public override void Visit(AssignExpressionNode node)
{
var left = node.LeftOperand;
var op = node.OperatorToken;
if (!op.IsMissing)
{
switch (left)
{
case IndexExpressionNode _:
case FieldAccessExpressionNode _:
break;
case IdentifierExpressionNode inode:
var ident = inode.IdentifierToken;
if (!ident.IsMissing && !_scope.IsMutable(ident.Text))
{
Error(node, SyntaxDiagnosticKind.InvalidAssignmentTarget, op.Location,
$"'{ident}' does not represent a mutable variable");
}
break;
default:
Error(node, SyntaxDiagnosticKind.InvalidAssignmentTarget, op.Location,
"Assignment target must be an index, field access, or identifier expression");
break;
}
}
base.Visit(node);
}
protected override AssignmentState handleAssign(AssignExpressionNode assign, HashSet <StatementNode> visited, bool nested)
{
if (handleExpression(assign.Right, visited, true) == AssignmentState.Assigned)
{
return(AssignmentState.Assigned);
}
if (assign.Left.ExpressionKind == ExpressionKind.SimpleName && assign.Operator == AssignOperator.Assign)
{
var linfo = assign.Left.getUserData(typeof(ExpressionInfo));
var member = linfo.Member;
if (member.MemberKind == MemberKind.Local && member == assignmentChecker.uninitializedLocalInfo.local)
{
return(AssignmentState.Assigned);
}
}
else
{
return(handleExpression(assign.Left, visited, true));
}
return(AssignmentState.NotAssigned);
}
protected override Void handleAssign(AssignExpressionNode assign, Set <TypeInfo> dependencies, bool nested)
{
handleExpression(assign.Left, dependencies, true);
handleExpression(assign.Right, dependencies, true);
return(null);
}
public override TreeReference Visit(AssignExpressionNode node, TreeReference state)
{
return(new TreeAssignNode(_context, node.OperatorToken.Location, Visit(node.LeftOperand),
Visit(node.RightOperand)));
}