-O -g breaks string literals

With foo.hs:

main = print (4, "foo")

Compile it and run it like:

% ghc-stage2 -O -g foo.hs
% ./foo
(4,"\CANq@")

Note that the content of the string literal is broken, although the length is preserved.

With -dcore-lint, the following error is produced:

*** Core Lint errors : in result of Simplifier ***
<no location info>: warning:
    [RHS of ww2_s3hG :: Addr#]
    Recursive or top-level binder has strict demand info: ww2_s3hG
    Binder's demand info: <L,U>

The offending binding is:

ww2_s3hG :: Addr#
[LclId,
 Unf=Unf{Src=<vanilla>, TopLvl=False, Value=True, ConLike=True,
         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 20 0}]
ww2_s3hG = src<foo.hs:1:18-22> "foo"#

Happens with ghc 8.4.1-rc1 and with HEAD (df2c3b33).

Trac metadata

Trac field	Value
Version	8.5
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture