Method Promote

source/common/scripting/backend/codegen.cpp:3199–3272

//==========================================================================

bool FxBinary::Promote(FCompileContext &ctx, bool forceint, bool shiftop)
{
	// math operations of unsigned ints results in an unsigned int. (16 and 8 bit values never get here, they get promoted to regular ints elsewhere already.)
	if (left->ValueType == TypeUInt32 && right->ValueType == TypeUInt32)
	{
		ValueType = TypeUInt32;
	}
	// If one side is an unsigned 32-bit int and the other side is a signed 32-bit int, the signed side is implicitly converted to unsigned,
	else if (!ctx.FromDecorate && left->ValueType == TypeUInt32 && right->ValueType == TypeSInt32 && !shiftop && ctx.Version >= MakeVersion(4, 9, 0))
	{
		right = new FxIntCast(right, false, false, true);
		right = right->Resolve(ctx);
		ValueType = TypeUInt32;
	}
	else if (!ctx.FromDecorate && left->ValueType == TypeSInt32 && right->ValueType == TypeUInt32 && !shiftop && ctx.Version >= MakeVersion(4, 9, 0))
	{
		left = new FxIntCast(left, false, false, true);
		left = left->Resolve(ctx);
		ValueType = TypeUInt32;
	}
	else if (left->IsInteger() && right->IsInteger())
	{
		ValueType = TypeSInt32;		// Addition and subtraction forces all integer-derived types to signed int.
	}
	else if (!forceint)
	{
		ValueType = TypeFloat64;
		if (left->IsFloat() && right->IsInteger())
		{
			right = (new FxFloatCast(right))->Resolve(ctx);
		}
		else if (left->IsInteger() && right->IsFloat())
		{
			left = (new FxFloatCast(left))->Resolve(ctx);
		}
	}
	else if (ctx.FromDecorate)
	{
		// For DECORATE which allows floats here. ZScript does not.
		if (left->IsFloat())
		{
			left = new FxIntCast(left, ctx.FromDecorate);
			left = left->Resolve(ctx);
		}
		if (right->IsFloat())
		{
			right = new FxIntCast(right, ctx.FromDecorate);
			right = right->Resolve(ctx);
		}
		if (left == nullptr || right == nullptr)
		{
			delete this;
			return false;
		}
		ValueType = TypeSInt32;

	}
	else