InvalidProgramException when nullable result is ignored

[exyi]

The error occurs when I have a Convert expression returning Nullable, but I ignore the result. For example

[Test]
public void Case2_A()
{
  var p = Parameter(typeof(int), "tmp0");
  var expr = 
    Lambda<Action<int>>(Block(
      Convert(p, typeof(int?)),
      Default(typeof(void))), p);

  var f = expr.CompileFast();
  f(2);
}

Or similar:

[Test]
public void Case2_B()
{
  var p = Parameter(typeof(int), "tmp0");
  var expr = 
    Lambda<Action<int>>(Convert(p, typeof(int?)), new[] { p });
  var f = expr.CompileFast();
  f(2);
}

In these simple cases, I could just not place the ignored convert there, but it also fails in more complex cases when the conversion is nested in conditions/blocks, but the result is still not used in the end.

[dadhi]

@exyi Great that reproducible samples are small. Will check.

If you're interested, you may look how would I address, test and fix the issues (look at fix for #307 as an example 3a04eed, 35b9a8f)

In other words, PRs are welcome ;)