anchor.diff:          // Preconditions
           checkInitialized "source" source
           checkInitialized "target" target
  +        // TODO : sourceIndex, targetIndex, count in-bounds
           
           notImpl "Vector.blit"
   
       //
       [<CompiledName("Collect")>]
  -    let collect (mapping : 'T -> 'U[]) (vector : vector<'T>) : vector<'U> =
  -        // Preconditions
  -        checkInitialized "vector" vector
  +    let collect (mapping : 'T -> vector<'U>) (vec : vector<'T>) : vector<'U> =
  +        // Preconditions
  +        checkInitialized "vec" vec
           
           notImpl "Vector.collect"
   
  
positive.code: 
      //
      [<CompiledName("TryPick")>]
      let tryPick (chooser : 'T -> 'U option) (vector : vector<'T>) : 'U option =
          // Preconditions
          checkInitialized "vector" vector
          
          notImpl "Vector.tryPick"
  
      //
      [<CompiledName("Pick")>]
      let pick (chooser : 'T -> 'U option) (vector : vector<'T>) : 'U =
          // Preconditions
          checkInitialized "vector" vector
          
          notImpl "Vector.pick"
  
      //
      [<CompiledName("Choose")>]
      let choose (chooser : 'T -> 'U option) (vector : vector<'T>) : vector<'U> =
          // Preconditions
          checkInitialized "vector" vector
          
          notImpl "Vector.choose"
  
  
negative.code:         // Create a shallow copy of the source array, then pass it to
          // the private Vector constructor and return the new Vector value.
          vector (Array.copy source)
  
      /// Creates a new Vector from the given array.
      /// This method is considered "unsafe" (and restricted to internal callers only)
      /// because it uses the given array directly instead of making a copy of it.
      static member internal UnsafeCreate (source : 'T[]) : vector<'T> =
          // Preconditions
          checkNonNull "source" source
  
          // Create a new vector directly from the source array.
          vector (source)
  
  
  /// Functional operators related to vectors (immutable arrays).
  