-- # Shape coercions -- The Futhark type checker is not very smart, and in some cases is -- very conservative in how it tracks the sizes of arrays. For -- example: def A = [1,2,3] ++ [4,5,6] -- As far as the type checker is concerned, `A` has a completely -- unknown size. Using a *shape coercion* we can change the size to be -- what we expect: def B = [1,2,3] ++ [4,5,6] :> [6]i32 -- Shape coercions are checked dynamically, and the program will fail -- at run-time if the actual shape does not match the expected shape. -- The rank or element type of the array may not change - only the -- specific dimensions. -- # See also -- -- [Complex ranges](complex-ranges.html)