X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fghci%2FInteractiveUI.hs;h=30f1de6d275d7d51c58217ffb34c085b7e6b550e;hb=a0b2691bb9116d06bc6a3a16b36388b477791224;hp=e7df1bd15674b61e6d995154d2412e2524c20bcb;hpb=5860730b73d2907a9b35eeb316e374ae5b267aee;p=ghc-hetmet.git

diff --git a/compiler/ghci/InteractiveUI.hs b/compiler/ghci/InteractiveUI.hs
index e7df1bd..30f1de6 100644
--- a/compiler/ghci/InteractiveUI.hs
+++ b/compiler/ghci/InteractiveUI.hs
@@ -54,6 +54,7 @@ import System.Posix hiding (getEnv)
 #else
 import GHC.ConsoleHandler ( flushConsole )
 import qualified System.Win32
+import System.FilePath
 #endif
 
 #ifdef USE_READLINE
@@ -2138,9 +2139,23 @@ listCmd :: String -> GHCi ()
 listCmd "" = do
    mb_span <- getCurrentBreakSpan
    case mb_span of
-      Nothing  -> printForUser $ text "not stopped at a breakpoint; nothing to list"
-      Just span | GHC.isGoodSrcSpan span -> io $ listAround span True
-                | otherwise              -> printForUser $ text "unable to list source for" <+> ppr span
+      Nothing ->
+          printForUser $ text "Not stopped at a breakpoint; nothing to list"
+      Just span
+       | GHC.isGoodSrcSpan span -> io $ listAround span True
+       | otherwise ->
+          do s <- getSession
+             resumes <- io $ GHC.getResumeContext s
+             case resumes of
+                 [] -> panic "No resumes"
+                 (r:_) ->
+                     do let traceIt = case GHC.resumeHistory r of
+                                      [] -> text "rerunning with :trace,"
+                                      _ -> empty
+                            doWhat = traceIt <+> text ":back then :list"
+                        printForUser (text "Unable to list source for" <+>
+                                      ppr span
+                                   $$ text "Try" <+> doWhat)
 listCmd str = list2 (words str)
 
 list2 :: [String] -> GHCi ()