Deep list pattern match does not backtrack correctly

[msteindorfer]

The following two examples should produce the same output:

rascal>[ v | [_*,/v,_*] := [[1,2], [3,4]]]
list[int]: [1,2,3]

rascal>[ v | [_*, x,_*] := [[1,2], [3,4]], /v := x];
list[value]: [
  1,
  2,
  [1,2],
  3,
  4,
  [3,4]
]

It seems that backtracking is not implemented correctly for deep list matching in the former case.

Deep set pattern matching does not exhibit the same problem:

rascal>{ v | {_*,/v,_*} := {{1,2}, {3,4}}}
set[value]: {1,2,4,{3,4},{1,2},3}

rascal>{ v | {_*, x,_*} := {{1,2}, {3,4}}, /v := x}
set[value]: {1,2,4,{3,4},{1,2},3}

I propose to also add regression tests for these different ways of deep pattern matching.

[PaulKlint]

Happy to report that the compiled version of the above pattern match does generate the correct answer.

[jurgenvinju]

This goes wrong with more nested patterns which are not variables, also normal nodes apparently...