unassigned local variable can sometimes hold values other than nil

[ShadowTheAge]

lua code

for k,v in pairs{1} do local my; return my; end

Expected result: my == nil Actual result my is a table

(I am using MoonSharp for Unity)

[ghost]

This is indeed an error, what seems to be happening is that as nothing is assigned to my, it receives the table {1}.

[Aberro]

I've investigated into same case and unassigned local variables accesses latest stack value and tries to interpret it as a tuple, assigning it's second value to local scope variable. I think AssignmentStatement should check whether rvalue array is not less than lvalue array and expand it with nil values pushed to stack if it is.

[Aberro]

I'll move my issue here.

This will output current value from the stack, while it should be nil value. `local x print(x)'

AssignmentStatement.Compile tells SymbolRefExpression to emit OpCode.StoreLcl with stackofs=0 and tupleidx=1 and this makes no sense in given context.

[Aberro]

Looks like I've finally figured it out, after several incorrect fixes: in AssignmentStatement.cs, replace m_RValues initialization:

40:			else
41:			{
----
42:				m_RValues = new List<Expression>();
+++
   				if(names.Count > 0)
					m_RValues = new List<Expression>(new Expression[] { new LiteralExpression(lcontext, DynValue.Nil) });
+++
43:			}

This should initialize uninitialized values with nil values.

[Aberro]

fix in pull request: https://github.com/moonsharp-devs/moonsharp/pull/280