private static bool TryGet(ExpressionSyntax expression, SyntaxNodeAnalysisContext context, PooledSet <ExpressionSyntax> visited, out ITypeSymbol result, out ExpressionSyntax source)
{
switch (expression)
{
case MemberAccessExpressionSyntax memberAccess when memberAccess.Name.Identifier.ValueText == "ReturnType" &&
memberAccess.Expression is InvocationExpressionSyntax invocation &&
GetX.TryMatchGetMethod(invocation, context, out var reflectedMember, out _, out _, out _) &&
reflectedMember.Match == FilterMatch.Single &&
reflectedMember.Symbol is IMethodSymbol method:
source = memberAccess;
result = method.ReturnType;
return(true);
case MemberAccessExpressionSyntax memberAccess when memberAccess.Name.Identifier.ValueText == "FieldType" &&
memberAccess.Expression is InvocationExpressionSyntax invocation &&
GetX.TryMatchGetField(invocation, context, out var reflectedMember, out _, out _) &&
reflectedMember.Match == FilterMatch.Single &&
reflectedMember.Symbol is IFieldSymbol field:
source = memberAccess;
result = field.Type;
return(true);
case MemberAccessExpressionSyntax memberAccess when memberAccess.Name.Identifier.ValueText == "PropertyType" &&
memberAccess.Expression is InvocationExpressionSyntax invocation &&
GetX.TryMatchGetProperty(invocation, context, out var reflectedMember, out _, out _, out _) &&
reflectedMember.Match == FilterMatch.Single &&
reflectedMember.Symbol is IPropertySymbol field:
source = memberAccess;
result = field.Type;
return(true);
case TypeOfExpressionSyntax typeOf:
source = typeOf;
return(context.SemanticModel.TryGetType(typeOf.Type, context.CancellationToken, out result));
case InvocationExpressionSyntax invocation when invocation.ArgumentList is ArgumentListSyntax args &&
args.Arguments.Count == 0 &&
invocation.TryGetMethodName(out var name) &&
name == "GetType":
switch (invocation.Expression)
{
case MemberAccessExpressionSyntax typeAccess:
source = invocation;
if (context.SemanticModel.TryGetType(typeAccess.Expression, context.CancellationToken, out result))
{
if (result is INamedTypeSymbol namedType &&
namedType.ConstructedFrom?.SpecialType == SpecialType.System_Nullable_T)
{
result = namedType.TypeArguments[0];
}
return(true);
}
return(false);
case IdentifierNameSyntax _ when expression.TryFirstAncestor(out TypeDeclarationSyntax containingType):
source = invocation;
return(context.SemanticModel.TryGetSymbol(containingType, context.CancellationToken, out result));
case MemberBindingExpressionSyntax memberBinding when memberBinding.Parent?.Parent is ConditionalAccessExpressionSyntax conditionalAccess:
source = invocation;
return(context.SemanticModel.TryGetType(conditionalAccess.Expression, context.CancellationToken, out result));
}
break;
case InvocationExpressionSyntax candidate when TryMatchTypeGetType(candidate, context, out var typeName, out var ignoreCase):
source = candidate;
result = context.Compilation.GetTypeByMetadataName(typeName, ignoreCase.Value);
return(result != null);
case InvocationExpressionSyntax candidate when TryMatchAssemblyGetType(candidate, context, out var typeName, out var ignoreCase):
source = candidate;
result = Assembly.TryGet(candidate.Expression, context, out var assembly)
? assembly.GetTypeByMetadataName(typeName, ignoreCase.Value)
: null;
return(result != null);
case InvocationExpressionSyntax invocation when invocation.TryGetTarget(KnownSymbol.Type.GetGenericTypeDefinition, context.SemanticModel, context.CancellationToken, out _) &&
invocation.Expression is MemberAccessExpressionSyntax memberAccess &&
TryGet(memberAccess.Expression, context, visited, out var definingType, out _) &&
definingType is INamedTypeSymbol namedType:
source = invocation;
result = namedType.ConstructedFrom;
return(true);
case InvocationExpressionSyntax invocation when GetX.TryMatchGetNestedType(invocation, context, out var reflectedMember, out _, out _):
source = invocation;
result = reflectedMember.Symbol as ITypeSymbol;
return(result != null && reflectedMember.Match == FilterMatch.Single);
case InvocationExpressionSyntax invocation when invocation.TryGetTarget(KnownSymbol.Type.MakeGenericType, context.SemanticModel, context.CancellationToken, out _) &&
invocation.Expression is MemberAccessExpressionSyntax memberAccess &&
TypeArguments.TryCreate(invocation, context, out var typeArguments) &&
typeArguments.TryGetArgumentsTypes(context, out var types):
#pragma warning disable IDISP003 // Dispose previous before re-assigning.
using (visited = visited.IncrementUsage())
#pragma warning restore IDISP003 // Dispose previous before re-assigning.
{
source = invocation;
if (visited.Add(invocation) &&
TryGet(memberAccess.Expression, context, visited, out var definition, out _) &&
definition is INamedTypeSymbol namedType &&
ReferenceEquals(namedType, namedType.ConstructedFrom) &&
namedType.Arity == types.Length)
{
result = namedType.Construct(types);
return(result != null);
}
result = null;
return(false);
}
case ConditionalAccessExpressionSyntax conditionalAccess:
source = conditionalAccess;
return(TryGet(conditionalAccess.WhenNotNull, context, out result, out _));
}
if (expression.IsEither(SyntaxKind.IdentifierName, SyntaxKind.SimpleMemberAccessExpression) &&
context.SemanticModel.TryGetSymbol(expression, context.CancellationToken, out ISymbol local))
{
#pragma warning disable IDISP003 // Dispose previous before re-assigning.
using (visited = visited.IncrementUsage())
#pragma warning restore IDISP003 // Dispose previous before re-assigning.
{
source = null;
result = null;
return(AssignedValue.TryGetSingle(local, context.SemanticModel, context.CancellationToken, out var assignedValue) &&
visited.Add(assignedValue) &&
TryGet(assignedValue, context, visited, out result, out source));
}
}
source = null;
result = null;
return(false);
}
private static bool IsDefaultValueOfRegisteredType(ExpressionSyntax defaultValue, ITypeSymbol registeredType, SyntaxNodeAnalysisContext context, PooledSet <SyntaxNode> visited = null)
{
switch (defaultValue)
{
case ConditionalExpressionSyntax conditional:
#pragma warning disable IDISP003 // Dispose previous before re-assigning.
using (visited = visited.IncrementUsage())
#pragma warning restore IDISP003 // Dispose previous before re-assigning.
{
return(visited.Add(defaultValue) &&
IsDefaultValueOfRegisteredType(conditional.WhenTrue, registeredType, context, visited) &&
IsDefaultValueOfRegisteredType(conditional.WhenFalse, registeredType, context, visited));
}
case BinaryExpressionSyntax binary when binary.IsKind(SyntaxKind.CoalesceExpression):
#pragma warning disable IDISP003 // Dispose previous before re-assigning.
using (visited = visited.IncrementUsage())
#pragma warning restore IDISP003 // Dispose previous before re-assigning.
{
return(visited.Add(defaultValue) &&
IsDefaultValueOfRegisteredType(binary.Left, registeredType, context, visited) &&
IsDefaultValueOfRegisteredType(binary.Right, registeredType, context, visited));
}
}
if (context.SemanticModel.IsRepresentationPreservingConversion(defaultValue, registeredType, context.CancellationToken))
{
return(true);
}
if (context.SemanticModel.TryGetSymbol(defaultValue, context.CancellationToken, out ISymbol symbol))
{
if (symbol is IFieldSymbol field)
{
if (field.TrySingleDeclaration(context.CancellationToken, out var fieldDeclaration))
{
#pragma warning disable IDISP003 // Dispose previous before re-assigning.
using (visited = visited.IncrementUsage())
#pragma warning restore IDISP003 // Dispose previous before re-assigning.
{
if (fieldDeclaration.Declaration is VariableDeclarationSyntax variableDeclaration &&
variableDeclaration.Variables.TryLast(out var variable) &&
variable.Initializer is EqualsValueClauseSyntax initializer)
{
return(visited.Add(initializer.Value) &&
IsDefaultValueOfRegisteredType(initializer.Value, registeredType, context, visited));
}
return(fieldDeclaration.TryFirstAncestor <TypeDeclarationSyntax>(out var typeDeclaration) &&
AssignmentExecutionWalker.SingleFor(symbol, typeDeclaration, Scope.Instance, context.SemanticModel, context.CancellationToken, out var assignedValue) &&
visited.Add(assignedValue) &&
IsDefaultValueOfRegisteredType(assignedValue, registeredType, context, visited));
}
}
return(field.Type == KnownSymbol.Object);
}
if (symbol is IPropertySymbol property)
{
if (property.TrySingleDeclaration(context.CancellationToken, out PropertyDeclarationSyntax propertyDeclaration))
{
#pragma warning disable IDISP003 // Dispose previous before re-assigning.
using (visited = visited.IncrementUsage())
#pragma warning restore IDISP003 // Dispose previous before re-assigning.
{
if (propertyDeclaration.Initializer is EqualsValueClauseSyntax initializer)
{
return(visited.Add(initializer.Value) &&
IsDefaultValueOfRegisteredType(initializer.Value, registeredType, context, visited));
}
if (property.SetMethod == null &&
property.GetMethod is IMethodSymbol getMethod)
{
return(IsReturnValueOfRegisteredType(getMethod, visited));
}
return(propertyDeclaration.TryFirstAncestor <TypeDeclarationSyntax>(out var typeDeclaration) &&
AssignmentExecutionWalker.SingleFor(symbol, typeDeclaration, Scope.Instance, context.SemanticModel, context.CancellationToken, out var assignedValue) &&
visited.Add(assignedValue) &&
IsDefaultValueOfRegisteredType(assignedValue, registeredType, context, visited));
}
}
return(property.Type == KnownSymbol.Object);
}
if (symbol is IMethodSymbol method)
{
return(IsReturnValueOfRegisteredType(method, visited));
}
}
return(false);
bool IsReturnValueOfRegisteredType(IMethodSymbol method, PooledSet <SyntaxNode> v)
{
if (method.TrySingleMethodDeclaration(context.CancellationToken, out var target))
{
using (var walker = ReturnValueWalker.Borrow(target))
{
foreach (var returnValue in walker.ReturnValues)
{
if (!IsDefaultValueOfRegisteredType(returnValue, registeredType, context, v))
{
return(false);
}
}
return(true);
}
}
return(method.ReturnType == KnownSymbol.Object);
}
}