This plugin allow implicitly add HasCallStack class to every top-level function for all module. Hence, we can to get completely continuous call stack.
- (implicitly) Import GHC.Stack for all modules.
- Add HasCallStack constraint for all top-level functions.
- Other supported syntaxes
-
whereclause
-
Requirement: (8.6 <= on GHC)
Synopsis
module Main where import Data.Maybe (fromJust) main :: IO () main = print f1 f1 :: Int f1 = f2 f2 :: Int f2 = f3 -- HsQualTy f3 :: HasCallStack => Int f3 = f4 0 -- HsQualTy f4 :: Show a => a -> Int f4 n = f5 (show n) 0 -- HsFunTy f5 :: String -> Int -> Int f5 _ _ = head f6 -- HsListTy f6 :: [Int] f6 = [fst f7] -- HsTupleTy f7 :: (Int, Int) f7 = (fromJust f8, fromJust f8) -- HsAppTy f8 :: Maybe Int f8 = Just f9 f9 :: Int f9 = f10 where f10 :: Int f10 = fError -- HsTyVar fError :: Int fError = error "fError"
This example get error:
$ cabal build
example/Main.hs:15:7: error:
Not in scope: type constructor or class ‘HasCallStack’
|
15 | f3 :: HasCallStack => Int
| ^^^^^^^^^^^^Yes, add import GHC.Stack to above example.
Fix and rebuild!
$ cabal run example -v0
example: fError
CallStack (from HasCallStack):
error, called at example/Main.hs:47:10 in main:MainHmm, it is not useful. But, you will to be happy when enable this plugin.
ghc-options:
-fplugin=StackTrace.Plugin$ cabal run example -v0 example: fError CallStack (from HasCallStack): error, called at example/Main.hs:47:10 in main:Main fError, called at example/Main.hs:43:11 in main:Main f10, called at example/Main.hs:40:6 in main:Main f9, called at example/Main.hs:37:11 in main:Main f8, called at example/Main.hs:33:16 in main:Main f7, called at example/Main.hs:29:11 in main:Main f6, called at example/Main.hs:25:15 in main:Main f5, called at example/Main.hs:21:8 in main:Main f4, called at example/Main.hs:17:6 in main:Main f3, called at example/Main.hs:13:6 in main:Main f2, called at example/Main.hs:10:6 in main:Main f1, called at example/Main.hs:7:14 in main:Main main, called at example/Main.hs:7:1 in main:Main
Great!!!