/
SyntaxFacts.cs
488 lines (406 loc) · 18.6 KB
/
SyntaxFacts.cs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
// Copyright (c) Microsoft. All Rights Reserved. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using Microsoft.CodeAnalysis.CSharp.Symbols;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Roslyn.Utilities;
using static Microsoft.CodeAnalysis.CSharp.SyntaxKind;
namespace Microsoft.CodeAnalysis.CSharp
{
public static partial class SyntaxFacts
{
/// <summary>
/// Returns true if the node is the alias of an AliasQualifiedNameSyntax
/// </summary>
public static bool IsAliasQualifier(SyntaxNode node)
{
var p = node.Parent as AliasQualifiedNameSyntax;
return p != null && p.Alias == node;
}
public static bool IsAttributeName(SyntaxNode node)
{
var parent = node.Parent;
if (parent == null || !IsName(node.Kind()))
{
return false;
}
switch (parent.Kind())
{
case QualifiedName:
var qn = (QualifiedNameSyntax)parent;
return qn.Right == node ? IsAttributeName(parent) : false;
case AliasQualifiedName:
var an = (AliasQualifiedNameSyntax)parent;
return an.Name == node ? IsAttributeName(parent) : false;
}
var p = node.Parent as AttributeSyntax;
return p != null && p.Name == node;
}
/// <summary>
/// Returns true if the node is the object of an invocation expression.
/// </summary>
public static bool IsInvoked(ExpressionSyntax node)
{
node = (ExpressionSyntax)SyntaxFactory.GetStandaloneExpression(node);
var inv = node.Parent as InvocationExpressionSyntax;
return inv != null && inv.Expression == node;
}
/// <summary>
/// Returns true if the node is the object of an element access expression.
/// </summary>
public static bool IsIndexed(ExpressionSyntax node)
{
node = (ExpressionSyntax)SyntaxFactory.GetStandaloneExpression(node);
var indexer = node.Parent as ElementAccessExpressionSyntax;
return indexer != null && indexer.Expression == node;
}
public static bool IsNamespaceAliasQualifier(ExpressionSyntax node)
{
var parent = node.Parent as AliasQualifiedNameSyntax;
return parent != null && parent.Alias == node;
}
/// <summary>
/// Returns true if the node is in a tree location that is expected to be a type
/// </summary>
/// <param name="node"></param>
/// <returns></returns>
public static bool IsInTypeOnlyContext(ExpressionSyntax node)
{
node = SyntaxFactory.GetStandaloneExpression(node);
var parent = node.Parent;
if (parent != null)
{
switch (parent.Kind())
{
case Attribute:
return ((AttributeSyntax)parent).Name == node;
case ArrayType:
return ((ArrayTypeSyntax)parent).ElementType == node;
case PointerType:
return ((PointerTypeSyntax)parent).ElementType == node;
case PredefinedType:
return true;
case NullableType:
return ((NullableTypeSyntax)parent).ElementType == node;
case TypeArgumentList:
// all children of GenericNames are type arguments
return true;
case CastExpression:
return ((CastExpressionSyntax)parent).Type == node;
case ObjectCreationExpression:
return ((ObjectCreationExpressionSyntax)parent).Type == node;
case StackAllocArrayCreationExpression:
return ((StackAllocArrayCreationExpressionSyntax)parent).Type == node;
case FromClause:
return ((FromClauseSyntax)parent).Type == node;
case JoinClause:
return ((JoinClauseSyntax)parent).Type == node;
case VariableDeclaration:
return ((VariableDeclarationSyntax)parent).Type == node;
case ForEachStatement:
return ((ForEachStatementSyntax)parent).Type == node;
case CatchDeclaration:
return ((CatchDeclarationSyntax)parent).Type == node;
case AsExpression:
case IsExpression:
return ((BinaryExpressionSyntax)parent).Right == node;
case TypeOfExpression:
return ((TypeOfExpressionSyntax)parent).Type == node;
case SizeOfExpression:
return ((SizeOfExpressionSyntax)parent).Type == node;
case DefaultExpression:
return ((DefaultExpressionSyntax)parent).Type == node;
case RefValueExpression:
return ((RefValueExpressionSyntax)parent).Type == node;
case RefType:
return ((RefTypeSyntax)parent).Type == node;
case Parameter:
return ((ParameterSyntax)parent).Type == node;
case TypeConstraint:
return ((TypeConstraintSyntax)parent).Type == node;
case MethodDeclaration:
return ((MethodDeclarationSyntax)parent).ReturnType == node;
case IndexerDeclaration:
return ((IndexerDeclarationSyntax)parent).Type == node;
case OperatorDeclaration:
return ((OperatorDeclarationSyntax)parent).ReturnType == node;
case ConversionOperatorDeclaration:
return ((ConversionOperatorDeclarationSyntax)parent).Type == node;
case PropertyDeclaration:
return ((PropertyDeclarationSyntax)parent).Type == node;
case DelegateDeclaration:
return ((DelegateDeclarationSyntax)parent).ReturnType == node;
case EventDeclaration:
return ((EventDeclarationSyntax)parent).Type == node;
case LocalFunctionStatement:
return ((LocalFunctionStatementSyntax)parent).ReturnType == node;
case SimpleBaseType:
return true;
case CrefParameter:
return true;
case ConversionOperatorMemberCref:
return ((ConversionOperatorMemberCrefSyntax)parent).Type == node;
case ExplicitInterfaceSpecifier:
// #13.4.1 An explicit member implementation is a method, property, event or indexer
// declaration that references a fully qualified interface member name.
// A ExplicitInterfaceSpecifier represents the left part (QN) of the member name, so it
// should be treated like a QualifiedName.
return ((ExplicitInterfaceSpecifierSyntax)parent).Name == node;
case DeclarationPattern:
return ((DeclarationPatternSyntax)parent).Type == node;
case TupleElement:
return ((TupleElementSyntax)parent).Type == node;
case DeclarationExpression:
return ((DeclarationExpressionSyntax)parent).Type == node;
case IncompleteMember:
return ((IncompleteMemberSyntax)parent).Type == node;
}
}
return false;
}
/// <summary>
/// Returns true if a node is in a tree location that is expected to be either a namespace or type
/// </summary>
/// <param name="node"></param>
/// <returns></returns>
public static bool IsInNamespaceOrTypeContext(ExpressionSyntax node)
{
if (node != null)
{
node = (ExpressionSyntax)SyntaxFactory.GetStandaloneExpression(node);
var parent = node.Parent;
if (parent != null)
{
switch (parent.Kind())
{
case UsingDirective:
return ((UsingDirectiveSyntax)parent).Name == node;
case QualifiedName:
// left of QN is namespace or type. Note: when you have "a.b.c()", then
// "a.b" is not a qualified name, it is a member access expression.
// Qualified names are only parsed when the parser knows it's a type only
// context.
return ((QualifiedNameSyntax)parent).Left == node;
default:
return IsInTypeOnlyContext(node);
}
}
}
return false;
}
/// <summary>
/// Is the node the name of a named argument of an invocation, object creation expression,
/// constructor initializer, or element access, but not an attribute.
/// </summary>
public static bool IsNamedArgumentName(SyntaxNode node)
{
// An argument name is an IdentifierName inside a NameColon, inside an Argument, inside an ArgumentList, inside an
// Invocation, ObjectCreation, ObjectInitializer, ElementAccess or Subpattern.
if (!node.IsKind(IdentifierName))
{
return false;
}
var parent1 = node.Parent;
if (parent1 == null || !parent1.IsKind(NameColon))
{
return false;
}
var parent2 = parent1.Parent;
if (parent2.IsKind(SyntaxKind.Subpattern))
{
return true;
}
if (parent2 == null || !(parent2.IsKind(Argument) || parent2.IsKind(AttributeArgument)))
{
return false;
}
var parent3 = parent2.Parent;
if (parent3 == null)
{
return false;
}
if (parent3.IsKind(SyntaxKind.TupleExpression))
{
return true;
}
if (!(parent3 is BaseArgumentListSyntax || parent3.IsKind(AttributeArgumentList)))
{
return false;
}
var parent4 = parent3.Parent;
if (parent4 == null)
{
return false;
}
switch (parent4.Kind())
{
case InvocationExpression:
case TupleExpression:
case ObjectCreationExpression:
case ObjectInitializerExpression:
case ElementAccessExpression:
case Attribute:
case BaseConstructorInitializer:
case ThisConstructorInitializer:
return true;
default:
return false;
}
}
/// <summary>
/// Is the expression the initializer in a fixed statement?
/// </summary>
public static bool IsFixedStatementExpression(SyntaxNode node)
{
node = node.Parent;
// Dig through parens because dev10 does (even though the spec doesn't say so)
// Dig through casts because there's a special error code (CS0254) for such casts.
while (node != null && (node.IsKind(ParenthesizedExpression) || node.IsKind(CastExpression))) node = node.Parent;
if (node == null || !node.IsKind(EqualsValueClause)) return false;
node = node.Parent;
if (node == null || !node.IsKind(VariableDeclarator)) return false;
node = node.Parent;
if (node == null || !node.IsKind(VariableDeclaration)) return false;
node = node.Parent;
return node != null && node.IsKind(FixedStatement);
}
public static string GetText(Accessibility accessibility)
{
switch (accessibility)
{
case Accessibility.NotApplicable:
return string.Empty;
case Accessibility.Private:
return SyntaxFacts.GetText(PrivateKeyword);
case Accessibility.ProtectedAndInternal:
return SyntaxFacts.GetText(PrivateKeyword) + " " + SyntaxFacts.GetText(ProtectedKeyword);
case Accessibility.Internal:
return SyntaxFacts.GetText(InternalKeyword);
case Accessibility.Protected:
return SyntaxFacts.GetText(ProtectedKeyword);
case Accessibility.ProtectedOrInternal:
return SyntaxFacts.GetText(ProtectedKeyword) + " " + SyntaxFacts.GetText(InternalKeyword);
case Accessibility.Public:
return SyntaxFacts.GetText(PublicKeyword);
default:
throw ExceptionUtilities.UnexpectedValue(accessibility);
}
}
internal static bool IsStatementExpression(SyntaxNode syntax)
{
// The grammar gives:
//
// expression-statement:
// statement-expression ;
//
// statement-expression:
// invocation-expression
// object-creation-expression
// assignment
// post-increment-expression
// post-decrement-expression
// pre-increment-expression
// pre-decrement-expression
// await-expression
switch (syntax.Kind())
{
case InvocationExpression:
case ObjectCreationExpression:
case SimpleAssignmentExpression:
case AddAssignmentExpression:
case SubtractAssignmentExpression:
case MultiplyAssignmentExpression:
case DivideAssignmentExpression:
case ModuloAssignmentExpression:
case AndAssignmentExpression:
case OrAssignmentExpression:
case ExclusiveOrAssignmentExpression:
case LeftShiftAssignmentExpression:
case RightShiftAssignmentExpression:
case CoalesceAssignmentExpression:
case PostIncrementExpression:
case PostDecrementExpression:
case PreIncrementExpression:
case PreDecrementExpression:
case AwaitExpression:
return true;
case ConditionalAccessExpression:
var access = (ConditionalAccessExpressionSyntax)syntax;
return IsStatementExpression(access.WhenNotNull);
// Allow missing IdentifierNames; they will show up in error cases
// where there is no statement whatsoever.
case IdentifierName:
return syntax.IsMissing;
default:
return false;
}
}
[System.Obsolete("IsLambdaBody API is obsolete", true)]
public static bool IsLambdaBody(SyntaxNode node)
{
return LambdaUtilities.IsLambdaBody(node);
}
internal static bool IsIdentifierVar(this Syntax.InternalSyntax.SyntaxToken node)
{
return node.ContextualKind == SyntaxKind.VarKeyword;
}
internal static bool IsIdentifierVarOrPredefinedType(this Syntax.InternalSyntax.SyntaxToken node)
{
return node.IsIdentifierVar() || IsPredefinedType(node.Kind);
}
internal static bool IsDeclarationExpressionType(SyntaxNode node, out DeclarationExpressionSyntax parent)
{
parent = node.Parent as DeclarationExpressionSyntax;
return node == parent?.Type;
}
/// <summary>
/// Given an initializer expression infer the name of anonymous property or tuple element.
/// Returns null if unsuccessful
/// </summary>
public static string TryGetInferredMemberName(this SyntaxNode syntax)
{
SyntaxToken nameToken;
switch (syntax.Kind())
{
case SyntaxKind.SingleVariableDesignation:
nameToken = ((SingleVariableDesignationSyntax)syntax).Identifier;
break;
case SyntaxKind.DeclarationExpression:
var declaration = (DeclarationExpressionSyntax)syntax;
var designationKind = declaration.Designation.Kind();
if (designationKind == SyntaxKind.ParenthesizedVariableDesignation ||
designationKind == SyntaxKind.DiscardDesignation)
{
return null;
}
nameToken = ((SingleVariableDesignationSyntax)declaration.Designation).Identifier;
break;
case SyntaxKind.ParenthesizedVariableDesignation:
case SyntaxKind.DiscardDesignation:
return null;
default:
if (syntax is ExpressionSyntax expr)
{
nameToken = expr.ExtractAnonymousTypeMemberName();
break;
}
return null;
}
return nameToken.ValueText;
}
/// <summary>
/// Checks whether the element name is reserved.
///
/// For example:
/// "Item3" is reserved (at certain positions).
/// "Rest", "ToString" and other members of System.ValueTuple are reserved (in any position).
/// Names that are not reserved return false.
/// </summary>
public static bool IsReservedTupleElementName(string elementName)
{
return TupleTypeSymbol.IsElementNameReserved(elementName) != -1;
}
internal static bool HasAnyBody(this BaseMethodDeclarationSyntax declaration)
{
return (declaration.Body ?? (SyntaxNode)declaration.ExpressionBody) != null;
}
}
}