<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div id="yui_3_16_0_1_1439660789440_11909"><span id="yui_3_16_0_1_1439660789440_11972">Hi all,</span></div><div id="yui_3_16_0_1_1439660789440_11909"><span id="yui_3_16_0_1_1439660789440_11973">I'm trying to step through some ghc code.</span></div><div id="yui_3_16_0_1_1439660789440_11909" dir="ltr"><span id="yui_3_16_0_1_1439660789440_12026">I am trying to use pprTrace ( for the first time ) and I keep getting an error when I use it :</span></div><div id="yui_3_16_0_1_1439660789440_11909" dir="ltr"><span id="yui_3_16_0_1_1439660789440_12040">I've added it to the file ghc/Main.hs and the resulting code is this :</span></div><div id="yui_3_16_0_1_1439660789440_11909" dir="ltr"><span><br></span></div><div id="yui_3_16_0_1_1439660789440_11909" dir="ltr"><span id="yui_3_16_0_1_1439660789440_12076"> </span>let argv1' = map (mkGeneralLocated "on the commandline") argv1</div><div id="yui_3_16_0_1_1439660789440_11909" dir="ltr" class=""> (argv2, staticFlagWarnings) <- pprTrace "argv1 prime" (ppr argv1') $ parseStaticFlags argv1'</div><div id="yui_3_16_0_1_1439660789440_11909" dir="ltr" class=""><br></div><div id="yui_3_16_0_1_1439660789440_11909" dir="ltr" class="">I want to examine the value of argv1'. </div><div id="yui_3_16_0_1_1439660789440_11909" dir="ltr" class="">After my modification, I go into the ghc/ folder and run : 'make'</div><div id="yui_3_16_0_1_1439660789440_11909" dir="ltr" class="">But doing this leads to an error when I try to run the program :</div><div id="yui_3_16_0_1_1439660789440_11909" dir="ltr" class=""><br></div><div id="yui_3_16_0_1_1439660789440_11909" dir="ltr" class=""> ghc-stage2: panic! (the 'impossible' happened)</div><div id="yui_3_16_0_1_1439660789440_11909" dir="ltr" class=""> (GHC version 7.11.20150810 for x86_64-unknown-linux):</div><div id="yui_3_16_0_1_1439660789440_11909" dir="ltr" class=""><span class="" style="white-space:pre-wrap;" id="yui_3_16_0_1_1439660789440_12187"> </span>Static flags have not been initialised!</div><div id="yui_3_16_0_1_1439660789440_11909" dir="ltr" class=""> Please call GHC.parseStaticFlags early enough.</div><div id="yui_3_16_0_1_1439660789440_11909" dir="ltr" class=""><br></div><div id="yui_3_16_0_1_1439660789440_11909" dir="ltr" class="">What am I doing wrong ?</div><div></div><div id="yui_3_16_0_1_1439660789440_11910"> </div><div class="signature" id="yui_3_16_0_1_1439660789440_11911">Omar Mefire, </div></div></body></html>