Segfault if gallopingSearchLeftPBounds is used with too large u

[nh2]

This illegal use of gallopingSearchLeftPBounds segfaults in ghci 8.6.5:

import           Data.Vector.Algorithms.Search (binarySearchP, gallopingSearchLeftPBounds, binarySearch)
import qualified Data.Vector.Mutable as VM
import qualified Data.Vector as V

v <- V.thaw $ V.fromList [1,2,3]

gallopingSearchLeftPBounds (2 <) v 0 10

Note I give u = 10 when the maximum allowed values is 3 for the vector [1,2,3].

So it's expected that it fails.

However, a segfault is not expected, because I compile with default flags boundschecks = Enabled, and I the function doesn't have unsafe in the name or the docs, so I would expect a bounds check to happen.

[erikd]

What would you suggest as a solution?

After a rudimentary examination of the issue, one solution is:

• If the upper bound is greater than the length of the vector, simply return u
• If the lower bound is less than the length of the vector, simply return '`l'

Would that work?