Hi,

The GHC manual says that if you pass -cpp to GHC, it runs the C preprocessor, "cpp" on your code before compilation (http://www.haskell.org/ghc/docs/latest/html/users_guide/options-phases.html#c-pre-processor).  But why, in that case, does stringize not seem to work when the -cpp flag is given?

In my example, test.hs is using the C preprocessor with a simple macro to trace functions with their name.  Running GHC with -cpp gives an error, but if I run cpp on the file directly then feed it to GHC, I get no error:

=====
$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 6.10.3


$ cat test.hs
import Debug.Trace

#define TR(f) (trace #f f)

main :: IO ()
main = TR(putStrLn) "Hello!"


$ ghc -cpp --make test.hs
[1 of 1] Compiling Main             ( test.hs, test.o )

test.hs:6:14: Not in scope: `#'


$ cpp test.hs
# 1 "test.hs"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "test.hs"
import Debug.Trace



main :: IO ()
main = (trace "putStrLn" putStrLn) "Hello!"


$ cpp test.hs > test-cpp.hs


$ ghc -cpp --make test-cpp.hs
[1 of 1] Compiling Main             ( test-cpp.hs, test-cpp.o )
Linking test-cpp ...


$ ./test-cpp
putStrLn
Hello!


=====

What am I missing?

Thanks,

Neil.