private ExpressionSyntax BuildFieldHashCodeCall(ISymbol fieldSymbol)
{
ITypeSymbol fieldType = (fieldSymbol as IFieldSymbol)?.Type ?? (fieldSymbol as IPropertySymbol).Type;
MemberAccessExpressionSyntax defaultComparer = DefaultEqualityComparer.AccessExpression(fieldType);
MemberAccessExpressionSyntax defaultGetHashCodeMethod = MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, defaultComparer, _getHashCodeName);
MemberAccessExpressionSyntax fieldAccess = MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, ThisExpression(), IdentifierName(fieldSymbol.Name));
InvocationExpressionSyntax getHashCodeCall = InvocationExpression(defaultGetHashCodeMethod).AddArgumentListArguments(Argument(fieldAccess));
return(getHashCodeCall);
}
private static ExpressionSyntax BuildFieldEqualityCall(ISymbol fieldSymbol)
{
ITypeSymbol fieldType = (fieldSymbol as IFieldSymbol)?.Type ?? (fieldSymbol as IPropertySymbol).Type;
bool declaresEqualityOperator = fieldType
.GetMembers()
.OfType <IMethodSymbol>()
.Where(m => m.MethodKind == MethodKind.BuiltinOperator || m.MethodKind == MethodKind.UserDefinedOperator)
.Where(m => m.Name == "op_Equality")
.Any();
// If the field type declares == operator, we can safely use it.
// This provides better readability in a lot of cases.
if (declaresEqualityOperator)
{
return(BinaryExpression
(
SyntaxKind.EqualsExpression,
MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, ThisExpression(), IdentifierName(fieldSymbol.Name)),
MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, IdentifierName(_otherArg), IdentifierName(fieldSymbol.Name))
));
}
// Otherwise, we have to resort to EqualityComparer<T>.Default.Equals( this._field, other._field )
MemberAccessExpressionSyntax defaultProperty = DefaultEqualityComparer.AccessExpression(fieldType);
MemberAccessExpressionSyntax equalsMethod = MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, defaultProperty, IdentifierName("Equals"));
InvocationExpressionSyntax invocation = InvocationExpression(equalsMethod);
invocation = invocation
.AddArgumentListArguments
(
Argument(MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, ThisExpression(), IdentifierName(fieldSymbol.Name))),
Argument(MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, IdentifierName(_otherArg), IdentifierName(fieldSymbol.Name)))
);
return(invocation);
}