out char arguments don't get boxed correctly.

[otac0n]

public void A()
{
    char c;
    if (!this.B(out c) && c == ':')
    {
        return;
    }
    return;
}

public bool B(out char c)
{
    c = ':';
    return true;
}

  function Class1_A () {
    var c = String.fromCharCode(new JSIL.BoxedVariable("\x00"));
    var flag = !this.B(/* ref */ c) && 
    (((c.get()).charCodeAt(0) | 0) === ((":").charCodeAt(0) | 0));
    if (flag) {
    }
  }; 

  function Class1_B (/* ref */ c) {
    c.set((":").charCodeAt(0));
    return true;
  }; 

[otac0n]

In IntroduceVariableReferences, I see this comment:

var newDeclaration = new JSVariableDeclarationStatement(new JSBinaryOperatorExpression(
    JSOperator.Assignment,
    // We have to use a constructed ref to the variable here, otherwise
    //  the declaration will look like 'var x.value = foo'
    new JSVariable(variable.Identifier, variable.IdentifierType, variable.Function),
    JSIL.NewReference(initialValue), 
    newVariable.IdentifierType
));

While in IntroduceCharCasts, I see this logic:

if (boe.Operator == JSOperator.Assignment && (leftType.FullName == "System.Char") && (rightType.FullName != "System.Char"))
{
    boe.ReplaceChild(boe.Right, CastToChar(boe.Right));
}
if (boe.Operator == JSOperator.Assignment && (leftType.FullName != "System.Char") && (rightType.FullName == "System.Char"))
{
    boe.ReplaceChild(boe.Right, CastToInteger(boe.Right));
}

The problem here being that the right type for the assignment is System.Char&.

Any suggestions for a fix?

[otac0n]

So, for my purposes, just ignoring the warning seems to have fixed it:

var newDeclaration = new JSVariableDeclarationStatement(new JSBinaryOperatorExpression(
    JSOperator.Assignment,
    newVariable,
    JSIL.NewReference(initialValue), 
    newVariable.IdentifierType
));

Contrary to the warning, the code that gets generated now looks like this:

  function Class1_A () {
    var c = new JSIL.BoxedVariable("\x00");
    if (!$thisType.B(/* ref */ c)) {
      return;
    }
  }; 

  function Class1_B (/* ref */ c) {
    c.set(":");
    return true;
  }; 

[kg]

The problem here being that the right type for the assignment is System.Char&.

Stripping the reference part of the type is probably okay here. Maybe try that. There's a method in TypeUtil that does it.