Inferred nullability should flow into anonymous type fields #24018
Description
The anonymous type field in the following should be declared as string rather than string?. Instead, y.ToString() generates a warning that y may be null.
using System.Linq;
class C
{
static void Main()
{
var x = new string[] { "" };
var y = x.Select(s => new { s }).First().s;
y.ToString();
}
}
(jcouv update:)
I also noticed a reference to the feature flag in binding logic for anonymous types, which seems wrong (the feature flag should only affect diagnostics, but not symbols from binding).
private BoundExpression BindAnonymousObjectCreation(AnonymousObjectCreationExpressionSyntax node, DiagnosticBag diagnostics)
{
...
// calculate the expression's type and report errors if needed
TypeSymbol fieldType = GetAnonymousTypeFieldType(boundExpressions[i], fieldInitializer, diagnostics, ref hasError);
// build anonymous type field descriptor
fieldSyntaxNodes[i] = (nameToken.Kind() == SyntaxKind.IdentifierToken) ? (CSharpSyntaxNode)nameToken.Parent : fieldInitializer;
fields[i] = new AnonymousTypeField(fieldName == null ? "$" + i.ToString() : fieldName, fieldSyntaxNodes[i].Location,
TypeSymbolWithAnnotations.Create(fieldType, isNullableIfReferenceType: node.IsFeatureStaticNullCheckingEnabled())); // <===== THIS SEEMS FISHY
...
}