-in the right argument. (As with the array function, the indices in the
-association list must be unique for the updated elements to be
-defined.) For example, if m is a 1-origin, n by n matrix, then
-@m\/\/[((i,i), 0) | i \<- [1..n]]@ is the same matrix, except with the
-diagonal zeroed.
+in the right argument. For example, if m is a 1-origin, n by n matrix,
+then @m\/\/[((i,i), 0) | i \<- [1..n]]@ is the same matrix, except with
+the diagonal zeroed.
+
+As with the 'array' function, if any two associations in the list have
+the same index, the value at that index is implementation-dependent.
+(In GHC, the last value specified for that index is used.
+Other implementations will also do this for unboxed arrays, but Haskell
+98 requires that for 'Array' the value at such indices is bottom.)