0.25.1

Added

• Arbitrary expressions of type i64 are now allowed as sizes. Work
  by Lubin Bailly.

• New prelude function resize.

Removed

• The prelude functions concat_to and flatten_to. They are often
  not necessary now, and otherwise resize is available.

Changed

• The prelude functions flatten and unflatten (and their
  multidimensional variants), as well as split, now have more
  precise types.

• Local and anonymous (lambda) functions that must return unique
  results (because they are passed to a higher order function that
  requires this) must now have an explicit return type ascription that
  declares this, using *. This is very rare (in practice
  unobserved) in real programs.

Fixed

• futhark doc produced some invalid links.

• flatten did not properly check for claimed negative array sizes.

• Type checker crash on some ill-typed programs (#1926).

• Some soundness bugs in memory short circuiting (#1927, #1930).

• Another compiler crash in block tiling (#1933, #1940).

• Global arrays with size parameters no longer have aliases.

• futhark eval no longer crashes on ambiguously typed expressions (#1946).

• A code motion pass was ignorant of consumption constraints, leading
  to compiler crash (#1947).

• Type checker could get confused and think unknown sizes were
  available when they really weren't (#1950).

• Some index optimisations removed certificates (#1952).

• GPU backends can now transpose arrays whose size does not fit in a
  32-bit integer (#1953).

• Bug in alias checking for the core language type checker (#1949).
  Actually (finally) a proper fix of #803.

• Defunctionalisation duplicates less code (#1968).