1, containers-0.5.9.2, containers-0.5.8.2, containers-0.5.7.1, containers-0.5.7.0, containers-0.5.6.3, containers-0.5.6.2, containers-0.5.6.1, containers-0.5.6.0, containers-0.5.5.1, containers-0.5.5.0, containers-0.5.4.0, containers-0.5.3.1, containers-0.5.3.0, containers-0.5.2.1, containers-0.5.2.0, containers-0.5.1.0, containers-0.5.0.0, containers-0.4.2.1, containers-0.4.2.0, containers-0.4.1.0, containers-0.4.0.0, containers-0.3.0.0, containers-0.2.0.1, containers-0.2.0.0, containers-0.1.0.1, containers-0.1.0.0, containers-0.5.9.1, containers-0.5.8.1 (constraint from user target requires ==0.6.0.1)
[_78] rejecting: containers~>rounded:hsc2hs:exe.containers-0.5.11.0 (constraint from user target requires ==0.6.0.1)
[_78] rejecting: containers-0.5.11.0, containers-0.5.10.2, containers-0.5.10.1, containers-0.5.9.2, containers-0.5.8.2, containers-0.5.7.1, containers-0.5.7.0, containers-0.5.6.3, containers-0.5.6.2, containers-0.5.6.1, containers-0.5.6.0, containers-0.5.5.1, containers-0.5.5.0, containers-0.5.4.0, containers-0.5.3.1, containers-0.5.3.0, containers-0.5.2.1, containers-0.5.2.0, containers-0.5.1.0, containers-0.5.0.0, containers-0.4.2.1, containers-0.4.2.0, containers-0.4.1.0, containers-0.4.0.0, containers-0.3.0.0, containers-0.2.0.1, containers-0.2.0.0, containers-0.1.0.1, containers-0.1.0.0, containers-0.5.9.1, containers-0.5.8.1 (constraint from user target requires ==0.6.0.1)
CallStack (from HasCallStack):
die', called at ./Distribution/Client/ProjectPlanning.hs:574:42 in main:Distribution.Client.ProjectPlanning
cabal: Could not resolve dependencies:
[__0] trying: containers-0.6.0.1/installed-0.6... (user goal)
[__1] next goal: grenade (user goal)
[__1] rejecting: grenade-0.1.0 (conflict:
containers==0.6.0.1/installed-0.6..., grenade => containers>=0.5 && <0.6)
[__1] fail (backjumping, conflict set: containers, grenade)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: containers (105), grenade (17)

`et.cabal` file at https://code.mathr.co.uk/et/blob/6e7517ec34b7693b10f8553f49a8c68b19f20dab:/et.cabal

I have tried to wipe all traces of `grenade` from `~/.cabal`, but have not quite succeeded:

claude@eiskaffee:~/.cabal$ grep -R grenade . | grep -v /logs/ | grep -v /doc/
Binary file ./packages/hackage.haskell.org/01-index.tar.idx matches
Binary file ./packages/hackage.haskell.org/00-index.tar matches
Binary file ./packages/hackage.haskell.org/01-index.tar matches
Binary file ./packages/hackage.haskell.org/01-index.cache matches
./packages/hackage.haskell.org/00-index.cache:pkg: grenade 0.1.0 b# 271065
Binary file ./bin/mirror matches
Binary file ./bin/nnirror matches
Binary file ./store/ghc-8.0.2/package.db/package.cache matches
Binary file ./store/ghc-8.2.2/package.db/package.cache matches
Binary file ./store/ghc-8.6.3/package.db/package.cache matches
Binary file ./store/ghc-8.4.4/package.db/package.cache matches

I am using `ghc-8.6.3`.

claude@eiskaffee:~$ cabal --version
cabal-install version 2.4.1.0
compiled using version 2.4.1.0 of the Cabal library