Bootstrapped compiler should check undefined variables in if branches

[Adrian Pop]

For example in CevalFunction.evaluateWhileStatement (modified on line 1438):

    case (_, _, _, _, _, st)
      equation
        (cache, Values.BOOL(boolean = b), st) = cevalExp(inCondition, inCache, inEnv, st);
        if b then
          (cache, env, loop_ctrl, st) = evaluateStatements(inStatements, cache, inEnv, st);
          (cache, env, loop_ctrl, st) = evaluateWhileStatement(inCondition, inStatements, cache, env, loop_ctrl, st);
        else
          loop_ctrl = NEXT();
          // env = inEnv;
        end if;
      then
        (cache, env, loop_ctrl, st);

env is not defined in the else branch.
This will compile code and for some models (i think it was MoistAir) will just crash.
Comment out env = inEnv; in the else branch and run the testsuite.

[Martin Sjölund]

The detection of assignment to uninitialised variables is conservative because the MSL uses the sort of patterns that are hard to detect if they are valid code (they are valid).

[Per Östlund]

Here's a case where we get a false positive instead:

function test
  output Integer j;
protected
  Boolean first := true;
algorithm
  for i in {1, 2, 3} loop
    if first then
      j := i;
      first := false;
    else
      j := j + i;
    end if;
  end for;
end test;

The compiler complains that j was used before given a value in the else-branch, but it does actually have a value since the first branch always runs first.

[Martin Sjölund]

Milestone changed to 1.9.3 since 1.9.2 was released.

[Martin Sjölund]

Moved to new milestone 1.9.4

[Martin Sjölund]

Milestone pushed to 1.9.5

[Martin Sjölund]

Milestone renamed

[Martin Sjölund]

Ticket retargeted after milestone closed

[Martin Sjölund]

Milestone moved to 1.12.0 due to 1.11.0 already being released.

[Francesco Casella]

The milestone of this ticket has been reassigned to "Future".

If you think the issue is still valid and relevant for you, please select milestone 1.13.0 for back-end, code generation and run-time issues, or 2.0.0 for front-end issues.

If you are aware that the problem is no longer present, please select the milestone corresponding to the version of OMC you used to check that, and set the status to "worksforme".

In both cases, a short informative comment would be welcome.