Allow using negative index in nested list assignment

[jbdoderlein]

This PR fix a java.lang.ArrayIndexOutOfBoundsException exception when using negative index in nested list assignement.

The bug :

rascal>var1 = [[0],[1]];
list[list[int]]: [
  [0],
  [1]
]
rascal>var1[-1][-1]
int: 1
rascal>var1[1][-1] = 2;
list[list[int]]: [
  [0],
  [2]
]
rascal>var1[-1][-1] = 3;
java.lang.ArrayIndexOutOfBoundsException: -1 < 0
(internal error)
        at $(|main:///_dollar_|)

java.lang.ArrayIndexOutOfBoundsException: -1 < 0
        at io.usethesource.vallang.util.ShareableList.get(ShareableList.java:398)
        at io.usethesource.vallang.impl.persistent.List.get(List.java:81)
        at org.rascalmpl.semantics.dynamic.Assignable$Subscript.interpret(Assignable.java:610)
        at org.rascalmpl.semantics.dynamic.Assignable$Subscript.assignment(Assignable.java:449)
        at org.rascalmpl.semantics.dynamic.Statement$Assignment.interpret(Statement.java:227)
        at org.rascalmpl.interpreter.Evaluator.eval(Evaluator.java:830)
        at org.rascalmpl.semantics.dynamic.Command$Statement.interpret(Command.java:126)
        at org.rascalmpl.interpreter.Evaluator.eval(Evaluator.java:1066)
        at org.rascalmpl.interpreter.Evaluator.eval(Evaluator.java:915)
        at org.rascalmpl.interpreter.Evaluator.eval(Evaluator.java:866)
        at org.rascalmpl.repl.rascal.RascalInterpreterREPL.handleInput(RascalInterpreterREPL.java:236)
        at org.rascalmpl.repl.rascal.RascalReplServices.handleInput(RascalReplServices.java:109)
        at org.rascalmpl.repl.BaseREPL.handleInput(BaseREPL.java:217)
        at org.rascalmpl.repl.BaseREPL.run(BaseREPL.java:134)
        at org.rascalmpl.shell.REPLRunner.run(REPLRunner.java:30)
        at org.rascalmpl.shell.RascalShell.main(RascalShell.java:65)
        at org.rascalmpl.vscode.lsp.terminal.LSPTerminalREPL.main(LSPTerminalREPL.java:59)

With the PR :

rascal>var1 = [[0],[1]];
list[list[int]]: [
  [0],
  [1]
]
rascal>var1[-1][-1]
int: 1
rascal>var1[-1][-1] = 3;
list[list[int]]: [
  [0],
  [3]
]

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 46%. Comparing base (726cd6d) to head (68a7594).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##              main   #2587   +/-   ##
=======================================
  Coverage       46%     46%           
- Complexity    6632    6633    +1     
=======================================
  Files          793     793           
  Lines        65584   65586    +2     
  Branches      9822    9823    +1     
=======================================
+ Hits         30486   30493    +7     
+ Misses       32748   32743    -5     
  Partials      2350    2350           

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[DavyLandman]

Did you take this discussion into account? #2370 (comment)

[jbdoderlein]

Ok i didn't know about this issue. This is not the same issue but it is related.

Taking into account the documentation, there is missing IndexOutOfBound throw in the slicing method, I think I will try to open a new PR to fix these tomorrow.

[DavyLandman]

Would it be possible to add a small rascal unit test, just so that we never have a regression on this? (or the compiler might be sensative to this).

The lang::rascal::tests::basic::Lists would be the best place for this.