diff options
Diffstat (limited to 'libraries/base/GHC/Err.hs')
| -rw-r--r-- | libraries/base/GHC/Err.hs | 16 |
1 files changed, 6 insertions, 10 deletions
diff --git a/libraries/base/GHC/Err.hs b/libraries/base/GHC/Err.hs index 07d263bf7d..c3e21eeee2 100644 --- a/libraries/base/GHC/Err.hs +++ b/libraries/base/GHC/Err.hs @@ -54,16 +54,12 @@ errorWithoutStackTrace s = raise# (errorCallException s) -- a partial stack trace, containing the call-site of each function -- with a HasCallStack constraint. -- --- In base, however, the only functions that have such constraints are --- error and undefined, so the stack traces from partial functions in --- base will never contain a call-site in user code. Instead we'll --- usually just get the actual call to error. Base functions already --- have a good habit of providing detailed error messages, including the --- name of the offending partial function, so the partial stack-trace --- does not provide any extra information, just noise. Thus, we export --- the callstack-aware error, but within base we use the --- errorWithoutStackTrace variant for more hygienic error messages. - +-- In base, error and undefined were the only functions that had such +-- constraint. Errors like "Prelude.!!: negative index" are good, yet if the +-- code base contains dozens of !! applications (including dependencies, +-- which code is not as easily accessible), pinpointing the bad call is +-- where the stack trace would help. Therefore we annotate most calls to +-- error, so users have a chance to get a better idea. -- | A special case of 'error'. -- It is expected that compilers will recognize this and insert error |