[cvs-nhc98] segfault-causing examples

Isaac Dupree isaacdupree at charter.net
Fri Mar 2 16:38:03 EST 2007


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main = do
 print "hello"
 print (True)
 print "bye"

compiling with my darcs-nhc98 on my computer and running, I get:

"hello"
Segmentation fault (core dumped)



Before trying that, I noticed that Integers had some problems...

module Main(main) where
main = do
 print "hello"
 if 2 > (1::Int) then print "SmartInt" else print "StupidInt"
 if 2 > (1::Integer) then print "SmartIntegerA" else print
            "StupidIntegerA"
 if 1 < (2::Integer) then print "SmartIntegerB" else print
            "StupidIntegerB"
 print (1::Int)
 print (1::Integer)
 print "bye"


My results, plus comments verified by other experiments:
"hello"
"SmartInt" --Ints are fine
"StupidIntegerA" --Integers are
"SmartIntegerB"  --not working right
1 --Ints are still fine
Segmentation fault (core dumped) --Instance Show Integer crashes the program

show (1::Integer) `seq` print "integ" --prints "integ" (shallow seq)
foldr seq () (show (1::Integer)) `seq` print "integ" --crashes (deep seq)


I suppose maybe I compiled nhc wrong, since I manually modified an "=="
to "=" in one file, and restarted its compilation several times, though
I can't see how those could cause these problems...

Isaac

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