C# TypeSymbol.AsImmutableOrNull方法代码示例

 /// <summary>
 /// Retrieves anonymous type properties types
 /// </summary>
 internal static ImmutableArray<TypeSymbol> GetAnonymousTypePropertyTypes(NamedTypeSymbol type)
 {
     Debug.Assert(type.IsAnonymousType);
     var anonymous = (AnonymousTypePublicSymbol)type;
     var fields = anonymous.TypeDescriptor.Fields;
     TypeSymbol[] types = new TypeSymbol[fields.Length];
     for (int i = 0; i < fields.Length; i++)
     {
         types[i] = fields[i].Type;
     }
     return types.AsImmutableOrNull();
 }

        private MethodSymbol GetMethodWrapperForBaseNonVirtualCall(MethodSymbol methodBeingCalled, SyntaxNode syntax)
        {
            var newMethod = GetOrCreateBaseFunctionWrapper(methodBeingCalled, syntax);
            if (!newMethod.IsGenericMethod)
            {
                return newMethod;
            }

            //  for generic methods we need to construct the method to be actually called
            Debug.Assert(methodBeingCalled.IsGenericMethod);
            var typeArgs = methodBeingCalled.TypeArguments;
            Debug.Assert(typeArgs.Length == newMethod.Arity);

            TypeSymbol[] visitedTypeArgs = new TypeSymbol[typeArgs.Length];
            for (int i = 0; i < visitedTypeArgs.Length; i++)
            {
                visitedTypeArgs[i] = VisitType(typeArgs[i]);
            }
            return newMethod.Construct(visitedTypeArgs.AsImmutableOrNull());
        }

        /// <summary>
        /// If the extension method is applicable based on the "this" argument type, return
        /// the method constructed with the inferred type arguments. If the method is not an
        /// unconstructed generic method, type inference is skipped. If the method is not
        /// applicable, or if constraints when inferring type parameters from the "this" type
        /// are not satisfied, the return value is null.
        /// </summary>
        public static MethodSymbol InferExtensionMethodTypeArguments(this MethodSymbol method, TypeSymbol thisType, Compilation compilation, ref HashSet<DiagnosticInfo> useSiteDiagnostics)
        {
            Debug.Assert(method.IsExtensionMethod);
            Debug.Assert((object)thisType != null);

            if (!method.IsGenericMethod || method != method.ConstructedFrom)
            {
                return method;
            }

            // We never resolve extension methods on a dynamic receiver.
            if (thisType.IsDynamic())
            {
                return null;
            }

            var containingAssembly = method.ContainingAssembly;
            var errorNamespace = containingAssembly.GlobalNamespace;
            var conversions = new TypeConversions(containingAssembly.CorLibrary);

            // There is absolutely no plausible syntax/tree that we could use for these
            // synthesized literals.  We could be speculatively binding a call to a PE method.
            var syntaxTree = CSharpSyntaxTree.Dummy;
            var syntax = (CSharpSyntaxNode)syntaxTree.GetRoot();

            // Create an argument value for the "this" argument of specific type,
            // and pass the same bad argument value for all other arguments.
            var thisArgumentValue = new BoundLiteral(syntax, ConstantValue.Bad, thisType) { WasCompilerGenerated = true };
            var otherArgumentType = new ExtendedErrorTypeSymbol(errorNamespace, name: string.Empty, arity: 0, errorInfo: null, unreported: false);
            var otherArgumentValue = new BoundLiteral(syntax, ConstantValue.Bad, otherArgumentType) { WasCompilerGenerated = true };

            var paramCount = method.ParameterCount;
            var arguments = new BoundExpression[paramCount];
            var argumentTypes = new TypeSymbol[paramCount];
            for (int i = 0; i < paramCount; i++)
            {
                var argument = (i == 0) ? thisArgumentValue : otherArgumentValue;
                arguments[i] = argument;
                argumentTypes[i] = argument.Type;
            }

            var typeArgs = MethodTypeInferrer.InferTypeArgumentsFromFirstArgument(
                conversions,
                method,
                argumentTypes.AsImmutableOrNull(),
                arguments.AsImmutableOrNull(),
                ref useSiteDiagnostics);

            if (typeArgs.IsDefault)
            {
                return null;
            }

            int firstNullInTypeArgs = -1;

            // For the purpose of constraint checks we use error type symbol in place of type arguments that we couldn't infer from the first argument.
            // This prevents constraint checking from failing for corresponding type parameters. 
            var typeArgsForConstraintsCheck = typeArgs;
            for (int i = 0; i < typeArgsForConstraintsCheck.Length; i++)
            {
                if ((object)typeArgsForConstraintsCheck[i] == null)
                {
                    firstNullInTypeArgs = i;
                    var builder = ArrayBuilder<TypeSymbol>.GetInstance();
                    builder.AddRange(typeArgs, firstNullInTypeArgs);

                    for (; i < typeArgsForConstraintsCheck.Length; i++)
                    {
                        builder.Add(typeArgsForConstraintsCheck[i] ?? ErrorTypeSymbol.UnknownResultType);
                    }

                    typeArgsForConstraintsCheck = builder.ToImmutableAndFree();
                    break;
                }
            }

            // Check constraints.
            var diagnosticsBuilder = ArrayBuilder<TypeParameterDiagnosticInfo>.GetInstance();
            var typeParams = method.TypeParameters;
            var substitution = new TypeMap(typeParams, typeArgsForConstraintsCheck.SelectAsArray(TypeMap.TypeSymbolAsTypeWithModifiers));
            ArrayBuilder<TypeParameterDiagnosticInfo> useSiteDiagnosticsBuilder = null;
            var success = method.CheckConstraints(conversions, substitution, typeParams, typeArgsForConstraintsCheck, compilation, diagnosticsBuilder, ref useSiteDiagnosticsBuilder);
            diagnosticsBuilder.Free();

            if (useSiteDiagnosticsBuilder != null && useSiteDiagnosticsBuilder.Count > 0)
            {
                if (useSiteDiagnostics == null)
                {
                    useSiteDiagnostics = new HashSet<DiagnosticInfo>();
                }

                foreach (var diag in useSiteDiagnosticsBuilder)
                {
//.........这里部分代码省略.........

        /// <summary>
        /// If the extension method is applicable based on the "this" argument type, return
        /// the method constructed with the inferred type arguments. If the method is not an
        /// unconstructed generic method, type inference is skipped. If the method is not
        /// applicable, or if constraints when inferring type parameters from the "this" type
        /// are not satisfied, the return value is null.
        /// </summary>
        public static MethodSymbol InferExtensionMethodTypeArguments(this MethodSymbol method, TypeSymbol thisType, Compilation compilation, ref HashSet<DiagnosticInfo> useSiteDiagnostics)
        {
            Debug.Assert(method.IsExtensionMethod);
            Debug.Assert((object)thisType != null);

            if (!method.IsGenericMethod || method != method.ConstructedFrom)
            {
                return method;
            }

            // We never resolve extension methods on a dynamic receiver.
            if (thisType.IsDynamic())
            {
                return null;
            }

            var containingAssembly = method.ContainingAssembly;
            var errorNamespace = containingAssembly.GlobalNamespace;
            var conversions = new TypeConversions(containingAssembly.CorLibrary);

            // There is absolutely no plausible syntax/tree that we could use for these
            // synthesized literals.  We could be speculatively binding a call to a PE method.
            var syntaxTree = CSharpSyntaxTree.Dummy;
            var syntax = (CSharpSyntaxNode)syntaxTree.GetRoot();

            // Create an argument value for the "this" argument of specific type,
            // and pass the same bad argument value for all other arguments.
            var thisArgumentValue = new BoundLiteral(syntax, ConstantValue.Bad, thisType) { WasCompilerGenerated = true };
            var otherArgumentType = new ExtendedErrorTypeSymbol(errorNamespace, name: string.Empty, arity: 0, errorInfo: null, unreported: false);
            var otherArgumentValue = new BoundLiteral(syntax, ConstantValue.Bad, otherArgumentType) { WasCompilerGenerated = true };

            var paramCount = method.ParameterCount;
            var arguments = new BoundExpression[paramCount];
            var argumentTypes = new TypeSymbol[paramCount];
            for (int i = 0; i < paramCount; i++)
            {
                var argument = (i == 0) ? thisArgumentValue : otherArgumentValue;
                arguments[i] = argument;
                argumentTypes[i] = argument.Type;
            }

            var typeArgs = MethodTypeInferrer.InferTypeArgumentsFromFirstArgument(
                conversions,
                method,
                argumentTypes.AsImmutableOrNull(),
                arguments.AsImmutableOrNull(),
                ref useSiteDiagnostics);

            if (typeArgs.IsDefault)
            {
                return null;
            }

            // Check constraints.
            var diagnosticsBuilder = ArrayBuilder<TypeParameterDiagnosticInfo>.GetInstance();
            var typeParams = method.TypeParameters;
            var substitution = new TypeMap(typeParams, typeArgs);
            ArrayBuilder<TypeParameterDiagnosticInfo> useSiteDiagnosticsBuilder = null;
            var success = method.CheckConstraints(conversions, substitution, method.TypeParameters, typeArgs, compilation, diagnosticsBuilder, ref useSiteDiagnosticsBuilder);
            diagnosticsBuilder.Free();

            if (useSiteDiagnosticsBuilder != null && useSiteDiagnosticsBuilder.Count > 0)
            {
                if (useSiteDiagnostics == null)
                {
                    useSiteDiagnostics = new HashSet<DiagnosticInfo>();
                }

                foreach (var diag in useSiteDiagnosticsBuilder)
                {
                    useSiteDiagnostics.Add(diag.DiagnosticInfo);
                }
            }

            if (!success)
            {
                return null;
            }

            return method.Construct(typeArgs);
        }