Apply a missing substitution in mkEtaWW (#16979)

The `mkEtaWW` case for newtypes forgot to apply the substitution to
the newtype coercion, resulting in the Core Lint errors observed
in #16979. Easily fixed.

Fixes #16979.

Co-authored-by: Ryan Scott <ryan.gl.scott@gmail.com>
(cherry picked from commit 2829f6da)
18 jobs for !1558 with wip/backports in 422 minutes and 39 seconds (queued for 8 seconds)
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Status Job ID Name Coverage
  Lint
failed #140053
lint allowed to fail
ghc-linters

00:00:21

passed #140054
lint
lint-submods-mr

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  Build
failed #140057
x86_64-linux allowed to fail
release-x86_64-linux-deb9-dwarf

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x86_64-linux
validate-x86_64-linux-deb8-hadrian

03:37:33

passed #140056
x86_64-linux
validate-x86_64-linux-deb9-debug

01:03:36

 
  Full Build
failed #140059
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validate-aarch64-linux-deb9

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passed #140060
x86_64-linux
validate-i386-linux-deb9

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x86_64-darwin
validate-x86_64-darwin

00:58:56

passed #140061
x86_64-linux
validate-x86_64-linux-deb9

01:46:00

failed #140063
x86_64-linux allowed to fail
validate-x86_64-linux-deb9-integer-simple

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x86_64-linux
validate-x86_64-linux-deb9-llvm

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x86_64-linux
validate-x86_64-linux-deb9-unreg

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x86_64-linux
validate-x86_64-linux-fedora27

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failed #140067
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validate-x86_64-windows

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validate-x86_64-windows-hadrian

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  Cleanup
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cleanup-darwin

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  Hackage
manual #140070
x86_64-linux allowed to fail manual
hackage
 
Name Stage Failure
failed
ghc-linters Lint
commit 2c9d37ba26c390bca2cb2f7835571b7cc4fa17e8 has whitespace linter issues:

*ERROR* compiler/typecheck/TcRnTypes.hs:1023: introduces trailing whitespace
> "set 'RunSplice' when renaming or typechecking the splice, where 'Splice', "

Validation FAILED for 2c9d37ba26c390bca2cb2f7835571b7cc4fa17e8
=====================================================================================
Validation FAILED because at least one commit had linter errors!
ERROR: Job failed: exit code 1
failed
validate-aarch64-linux-deb9 Full Build
$ cp -Rf $HOME/.cabal cabal-cache
Uploading artifacts...
WARNING: ghc-*.tar.xz: no matching files
WARNING: junit.xml: no matching files
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Uploading artifacts...
WARNING: junit.xml: no matching files
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ERROR: Job failed: exit code 1
failed
validate-x86_64-windows-hadrian Full Build
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Ended : Saturday, August 10, 2019 12:37:12 AM

Uploading artifacts...
Runtime platform arch=amd64 os=windows pid=7272 revision=1f513601 version=11.10.1
WARNING: ghc.tar.xz: no matching files
ERROR: No files to upload
ERROR: Job failed: exit status 1
failed
release-x86_64-linux-deb9-dwarf 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=140057 responseStatus=201 Created token=rUxN5fUz
Uploading artifacts...
junit.xml: found 1 matching files

Uploading artifacts to coordinator... ok
id=140057 responseStatus=201 Created token=rUxN5fUz
ERROR: Job failed: exit code 1
failed
validate-x86_64-windows Full Build
junit.xml: found 1 matching files                  
WARNING: Failed to load system CertPool:crypto/x509: system root pool is not available on Windows
Uploading artifacts to coordinator... ok
id=140067 responseStatus=201 Created token=RLrL87Ys
Uploading artifacts...
Runtime platform
arch=amd64 os=windows pid=6452 revision=1f513601 version=11.10.1
junit.xml: found 1 matching files

WARNING: Failed to load system CertPool:crypto/x509: system root pool is not available on Windows
Uploading artifacts to coordinator... ok
id=140067 responseStatus=201 Created token=RLrL87Ys
ERROR: Job failed: exit status 2
failed
validate-x86_64-linux-deb9-integer-simple Full Build
make[1]: *** Waiting for unfinished jobs....
make: *** [all] Error 2
Makefile:123: recipe for target 'all' failed
Running after script...
$ cp -Rf $HOME/.cabal cabal-cache
Uploading artifacts...
WARNING: junit.xml: no matching files
ERROR: No files to upload
ERROR: Job failed: exit code 1