Example #1
0
        internal void LookupExtensionMethodsInUsings(
            ArrayBuilder<MethodSymbol> methods,
            string name,
            int arity,
            LookupOptions options,
            bool callerIsSemanticModel)
        {
            Debug.Assert(methods.Count == 0);

            // We need to avoid collecting multiple candidates for an extension method imported both through a namespace and a static class
            // We will look for duplicates only if both of the following flags are set to true
            bool seenNamespaceWithExtensionMethods = false;
            bool seenStaticClassWithExtensionMethods = false;

            foreach (var nsOrType in this.Usings)
            {
                switch (nsOrType.NamespaceOrType.Kind)
                {
                    case SymbolKind.Namespace:
                        {
                            var count = methods.Count;
                            ((NamespaceSymbol)nsOrType.NamespaceOrType).GetExtensionMethods(methods, name, arity, options);

                            // If we found any extension methods, then consider this using as used.
                            if (methods.Count != count)
                            {
                                MarkImportDirective(nsOrType.UsingDirective, callerIsSemanticModel);
                                seenNamespaceWithExtensionMethods = true;
                            }

                            break;
                        }

                    case SymbolKind.NamedType:
                        {
                            var count = methods.Count;
                            ((NamedTypeSymbol)nsOrType.NamespaceOrType).GetExtensionMethods(methods, name, arity, options);

                            // If we found any extension methods, then consider this using as used.
                            if (methods.Count != count)
                            {
                                MarkImportDirective(nsOrType.UsingDirective, callerIsSemanticModel);
                                seenStaticClassWithExtensionMethods = true;
                            }

                            break;
                        }
                }
            }

            if (seenNamespaceWithExtensionMethods && seenStaticClassWithExtensionMethods)
            {
                var methodsNoDuplicates = ArrayBuilder<MethodSymbol>.GetInstance();
                methodsNoDuplicates.AddRange(methods.Distinct());
                if (methodsNoDuplicates.Count < methods.Count)
                {
                    methods.Clear();
                    methods.AddRange(methodsNoDuplicates);
                }

                methodsNoDuplicates.Free();
            }
        }