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author | Eric Seidel <gridaphobe@gmail.com> | 2015-09-02 10:22:01 +0200 |
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committer | Ben Gamari <ben@smart-cactus.org> | 2015-09-02 13:21:43 +0200 |
commit | 6740d70d95cb81cea3859ff847afc61ec439db4f (patch) | |
tree | 08199080ae5e55aafa1ff05cffd929039d3345bf /libraries/base/GHC/Exception.hs-boot | |
parent | ad26c54b86a868567d324d5de6fd0b4c2ed28022 (diff) | |
download | haskell-6740d70d95cb81cea3859ff847afc61ec439db4f.tar.gz |
Use IP based CallStack in error and undefined
This patch modifies `error`, `undefined`, and `assertError` to use
implicit call-stacks to provide better error messages to users.
There are a few knock-on effects:
- `GHC.Classes.IP` is now wired-in so it can be used in the wired-in
types for `error` and `undefined`.
- `TysPrim.tyVarList` has been replaced with a new function
`TysPrim.mkTemplateTyVars`. `tyVarList` made it easy to introduce
subtle bugs when you need tyvars of different kinds. The naive
```
tv1 = head $ tyVarList kind1
tv2 = head $ tyVarList kind2
```
would result in `tv1` and `tv2` sharing a `Unique`, thus substitutions
would be applied incorrectly, treating `tv1` and `tv2` as the same
tyvar. `mkTemplateTyVars` avoids this pitfall by taking a list of kinds
and producing a single tyvar of each kind.
- The types `GHC.SrcLoc.SrcLoc` and `GHC.Stack.CallStack` now live in
ghc-prim.
- The type `GHC.Exception.ErrorCall` has a new constructor
`ErrorCallWithLocation` that takes two `String`s instead of one, the
2nd one being arbitrary metadata about the error (but usually the
call-stack). A bi-directional pattern synonym `ErrorCall` continues to
provide the old API.
Updates Cabal, array, and haddock submodules.
Reviewers: nh2, goldfire, simonpj, hvr, rwbarton, austin, bgamari
Reviewed By: simonpj
Subscribers: rwbarton, rodlogic, goldfire, maoe, simonmar, carter,
liyang, bgamari, thomie
Differential Revision: https://phabricator.haskell.org/D861
GHC Trac Issues: #5273
Diffstat (limited to 'libraries/base/GHC/Exception.hs-boot')
-rw-r--r-- | libraries/base/GHC/Exception.hs-boot | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/libraries/base/GHC/Exception.hs-boot b/libraries/base/GHC/Exception.hs-boot index aa19897363..594f2665e8 100644 --- a/libraries/base/GHC/Exception.hs-boot +++ b/libraries/base/GHC/Exception.hs-boot @@ -25,10 +25,13 @@ to get a visibly-bottom value. -} module GHC.Exception ( SomeException, errorCallException, + errorCallWithCallStackException, divZeroException, overflowException, ratioZeroDenomException ) where -import GHC.Types( Char ) +import GHC.Types( Char, CallStack ) data SomeException divZeroException, overflowException, ratioZeroDenomException :: SomeException + errorCallException :: [Char] -> SomeException +errorCallWithCallStackException :: [Char] -> CallStack -> SomeException |