Avoid QuickCheck for properties without free variables#237
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Avoid QuickCheck for properties without free variables#237
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Properties that have no free variables and have type `Bool` can be checked to be `True` without using QuickCheck. Properties with free variables need QuickCheck. Some properties may not have free variables but if the type is not `Bool` we use QuickCheck on the assumption that they are of some other `Test.QuickCheck.Testable` instance.
Author
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Sorry, that failing test case got lost amongst noise related to cabal-v2 and GHC-8.6.5 on my local machine. |
In this case with a single use it seems more appropriate to `fmap` rather than CPP the import.
Collaborator
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Hmm. I can appreciate this as an optimisation, but the UX worries me a shade. At the moment, the rule is simple: if you use |
Owner
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If somebody is willing to |
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Properties that have no free variables and have type
Boolcan be checkedto be
Truewithout using QuickCheck. Properties with free variables needQuickCheck. Some properties may not have free variables but if the type
is not
Boolwe use QuickCheck on the assumption that they are of someother
Test.QuickCheck.Testableinstance.The purpose of this pull request is to be able to benefit from the
prop>syntax for simple properties without pulling in QuickCheck as a dependency.An example in the wild:
Can be clearer (IMO) and more concisely written as:
(I will note that even when QuickCheck is not used
prop>will be slower than>>>due to calling the repl twice.)