Table of Contents
If you still have a problem after consulting this section, then you may have found a bug—please report it! See Section 1.3, “Reporting bugs in GHC” for details on how to report a bug and a list of things we'd like to know about your bug. If in doubt, send a report—we love mail from irate users :-!
(Section 13.1, “Haskell 98 vs. Glasgow Haskell: language non-compliance ”, which describes Glasgow Haskell's shortcomings vs. the Haskell language definition, may also be of interest.)
These events are always bugs in the GHC system—please report them.
If you think that GHC could have produced a better error message, please report it as a bug.
For example: “…warning: `Foo' declared `static' but never defined.” Unsightly, but shouldn't be a problem.
.hi interface files:
GHC is very sensitive about interface files. For
example, if it picks up a non-standard
Prelude.hi file, pretty terrible things
will happen. If you turn on
-XNoImplicitPrelude, the compiler will almost
surely die, unless you know what you are doing.
Furthermore, as sketched below, you may have big problems running programs compiled using unstable interfaces.
Unlikely :-) A useful be-more-paranoid option to give
to GHC is
-dcore-lint; this causes a
“lint” pass to check for errors (notably type
errors) after each Core-to-Core transformation pass. We run
-dcore-lint on all the time; it costs
about 5% in compile time.
If the linker complains about not finding
then something is inconsistent: you probably didn't compile
modules in the proper dependency order.
On this score, GHC usually does pretty well, especially if you “allow” it to be off by one or two. In the case of an instance or class declaration, the line number may only point you to the declaration, not to a specific method.
Please report line-number errors that you find particularly unhelpful.