shebang + literate haskell causes line numbering skew

Noticed on doctest's Setup.lhs file. Minimal example:

#!/usr/bin/env runhaskell
> main = return ()

$ inplace/bin/ghc-stage2 -fforce-recomp -Wall Setup
[1 of 1] Compiling Main             ( Setup.lhs, Setup.o )

Setup.lhs:1:3: warning: [-Wmissing-signatures]
    Top-level binding with no type signature: main :: IO ()
  |
1 | #!/usr/bin/env runhaskell
  |   ^^^^

Notice how it points 4 characters a line before main.

Trac metadata

Trac field	Value
Version	8.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	low
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture

changed weight to 3

added Tbug Trac import labels

https://phabricator.haskell.org/D3333 should fix this.

Trac metadata

Trac field	Value
Differential revisions	- → D3333

mentioned in commit c77b7670

closed

changed milestone to %8.2.1

Merged to ghc-8.2 as bd3c648d.

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedFixed

added error messages label

added Plow label