Infer rho-types instead of sigma-types in guard BindStmts and TransStmts

In #17343 we saw that we didn't handle the pattern guard `!_ <-
undefined` correctly: The `undefined` was never evaluated. Indeed,
elaboration failed to insert the invisible type aruments to `undefined`.
So `undefined` was trivially a normal-form and in turn never entered.

The problem is that we used to infer a sigma-type for the RHS of the
guard, the leading qualifiers of which will never be useful in a pattern
match situation. Hence we infer a rho-type now.

Fixes #17343.
21 jobs for master in 241 minutes and 23 seconds (queued for 24 seconds)
Status Job ID Name Coverage
  Lint
passed #179687
lint
lint-linters

00:00:20

passed #179690
lint
lint-submods-branch

00:00:23

passed #179688
lint
lint-testsuite

00:00:23

passed #179689
lint
typecheck-testsuite

00:00:21

 
  Quick Build
passed #179691
x86_64-linux
hadrian-ghc-in-ghci

00:17:22

 
  Build
passed #179694
x86_64-linux
release-x86_64-linux-deb9-dwarf

02:09:50

failed #179693
x86_64-linux
validate-x86_64-linux-deb9-debug

02:06:17

passed #179692
x86_64-linux
validate-x86_64-linux-deb9-hadrian

03:42:46

 
  Full Build
skipped #179696
aarch64-linux allowed to fail
validate-aarch64-linux-deb9
skipped #179697
x86_64-linux
validate-i386-linux-deb9
skipped #179695
x86_64-darwin
validate-x86_64-darwin
skipped #179698
x86_64-linux
validate-x86_64-linux-deb9-integer-simple
skipped #179699
x86_64-linux
validate-x86_64-linux-deb9-unreg
skipped #179700
x86_64-linux
validate-x86_64-linux-fedora27
skipped #179702
x86_64-windows allowed to fail
validate-x86_64-windows
skipped #179701
x86_64-windows allowed to fail
validate-x86_64-windows-hadrian
 
  Cleanup
passed #179703
x86_64-darwin
cleanup-darwin

00:00:05

 
  Packaging
skipped #179704
x86_64-linux allowed to fail
doc-tarball
 
  Testing
skipped #179705
x86_64-linux allowed to fail manual
hackage
skipped #179706
x86_64-linux
perf-nofib
 
  Deploy
skipped #179707
x86_64-linux allowed to fail
pages
 
Name Stage Failure
failed
validate-x86_64-linux-deb9-debug Build
$ cp -Rf $HOME/.cabal cabal-cache
Uploading artifacts...
ghc-*.tar.xz: found 1 matching files
junit.xml: found 1 matching files

Uploading artifacts to coordinator... ok
id=179693 responseStatus=201 Created token=U1nWEd6D
Uploading artifacts...
junit.xml: found 1 matching files

Uploading artifacts to coordinator... ok
id=179693 responseStatus=201 Created token=U1nWEd6D
ERROR: Job failed: exit code 1