protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken)
{
return
context.IsGlobalStatementContext ||
context.IsMemberDeclarationContext(
validModifiers: s_validMemberModifiers,
validTypeDeclarations: SyntaxKindSet.ClassOnlyTypeDeclarations,
canBePartial: false,
cancellationToken: cancellationToken) ||
context.IsTypeDeclarationContext(
validModifiers: s_validTypeModifiers,
validTypeDeclarations: SyntaxKindSet.ClassStructTypeDeclarations,
canBePartial: false,
cancellationToken: cancellationToken);
}
protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken)
{
// cases:
// extern |
// extern a|
var token = context.TargetToken;
if (token.Kind() == SyntaxKind.ExternKeyword)
{
// members can be 'extern' but we don't want
// 'alias' to show up in a 'type'.
return token.GetAncestor<TypeDeclarationSyntax>() == null;
}
return false;
}
protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken)
{
return
(IsInBreakableConstructContext(context) ||
context.TargetToken.IsAfterYieldKeyword());
}
private static ImmutableArray <ISymbol> GetSymbolsOffOfName(
CSharpSyntaxContext context,
NameSyntax name,
CancellationToken cancellationToken)
{
// Check if we're in an interesting situation like this:
//
// int i = 5;
// i. // <-- here
// List<string> ml = new List<string>();
// The problem is that "i.List<string>" gets parsed as a type. In this case we need to
// try binding again as if "i" is an expression and not a type. In order to do that, we
// need to speculate as to what 'i' meant if it wasn't part of a local declaration's
// type.
if (name.IsFoundUnder <LocalDeclarationStatementSyntax>(d => d.Declaration.Type))
{
var speculativeBinding = context.SemanticModel.GetSpeculativeSymbolInfo(name.SpanStart, name, SpeculativeBindingOption.BindAsExpression);
var container = context.SemanticModel.GetSpeculativeTypeInfo(name.SpanStart, name, SpeculativeBindingOption.BindAsExpression).Type;
return(GetSymbolsOffOfBoundExpression(context, name, name, speculativeBinding, container, cancellationToken));
}
// We're in a name-only context, since if we were an expression we'd be a
// MemberAccessExpressionSyntax. Thus, let's do other namespaces and types.
var nameBinding = context.SemanticModel.GetSymbolInfo(name, cancellationToken);
var symbol = nameBinding.Symbol as INamespaceOrTypeSymbol;
if (symbol != null)
{
if (context.IsNameOfContext)
{
return(context.SemanticModel.LookupSymbols(position: name.SpanStart, container: symbol));
}
var symbols = context.SemanticModel.LookupNamespacesAndTypes(
position: name.SpanStart,
container: symbol);
if (context.IsNamespaceDeclarationNameContext)
{
var declarationSyntax = name.GetAncestorOrThis <NamespaceDeclarationSyntax>();
return(symbols.WhereAsArray(s => IsNonIntersectingNamespace(s, declarationSyntax)));
}
// Filter the types when in a using directive, but not an alias.
//
// Cases:
// using | -- Show namespaces
// using A.| -- Show namespaces
// using static | -- Show namespace and types
// using A = B.| -- Show namespace and types
var usingDirective = name.GetAncestorOrThis <UsingDirectiveSyntax>();
if (usingDirective != null && usingDirective.Alias == null)
{
if (usingDirective.StaticKeyword.IsKind(SyntaxKind.StaticKeyword))
{
return(symbols.WhereAsArray(s => !s.IsDelegateType() && !s.IsInterfaceType()));
}
else
{
symbols = symbols.WhereAsArray(s => s.IsNamespace());
}
}
if (symbols.Any())
{
return(symbols);
}
}
return(ImmutableArray <ISymbol> .Empty);
}
private static bool IsUnsafeParameterTypeContext(CSharpSyntaxContext context)
{
return
(context.TargetToken.IsUnsafeContext() &&
context.IsParameterTypeContext);
}
private static bool IsMemberReturnTypeContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken) => context.SyntaxTree.IsGlobalMemberDeclarationContext(position, SyntaxKindSet.AllGlobalMemberModifiers, cancellationToken) || context.IsMemberDeclarationContext(validModifiers: s_validClassInterfaceRecordModifiers, validTypeDeclarations: SyntaxKindSet.ClassInterfaceRecordTypeDeclarations, canBePartial: true, cancellationToken) || context.IsMemberDeclarationContext(validModifiers: s_validStructModifiers, validTypeDeclarations: SyntaxKindSet.StructOnlyTypeDeclarations, canBePartial: false, cancellationToken);
protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken)
{
// cases:
// expr |
return(!context.IsInNonUserCode && context.IsIsOrAsContext);
}
protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken) => context.SyntaxTree.IsParamsModifierContext(context.Position, context.LeftToken);
protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken)
{
return(context.ContainingTypeDeclaration == null &&
context.IsTypeDeclarationContext(s_validModifiers, SyntaxKindSet.AllTypeDeclarations, canBePartial: true, cancellationToken));
}
private static bool IsValidNewByRefContext(SyntaxTree syntaxTree, int position, CSharpSyntaxContext context, CancellationToken cancellationToken)
{
return
(IsValidRefExpressionContext(context) ||
context.IsDelegateReturnTypeContext ||
syntaxTree.IsGlobalMemberDeclarationContext(position, RefGlobalMemberModifiers, cancellationToken) ||
context.IsMemberDeclarationContext(
validModifiers: RefMemberModifiers,
validTypeDeclarations: SyntaxKindSet.ClassInterfaceStructTypeDeclarations,
canBePartial: true,
cancellationToken: cancellationToken));
}
private static bool IsValidContextForType(CSharpSyntaxContext context, CancellationToken cancellationToken)
{
return(context.IsTypeDeclarationContext(validModifiers: SyntaxKindSet.AllTypeModifiers,
validTypeDeclarations: SyntaxKindSet.ClassInterfaceStructTypeDeclarations, canBePartial: true, cancellationToken));
}
private static bool IsValidRefExpressionContext(CSharpSyntaxContext context)
{
// {
// ref var x ...
//
if (context.IsStatementContext)
{
return(true);
}
//
// ref Goo(int x, ...
//
if (context.IsGlobalStatementContext)
{
return(true);
}
var token = context.TargetToken;
switch (token.Kind())
{
// {
// return ref ...
//
case SyntaxKind.ReturnKeyword:
return(true);
// {
// () => ref ...
//
case SyntaxKind.EqualsGreaterThanToken:
return(true);
// {
// for (ref var x ...
//
// foreach (ref var x ...
//
case SyntaxKind.OpenParenToken:
var previous = token.GetPreviousToken(includeSkipped: true);
return(previous.IsKind(SyntaxKind.ForKeyword) ||
previous.IsKind(SyntaxKind.ForEachKeyword));
// {
// ref var x = ref
//
case SyntaxKind.EqualsToken:
var parent = token.Parent;
return(parent?.Kind() == SyntaxKind.SimpleAssignmentExpression ||
parent?.Parent?.Kind() == SyntaxKind.VariableDeclarator);
// {
// var x = true ?
// var x = true ? ref y :
case SyntaxKind.QuestionToken:
case SyntaxKind.ColonToken:
return(token.Parent?.Kind() == SyntaxKind.ConditionalExpression);
}
return(false);
}
protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken) => context.IsAnyExpressionContext || context.IsStatementContext || context.IsGlobalStatementContext || context.LeftToken.IsInCastExpressionTypeWhereExpressionIsMissingOrInNextLine();
public override async Task ProduceCompletionListAsync(CompletionListContext context)
{
var document = context.Document;
var position = context.Position;
var options = context.Options;
var cancellationToken = context.CancellationToken;
var span = new TextSpan(position, length: 0);
var semanticModel = await document.GetSemanticModelForSpanAsync(span, cancellationToken).ConfigureAwait(false);
var syntaxTree = semanticModel.SyntaxTree;
var syntaxFacts = document.GetLanguageService <ISyntaxFactsService>();
var semanticFacts = document.GetLanguageService <ISemanticFactsService>();
if (syntaxFacts.IsInNonUserCode(syntaxTree, position, cancellationToken) ||
semanticFacts.IsPreProcessorDirectiveContext(semanticModel, position, cancellationToken))
{
return;
}
if (!syntaxTree.IsRightOfDotOrArrowOrColonColon(position, cancellationToken))
{
return;
}
var node = syntaxTree.FindTokenOnLeftOfPosition(position, cancellationToken)
.GetPreviousTokenIfTouchingWord(position)
.Parent;
if (node.Kind() != SyntaxKind.ExplicitInterfaceSpecifier)
{
return;
}
// Bind the interface name which is to the left of the dot
var name = ((ExplicitInterfaceSpecifierSyntax)node).Name;
var symbol = semanticModel.GetSymbolInfo(name, cancellationToken).Symbol as ITypeSymbol;
if (symbol?.TypeKind != TypeKind.Interface)
{
return;
}
var members = semanticModel.LookupSymbols(
position: name.SpanStart,
container: symbol)
.Where(s => !s.IsStatic)
.FilterToVisibleAndBrowsableSymbols(options.GetOption(CompletionOptions.HideAdvancedMembers, semanticModel.Language), semanticModel.Compilation);
// We're going to create a entry for each one, including the signature
var namePosition = name.SpanStart;
var text = await syntaxTree.GetTextAsync(cancellationToken).ConfigureAwait(false);
var textChangeSpan = CompletionUtilities.GetTextChangeSpan(text, position);
foreach (var member in members)
{
var displayText = member.ToMinimalDisplayString(semanticModel, namePosition, s_signatureDisplayFormat);
var insertionText = displayText;
context.AddItem(new SymbolCompletionItem(
this,
displayText,
insertionText: insertionText,
filterSpan: textChangeSpan,
position: position,
symbols: new List <ISymbol> {
member
},
context: CSharpSyntaxContext.CreateContext(document.Project.Solution.Workspace, semanticModel, position, cancellationToken),
rules: ItemRules.Instance));
}
}
private static bool IsAfterCompleteExpressionOrPatternInCaseLabel(CSharpSyntaxContext context,
out SyntaxNodeOrToken nodeOrToken)
{
nodeOrToken = null;
var switchLabel = context.TargetToken.GetAncestor <SwitchLabelSyntax>();
if (switchLabel == null)
{
return(false);
}
var expressionOrPattern = switchLabel.ChildNodes().FirstOrDefault();
if (expressionOrPattern == null)
{
// It must have been a default label.
return(false);
}
// If the last token is missing, the expression is incomplete - possibly because of missing parentheses,
// but not necessarily. We don't want to offer 'when' in those cases. Here are some examples that illustrate this:
// case |
// case x.|
// case 1 + |
// case (1 + 1 |
// Also note that if there's a missing token inside the expression, that's fine and we do offer 'when':
// case (1 + ) |
if (expressionOrPattern.GetLastToken(includeZeroWidth: true).IsMissing)
{
return(false);
}
// There are zero width tokens that are not "missing" (inserted by the parser) because they are optional,
// such as the identifier in a recursive pattern. We want to ignore those now, so we exclude all zero width.
var lastToken = expressionOrPattern.GetLastToken(includeZeroWidth: false);
if (lastToken == context.TargetToken)
{
nodeOrToken = expressionOrPattern;
return(true);
}
if (lastToken == context.LeftToken)
{
// The user is typing a new word (might be a partially written 'when' keyword),
// which is part of the pattern as opposed to appearing outside of it. In a few special cases,
// this word can actually be replaced with 'when' and the resulting pattern would still be valid.
if (expressionOrPattern is DeclarationPatternSyntax declarationPattern)
{
// The new token causes this to be parsed as a declaration pattern:
// case constant w| ('w' = LeftToken, 'constant' = TargetToken)
// However 'constant' itself might end up being a valid constant pattern.
// We will pretend as if 'w' didn't exist so that the later check
// for whether 'constant' is actually a type can still work properly.
nodeOrToken = declarationPattern.Type;
return(true);
}
if (expressionOrPattern is VarPatternSyntax varPattern)
{
// The new token causes this to be parsed as a var pattern:
// case var w| ('w' = LeftToken, 'var' = TargetToken)
// However 'var' itself might end up being a valid constant pattern.
nodeOrToken = varPattern.VarKeyword;
return(true);
}
if (expressionOrPattern is RecursivePatternSyntax recursivePattern)
{
// The new token is consumed as the identifier in a recursive pattern:
// case { } w| ('w' = LeftToken, '}' = TargetToken)
// However the identifier is optional and can be replaced by 'when'.
nodeOrToken = recursivePattern.Type;
return(true);
}
// In other cases, this would not be true because the pattern would be incomplete without this word:
// case 1 + w|
}
return(false);
}
static async Task<IEnumerable<ISymbol>> GetPreselectedSymbolsWorker (CSharpSyntaxContext context, ITypeSymbol inferredType, int position, CancellationToken cancellationToken)
{
var result = await GetPreselectedSymbolsWorker2 (context, inferredType, cancellationToken).ConfigureAwait (false);
if (result.Any ()) {
var type = (ITypeSymbol)result.Single ();
var alias = await type.FindApplicableAlias (position, context.SemanticModel, cancellationToken).ConfigureAwait (false);
if (alias != null) {
return SpecializedCollections.SingletonEnumerable (alias);
}
}
return result;
}
public static bool IsMemberDeclarationContext(
this SyntaxTree syntaxTree,
int position,
CSharpSyntaxContext contextOpt,
ISet<SyntaxKind> validModifiers,
ISet<SyntaxKind> validTypeDeclarations,
bool canBePartial,
CancellationToken cancellationToken)
{
var typeDecl = contextOpt != null
? contextOpt.ContainingTypeOrEnumDeclaration
: syntaxTree.GetContainingTypeOrEnumDeclaration(position, cancellationToken);
if (typeDecl == null)
{
return false;
}
if (!validTypeDeclarations.Contains(typeDecl.Kind()))
{
return false;
}
validTypeDeclarations = validTypeDeclarations ?? SpecializedCollections.EmptySet<SyntaxKind>();
// Check many of the simple cases first.
var leftToken = contextOpt != null
? contextOpt.LeftToken
: syntaxTree.FindTokenOnLeftOfPosition(position, cancellationToken);
if (syntaxTree.IsMemberDeclarationContext(position, leftToken, cancellationToken))
{
return true;
}
var token = contextOpt != null
? contextOpt.TargetToken
: leftToken.GetPreviousTokenIfTouchingWord(position);
// A member can also show up after certain types of modifiers
if (canBePartial &&
token.IsKindOrHasMatchingText(SyntaxKind.PartialKeyword))
{
return true;
}
var modifierTokens = contextOpt != null
? contextOpt.PrecedingModifiers
: syntaxTree.GetPrecedingModifiers(position, leftToken, cancellationToken);
if (!modifierTokens.Any())
{
return false;
}
validModifiers = validModifiers ?? SpecializedCollections.EmptySet<SyntaxKind>();
if (modifierTokens.IsSubsetOf(validModifiers))
{
var member = token.Parent;
if (token.HasMatchingText(SyntaxKind.AsyncKeyword))
{
// second appearance of "async", not followed by modifier: treat it as type
if (syntaxTree.GetPrecedingModifiers(token.SpanStart, token, cancellationToken).Any(x => x == SyntaxKind.AsyncKeyword))
{
return false;
}
// rule out async lambdas inside a method
if (token.GetAncestor<StatementSyntax>() == null)
{
member = token.GetAncestor<MemberDeclarationSyntax>();
}
}
// cases:
// public |
// async |
// public async |
return member != null &&
member.Parent is BaseTypeDeclarationSyntax;
}
return false;
}
protected override async Task <SyntaxContext> CreateContext(Document document, int position, CancellationToken cancellationToken)
{
var semanticModel = await document.GetSemanticModelForSpanAsync(new TextSpan(position, 0), cancellationToken).ConfigureAwait(false);
return(CSharpSyntaxContext.CreateContext(document.Project.Solution.Workspace, semanticModel, position, cancellationToken));
}
protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken)
{
return
(context.IsStatementContext ||
context.IsGlobalStatementContext);
}
protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken)
{
return(context.IsCatchFilterContext ||
(IsAfterCompleteExpressionOrPatternInCaseLabel(context, out var expressionOrPattern) &&
!IsTypeName(expressionOrPattern, context.SemanticModel, cancellationToken)));
}
protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken)
{
return(context.IsMemberAttributeContext(s_validTypeDeclarations, cancellationToken));
}
private bool IsAttributeArgumentContext(CSharpSyntaxContext context)
{
return
(context.IsAnyExpressionContext &&
context.LeftToken.GetAncestor <AttributeSyntax>() != null);
}
private static bool IsUnsafeDefaultExpressionContext(CSharpSyntaxContext context)
{
return
(context.TargetToken.IsUnsafeContext() &&
context.SyntaxTree.IsDefaultExpressionContext(context.Position, context.LeftToken));
}
protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken)
{
var syntaxTree = context.SyntaxTree;
// namespaces are illegal in interactive code:
if (syntaxTree.IsScript())
{
return(false);
}
// cases:
// root: |
// root: n|
// extern alias a;
// |
// extern alias a;
// n|
// using Foo;
// |
// using Foo;
// n|
// using Foo = Bar;
// |
// using Foo = Bar;
// n|
// namespace N {}
// |
// namespace N {}
// n|
// class C {}
// |
// class C {}
// n|
var leftToken = context.LeftToken;
var token = context.TargetToken;
// root: n|
// ns Foo { n|
// extern alias a;
// n|
// using Foo;
// n|
// using Foo = Bar;
// n|
// a namespace can't come before usings/externs
// a child namespace can't come before usings/externs
if (leftToken.GetNextToken(includeSkipped: true).IsUsingOrExternKeyword())
{
return(false);
}
// root: |
if (token.Kind() == SyntaxKind.None)
{
// root namespace
var root = syntaxTree.GetRoot(cancellationToken) as CompilationUnitSyntax;
if (root.Externs.Count > 0 ||
root.Usings.Count > 0)
{
return(false);
}
return(true);
}
if (token.Kind() == SyntaxKind.OpenBraceToken &&
token.Parent.IsKind(SyntaxKind.NamespaceDeclaration))
{
return(true);
}
// extern alias a;
// |
// using Foo;
// |
if (token.Kind() == SyntaxKind.SemicolonToken)
{
if (token.Parent.IsKind(SyntaxKind.ExternAliasDirective, SyntaxKind.UsingDirective))
{
return(true);
}
}
// class C {}
// |
if (token.Kind() == SyntaxKind.CloseBraceToken)
{
if (token.Parent is TypeDeclarationSyntax &&
!(token.Parent.GetParent() is TypeDeclarationSyntax))
{
return(true);
}
else if (token.Parent.IsKind(SyntaxKind.NamespaceDeclaration))
{
return(true);
}
}
// delegate void D();
// |
if (token.Kind() == SyntaxKind.SemicolonToken)
{
if (token.Parent.IsKind(SyntaxKind.DelegateDeclaration) &&
!(token.Parent.GetParent() is TypeDeclarationSyntax))
{
return(true);
}
}
// [assembly: foo]
// |
if (token.Kind() == SyntaxKind.CloseBracketToken &&
token.Parent.IsKind(SyntaxKind.AttributeList) &&
token.Parent.IsParentKind(SyntaxKind.CompilationUnit))
{
return(true);
}
return(false);
}
private static ImmutableArray <ISymbol> GetSymbolsForNamespaceDeclarationNameContext(CSharpSyntaxContext context, CancellationToken cancellationToken)
{
var declarationSyntax = context.TargetToken.GetAncestor <NamespaceDeclarationSyntax>();
if (declarationSyntax == null)
{
return(ImmutableArray <ISymbol> .Empty);
}
return(GetRecommendedNamespaceNameSymbols(context.SemanticModel, declarationSyntax, cancellationToken));
}
protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken)
{
return
(IsUnsafeStatementContext(context) ||
IsMemberDeclarationContext(context, cancellationToken));
}
private static ImmutableArray <ISymbol> GetSymbolsOffOfBoundExpression(
CSharpSyntaxContext context,
ExpressionSyntax originalExpression,
ExpressionSyntax expression,
SymbolInfo leftHandBinding,
INamespaceOrTypeSymbol container,
CancellationToken cancellationToken)
{
var useBaseReferenceAccessibility = false;
var excludeInstance = false;
var excludeStatic = false;
var symbol = leftHandBinding.GetBestOrAllSymbols().FirstOrDefault();
if (symbol != null)
{
// If the thing on the left is a type, namespace or alias and the original
// expression was parenthesized, we shouldn't show anything in IntelliSense.
if (originalExpression.IsKind(SyntaxKind.ParenthesizedExpression) &&
symbol.MatchesKind(SymbolKind.NamedType,
SymbolKind.Namespace,
SymbolKind.Alias))
{
return(ImmutableArray <ISymbol> .Empty);
}
// If the thing on the left is a lambda expression, we shouldn't show anything.
if (symbol.Kind == SymbolKind.Method &&
((IMethodSymbol)symbol).MethodKind == MethodKind.AnonymousFunction)
{
return(ImmutableArray <ISymbol> .Empty);
}
// If the thing on the left is an event that can't be used as a field, we shouldn't show anything
if (symbol.Kind == SymbolKind.Event &&
!context.SemanticModel.IsEventUsableAsField(originalExpression.SpanStart, (IEventSymbol)symbol))
{
return(ImmutableArray <ISymbol> .Empty);
}
// If the thing on the left is a this parameter (e.g. this or base) and we're in a static context,
// we shouldn't show anything
if (symbol.IsThisParameter() &&
expression.IsInStaticContext())
{
return(ImmutableArray <ISymbol> .Empty);
}
// What is the thing on the left?
switch (symbol.Kind)
{
case SymbolKind.NamedType:
case SymbolKind.Namespace:
excludeInstance = true;
container = (INamespaceOrTypeSymbol)symbol;
break;
case SymbolKind.Alias:
excludeInstance = true;
container = ((IAliasSymbol)symbol).Target;
break;
case SymbolKind.Parameter:
var parameter = (IParameterSymbol)symbol;
excludeStatic = true;
// case:
// base.|
if (parameter.IsThis && !object.Equals(parameter.Type, container))
{
useBaseReferenceAccessibility = true;
}
break;
default:
excludeStatic = true;
break;
}
}
else if (container != null)
{
excludeStatic = true;
}
else
{
return(ImmutableArray <ISymbol> .Empty);
}
Debug.Assert(!excludeInstance || !excludeStatic);
Debug.Assert(!excludeInstance || !useBaseReferenceAccessibility);
// nameof(X.|
// Show static and instance members.
if (context.IsNameOfContext)
{
excludeInstance = false;
excludeStatic = false;
}
var position = originalExpression.SpanStart;
var symbols = useBaseReferenceAccessibility
? context.SemanticModel.LookupBaseMembers(position)
: excludeInstance
? context.SemanticModel.LookupStaticMembers(position, container)
: SuppressDefaultTupleElements(container,
context.SemanticModel.LookupSymbols(position, container, includeReducedExtensionMethods: true));
// If we're showing instance members, don't include nested types
return(excludeStatic
? symbols.WhereAsArray(s => !s.IsStatic && !(s is ITypeSymbol))
: symbols);
}
private static bool IsUnsafeStatementContext(CSharpSyntaxContext context)
{
return
(context.TargetToken.IsUnsafeContext() &&
context.IsStatementContext);
}
protected override bool IsValidContext(
int position,
CSharpSyntaxContext context,
CancellationToken cancellationToken
) => context.IsPreProcessorKeywordContext;
internal async Task <IEnumerable <RecommendedKeyword> > RecommendKeywordsAsync(int position, CSharpSyntaxContext context)
{
var syntaxKind = await _recommender.RecommendKeywordAsync(position, context, CancellationToken.None).ConfigureAwait(false);
if (syntaxKind.HasValue)
{
var matchPriority = _recommender.ShouldPreselect(context, CancellationToken.None) ? SymbolMatchPriority.Keyword : MatchPriority.Default;
return(SpecializedCollections.SingletonEnumerable(
new RecommendedKeyword(SyntaxFacts.GetText(syntaxKind.Value), matchPriority: matchPriority)));
}
return(null);
}
static Task<IEnumerable<ISymbol>> GetPreselectedSymbolsWorker2 (CSharpSyntaxContext context, ITypeSymbol type, CancellationToken cancellationToken)
{
// Unwrap an array type fully. We only want to offer the underlying element type in the
// list of completion items.
bool isArray = false;
while (type is IArrayTypeSymbol) {
isArray = true;
type = ((IArrayTypeSymbol)type).ElementType;
}
if (type == null) {
return Task.FromResult (Enumerable.Empty<ISymbol> ());
}
// Unwrap nullable
if (type.OriginalDefinition.SpecialType == SpecialType.System_Nullable_T) {
type = type.GetTypeArguments ().FirstOrDefault ();
}
if (type.SpecialType == SpecialType.System_Void) {
return Task.FromResult (Enumerable.Empty<ISymbol> ());
}
if (type.ContainsAnonymousType ()) {
return Task.FromResult (Enumerable.Empty<ISymbol> ());
}
if (!type.CanBeReferencedByName) {
return Task.FromResult (Enumerable.Empty<ISymbol> ());
}
// Normally the user can't say things like "new IList". Except for "IList[] x = new |".
// In this case we do want to allow them to preselect certain types in the completion
// list even if they can't new them directly.
if (!isArray) {
if (type.TypeKind == TypeKind.Interface ||
type.TypeKind == TypeKind.Pointer ||
type.TypeKind == TypeKind.Dynamic ||
type.IsAbstract) {
return Task.FromResult (Enumerable.Empty<ISymbol> ());
}
if (type.TypeKind == TypeKind.TypeParameter &&
!((ITypeParameterSymbol)type).HasConstructorConstraint) {
return Task.FromResult (Enumerable.Empty<ISymbol> ());
}
}
// if (!type.IsEditorBrowsable(options.GetOption(RecommendationOptions.HideAdvancedMembers, context.SemanticModel.Language), context.SemanticModel.Compilation))
// {
// return SpecializedTasks.EmptyEnumerable<ISymbol>();
// }
//
return Task.FromResult (SpecializedCollections.SingletonEnumerable ((ISymbol)type));
}
protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken) => context.SyntaxTree.IsValidContextForJoinClause(position, context.LeftToken);
protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken)
{
var syntaxTree = context.SyntaxTree;
return(syntaxTree.IsCatchOrFinallyContext(position, context.LeftToken, cancellationToken));
}
protected override Task <SyntaxContext> CreateSyntaxContextAsync(Document document, SemanticModel semanticModel, int position, CancellationToken cancellationToken)
{
return(Task.FromResult <SyntaxContext>(CSharpSyntaxContext.CreateContext(document.Project.Solution.Workspace, semanticModel, position, cancellationToken)));
}
public static bool IsTypeDeclarationContext(
this SyntaxTree syntaxTree,
int position,
CSharpSyntaxContext contextOpt,
ISet<SyntaxKind> validModifiers,
ISet<SyntaxKind> validTypeDeclarations,
bool canBePartial,
CancellationToken cancellationToken)
{
// We only allow nested types inside a class or struct, not inside a
// an interface or enum.
var typeDecl = contextOpt != null
? contextOpt.ContainingTypeDeclaration
: syntaxTree.GetContainingTypeDeclaration(position, cancellationToken);
validTypeDeclarations = validTypeDeclarations ?? SpecializedCollections.EmptySet<SyntaxKind>();
if (typeDecl != null)
{
if (!validTypeDeclarations.Contains(typeDecl.Kind()))
{
return false;
}
}
// Check many of the simple cases first.
var leftToken = contextOpt != null
? contextOpt.LeftToken
: syntaxTree.FindTokenOnLeftOfPosition(position, cancellationToken);
if (syntaxTree.IsTypeDeclarationContext(position, leftToken, cancellationToken))
{
return true;
}
// If we're touching the right of an identifier, move back to
// previous token.
var token = contextOpt != null
? contextOpt.TargetToken
: leftToken.GetPreviousTokenIfTouchingWord(position);
// A type can also show up after certain types of modifiers
if (canBePartial &&
token.IsKindOrHasMatchingText(SyntaxKind.PartialKeyword))
{
return true;
}
// using static | is never a type declaration context
if (token.IsStaticKeywordInUsingDirective())
{
return false;
}
var modifierTokens = contextOpt != null
? contextOpt.PrecedingModifiers
: syntaxTree.GetPrecedingModifiers(position, leftToken, cancellationToken);
if (!modifierTokens.Any())
{
return false;
}
validModifiers = validModifiers ?? SpecializedCollections.EmptySet<SyntaxKind>();
if (modifierTokens.IsProperSubsetOf(validModifiers))
{
// the parent is the member
// the grandparent is the container of the member
var container = token.Parent.GetParent();
if (container.IsKind(SyntaxKind.CompilationUnit) ||
container.IsKind(SyntaxKind.NamespaceDeclaration) ||
container.IsKind(SyntaxKind.ClassDeclaration) ||
container.IsKind(SyntaxKind.StructDeclaration))
{
return true;
}
}
return false;
}
protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken)
{
return(context.TargetToken.IsOrderByDirectionContext());
}