Defer Haskell type errors to runtime: new GHC 7.6 developers' flag

Re:Defer Haskell type errors to runtime: new GHC 7.6 develop... by olalonde on Saturday May 19, 2012 @02:20PM (#3996591)

Sorry for the stupid question but how is this even possible for a compiled language? Will the program simply crash without an error message?

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Re:Defer Haskell type errors to runtime: new GHC 7.6 develop... by gtani on Saturday May 19, 2012 @04:26PM (#3996969)

Perfectly valid question. This explains the practice in incremental dev or refactoring of using "undefined" in stub/placeholder functions to get the type signatures but not function bodies in:

http://www.fatvat.co.uk/2009/09/generating-text-in-haskell.h...

Also: 2 longish threads about this

http://www.reddit.com/r/programming/duplicates/tjeg3/haskell...

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Re:Defer Haskell type errors to runtime: new GHC 7.6 develop... by Chirono on Saturday May 19, 2012 @02:34PM (#3996629)

Instead of failing with an error at compile time, it will emit code that, if run, will fail with a 'type error' at run time.

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Re:Defer Haskell type errors to runtime: new GHC 7.6 develop... by strager on Saturday May 19, 2012 @02:35PM (#3996631)

In short, compiled type errors are replaced with `assert(0);` (which doesn't return).

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Re:Defer Haskell type errors to runtime: new GHC 7.6 develop... by IsTom on Saturday May 19, 2012 @02:31PM (#3996620)

It will simply crash with an error message.

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Re:Defer Haskell type errors to runtime: new GHC 7.6 develop... by ralfn on Saturday May 19, 2012 @09:02PM (#3997584)

Well, they just fix the error by replacing the offending code with code that emits a run-time type error.

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Re:Defer Haskell type errors to runtime: new GHC 7.6 develop... by olalonde on Sunday May 20, 2012 @03:27AM (#3998210)

Thanks, that explains it.

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