Wrong line number reported with CPP and line beginning with #

If I compile

{-# LANGUAGE CPP #-}

module Bug where

{-
  # hi there!
-}

*

I'm told of a parse error for the * on line 10. But that * is line 9!

The problem is that, with CPP on, the line number counter gets confused if a line begins with a #, perhaps after whitespace.

I actually hit this and was confused in real code.

Trac metadata

Trac field	Value
Version	7.10.1-rc2
Type	Bug
TypeOfFailure	OtherFailure
Priority	low
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system	Unknown/Multiple
Architecture

mentioned in issue #6132

changed weight to 3

added Tbug Trac import labels

Looks like a bug in clang's C preprocessor (I get the expected behavior with gcc's):

rwbarton@morphism:/tmp$ clang -E -x assembler-with-cpp Bug.hs
# 1 "Bug.hs"
# 1 "<built-in>" 1
# 1 "Bug.hs" 2
 {-# LANGUAGE CPP #-}

 module Bug where

 {-
   # hi there!

 -}

 *

Why did it add a blank line after # hi there!? (Same output regardless of -traditional and/or -undef.)

added cpp label

mentioned in issue #10628 (closed)

Trac metadata

Trac field	Value
Operating system	Unknown/Multiple → MacOS X

added clang label and removed cpp label

added Plow label