public async Task <ExpressionSyntax> ConvertReferenceOrNothingComparisonOrNullAsync(VBSyntax.ExpressionSyntax exprNode, bool negateExpression = false)
{
if (!(exprNode is VBSyntax.BinaryExpressionSyntax node) ||
!node.IsKind(VBasic.SyntaxKind.IsExpression, VBasic.SyntaxKind.EqualsExpression, VBasic.SyntaxKind.IsNotExpression, VBasic.SyntaxKind.NotEqualsExpression))
{
return(null);
}
var notted =
node.IsKind(VBasic.SyntaxKind.IsNotExpression, VBasic.SyntaxKind.NotEqualsExpression) ||
negateExpression;
var isReferenceComparison = node.IsKind(VBasic.SyntaxKind.IsExpression, VBasic.SyntaxKind.IsNotExpression);
if (ArgComparedToNull(node) is {} vbOtherArg)
{
var csOtherArg = await ConvertIsOrIsNotExpressionArgAsync(vbOtherArg);
return(notted
? CommonConversions.NotNothingComparison(csOtherArg, isReferenceComparison)
: CommonConversions.NothingComparison(csOtherArg, isReferenceComparison));
}
if (isReferenceComparison)
{
var lhs = await ConvertIsOrIsNotExpressionArgAsync(node.Left);
var rhs = await ConvertIsOrIsNotExpressionArgAsync(node.Right);
var equalityCheck = new KnownMethod(nameof(System), nameof(Object), nameof(object.ReferenceEquals))
.Invoke(_visualBasicEqualityComparison.ExtraUsingDirectives,
ConvertTo(node.Left, lhs, SpecialType.System_Object), rhs);
return(notted
? SyntaxFactory.PrefixUnaryExpression(SyntaxKind.LogicalNotExpression, equalityCheck)
: equalityCheck);
}
return(null);
}
public async Task <ExpressionSyntax> ConvertNothingComparisonOrNullAsync(VBSyntax.ExpressionSyntax exprNode, bool negateExpression = false)
{
if (!(exprNode is VBSyntax.BinaryExpressionSyntax node) || !node.IsKind(VBasic.SyntaxKind.IsExpression, VBasic.SyntaxKind.EqualsExpression, VBasic.SyntaxKind.IsNotExpression, VBasic.SyntaxKind.NotEqualsExpression))
{
return(null);
}
ExpressionSyntax otherArgument;
if (node.Left.IsKind(VBasic.SyntaxKind.NothingLiteralExpression))
{
otherArgument = (ExpressionSyntax) await ConvertIsOrIsNotExpressionArgAsync(node.Right);
}
else if (node.Right.IsKind(VBasic.SyntaxKind.NothingLiteralExpression))
{
otherArgument = (ExpressionSyntax) await ConvertIsOrIsNotExpressionArgAsync(node.Left);
}
else
{
return(null);
}
var isReference = node.IsKind(VBasic.SyntaxKind.IsExpression, VBasic.SyntaxKind.IsNotExpression);
var notted = node.IsKind(VBasic.SyntaxKind.IsNotExpression, VBasic.SyntaxKind.NotEqualsExpression) || negateExpression;
return(notted ? CommonConversions.NotNothingComparison(otherArgument, isReference) : CommonConversions.NothingComparison(otherArgument, isReference));
}