Detailed table of contents

Foreword
Introduction
§1 Scope
§2 Normative references
§3 Terms and definitions
§4 General description
§5 Conformance
§6 Lexical structure
- §6.1 Programs
- §6.2 Grammars
  - §6.2.1 General
  - §6.2.2 Grammar notation
  - §6.2.3 Lexical grammar
  - §6.2.4 Syntactic grammar
  - §6.2.5 Grammar ambiguities
- §6.3 Lexical analysis
  - §6.3.1 General
  - §6.3.2 Line terminators
  - §6.3.3 Comments
  - §6.3.4 White space
- §6.4 Tokens
  - §6.4.1 General
  - §6.4.2 Unicode character escape sequences
  - §6.4.3 Identifiers
  - §6.4.4 Keywords
  - §6.4.5 Literals
    - §6.4.5.1 General
    - §6.4.5.2 Boolean literals
    - §6.4.5.3 Integer literals
    - §6.4.5.4 Real literals
    - §6.4.5.5 Character literals
    - §6.4.5.6 String literals
    - §6.4.5.7 The null literal
  - §6.4.6 Operators and punctuators
- §6.5 Pre-processing directives
  - §6.5.1 General
  - §6.5.2 Conditional compilation symbols
  - §6.5.3 Pre-processing expressions
  - §6.5.4 Definition directives
  - §6.5.5 Conditional compilation directives
  - §6.5.6 Diagnostic directives
  - §6.5.7 Region directives
  - §6.5.8 Line directives
  - §6.5.9 Nullable directive
  - §6.5.10 Pragma directives
§7 Basic concepts
- §7.1 Application startup and termination
  - §7.1.1 General
  - §7.1.2 Named entry points
  - §7.1.3 Using top-level statements
  - §7.1.4 Externally defined entry point
  - §7.1.5 Entry point selection
  - §7.1.6 Entry point invocation
- §7.2 Declarations
- §7.3 Members
  - §7.3.1 General
  - §7.3.2 Namespace members
  - §7.3.3 Struct members
  - §7.3.4 Enumeration members
  - §7.3.5 Class members
  - §7.3.6 Interface members
  - §7.3.7 Array members
  - §7.3.8 Delegate members
- §7.4 Member access
  - §7.4.1 General
  - §7.4.2 Declared accessibility
  - §7.4.3 Accessibility domains
  - §7.4.4 Protected access
  - §7.4.5 Accessibility constraints
- §7.5 Signatures and overloading
- §7.6 Scopes
  - §7.6.1 General
  - §7.6.2 Name hiding
    - §7.6.2.1 General
    - §7.6.2.2 Hiding through nesting
    - §7.6.2.3 Hiding through inheritance
- §7.7 Namespace and type names
  - §7.7.1 General
  - §7.7.2 Unqualified names
  - §7.7.3 Fully qualified names
- §7.8 Automatic memory management
- §7.9 Execution order
§8 Types
- §8.1 General
- §8.2 Reference types
  - §8.2.1 General
  - §8.2.2 Class types
  - §8.2.3 The object type
  - §8.2.4 The dynamic type
  - §8.2.5 The string type
  - §8.2.6 Interface types
  - §8.2.7 Array types
  - §8.2.8 Delegate types
- §8.3 Value types
  - §8.3.1 General
  - §8.3.2 The System.ValueType type
  - §8.3.3 Default constructors
  - §8.3.4 Struct types
  - §8.3.5 Simple types
  - §8.3.6 Integral types
  - §8.3.7 Floating-point types
  - §8.3.8 The Decimal type
  - §8.3.9 The Bool type
  - §8.3.10 Enumeration types
  - §8.3.11 Tuple types
    - §8.3.11.1 General
    - §8.3.11.2 Eliding intermediate tuple creation
    - §8.3.11.3 Runtime representation
  - §8.3.12 Nullable value types
  - §8.3.13 Boxing and unboxing
- §8.4 Constructed types
  - §8.4.1 General
  - §8.4.2 Type arguments
  - §8.4.3 Open and closed types
  - §8.4.4 Bound and unbound types
  - §8.4.5 Satisfying constraints
- §8.5 Type parameters
- §8.6 Expression tree types
- §8.7 The dynamic type
- §8.8 Unmanaged types
- §8.9 Reference Types and nullability
  - §8.9.1 General
  - §8.9.2 Non-nullable reference types
  - §8.9.3 Nullable reference types
  - §8.9.4 Nullable context
    - §8.9.4.1 General
    - §8.9.4.2 Nullable disable
    - §8.9.4.3 Nullable annotations
    - §8.9.4.4 Nullable warnings
    - §8.9.4.5 Nullable enable
  - §8.9.5 Nullabilities and null states
    - §8.9.5.1 General
    - §8.9.5.2 Flow analysis
    - §8.9.5.3 Type conversions
§9 Variables
- §9.1 General
- §9.2 Variable categories
  - §9.2.1 General
  - §9.2.2 Static variables
  - §9.2.3 Instance variables
    - §9.2.3.1 General
    - §9.2.3.2 Instance variables in classes
    - §9.2.3.3 Instance variables in structs
  - §9.2.4 Array elements
  - §9.2.5 Value parameters
  - §9.2.6 Reference parameters
  - §9.2.7 Output parameters
  - §9.2.8 Input parameters
  - §9.2.9 Local variables
    - §9.2.9.1 General
    - §9.2.9.2 Discards
- §9.3 Default values
- §9.4 Definite assignment
  - §9.4.1 General
  - §9.4.2 Initially assigned variables
  - §9.4.3 Initially unassigned variables
  - §9.4.4 Precise rules for determining definite assignment
    - §9.4.4.1 General
    - §9.4.4.2 General rules for statements
    - §9.4.4.3 Block statements, checked, and unchecked statements
    - §9.4.4.4 Expression statements
    - §9.4.4.5 Declaration statements
    - §9.4.4.6 If statements
    - §9.4.4.7 Switch statements
    - §9.4.4.8 While statements
    - §9.4.4.9 Do statements
    - §9.4.4.10 For statements
    - §9.4.4.11 Break, continue, and goto statements
    - §9.4.4.12 Throw statements
    - §9.4.4.13 Return statements
    - §9.4.4.14 Try-catch statements
    - §9.4.4.15 Try-finally statements
    - §9.4.4.16 Try-catch-finally statements
    - §9.4.4.17 Foreach statements
    - §9.4.4.18 Using statements
    - §9.4.4.19 Lock statements
    - §9.4.4.20 Yield statements
    - §9.4.4.21 General rules for constant expressions
    - §9.4.4.22 General rules for simple expressions
    - §9.4.4.23 General rules for expressions with embedded expressions
    - §9.4.4.24 Invocation expressions and object creation expressions
    - §9.4.4.25 Simple and deconstructing assignment expressions
    - §9.4.4.26 && expressions
    - §9.4.4.27 || expressions
    - §9.4.4.28 ! expressions
    - §9.4.4.29 ?? expressions
    - §9.4.4.30 ?: expressions
    - §9.4.4.31 Anonymous functions
    - §9.4.4.32 Throw expressions
    - §9.4.4.33 Rules for variables in local functions
    - §9.4.4.34 is-pattern expressions
    - §9.4.4.35 ?. expressions
    - §9.4.4.36 Boolean constant expressions
    - §9.4.4.37 ==/!= expressions
    - §9.4.4.38 is operator and is pattern expressions
- §9.5 Variable references
- §9.6 Atomicity of variable references
- §9.7 Reference variables and returns
  - §9.7.1 General
  - §9.7.2 Ref safe contexts
    - §9.7.2.1 General
    - §9.7.2.2 Local variable ref safe context
    - §9.7.2.3 Parameter ref safe context
    - §9.7.2.4 Field ref safe context
    - §9.7.2.5 Operators
    - §9.7.2.6 Function invocation
    - §9.7.2.7 Values
    - §9.7.2.8 Constructor invocations
    - §9.7.2.9 Limitations on reference variables
  - §9.7.3 The scoped modifier
  - §9.7.4 Parameter scope variance
§10 Conversions
- §10.1 General
- §10.2 Implicit conversions
  - §10.2.1 General
  - §10.2.2 Identity conversion
  - §10.2.3 Implicit numeric conversions
  - §10.2.4 Implicit enumeration conversions
  - §10.2.5 Implicit interpolated string conversions
  - §10.2.6 Implicit nullable conversions
  - §10.2.7 Null literal conversions
  - §10.2.8 Implicit reference conversions
  - §10.2.9 Boxing conversions
  - §10.2.10 Implicit dynamic conversions
  - §10.2.11 Implicit constant expression conversions
  - §10.2.12 Implicit conversions involving type parameters
  - §10.2.13 Implicit tuple conversions
  - §10.2.14 User-defined implicit conversions
  - §10.2.15 Anonymous function conversions and method group conversions
  - §10.2.16 Default literal conversions
  - §10.2.17 Implicit throw conversions
  - §10.2.18 Switch expression conversion
  - §10.2.19 Implicit object-creation conversions
  - §10.2.20 Implicit conditional expression conversions
  - §10.2.21 Anonymous function type conversion
  - §10.2.22 Implicit collection expression conversions
  - §10.2.23 Implicit inline array conversions
- §10.3 Explicit conversions
  - §10.3.1 General
  - §10.3.2 Explicit numeric conversions
  - §10.3.3 Explicit enumeration conversions
  - §10.3.4 Explicit nullable conversions
  - §10.3.5 Explicit reference conversions
  - §10.3.6 Explicit tuple conversions
  - §10.3.7 Unboxing conversions
  - §10.3.8 Explicit conversions involving type parameters
  - §10.3.9 User-defined explicit conversions
- §10.4 Standard conversions
  - §10.4.1 General
  - §10.4.2 Standard implicit conversions
  - §10.4.3 Standard explicit conversions
- §10.5 User-defined conversions
  - §10.5.1 General
  - §10.5.2 Permitted user-defined conversions
  - §10.5.3 Evaluation of user-defined conversions
  - §10.5.4 User-defined implicit conversions
  - §10.5.5 User-defined explicit conversions
- §10.6 Conversions involving nullable types
  - §10.6.1 Nullable Conversions
  - §10.6.2 Lifted conversions
- §10.7 Anonymous function conversions
  - §10.7.1 General
  - §10.7.2 Evaluation of anonymous function conversions to delegate types
  - §10.7.3 Evaluation of lambda expression conversions to expression tree types
- §10.8 Method group conversions
§11 Patterns and pattern matching
- §11.1 General
- §11.2 Pattern forms
  - §11.2.1 General
  - §11.2.2 Declaration pattern
  - §11.2.3 Constant pattern
  - §11.2.4 Var pattern
  - §11.2.5 Positional pattern
  - §11.2.6 Property pattern
  - §11.2.7 Discard pattern
  - §11.2.8 Type pattern
  - §11.2.9 Relational pattern
  - §11.2.10 Logical pattern
  - §11.2.11 List pattern
  - §11.2.12 Slice pattern
§12 Expressions
- §12.1 General
- §12.2 Expression classifications
  - §12.2.1 General
  - §12.2.2 Values of expressions
- §12.3 Static and Dynamic Binding
  - §12.3.1 General
  - §12.3.2 Binding-time
  - §12.3.3 Dynamic binding
  - §12.3.4 Types of subexpressions
- §12.4 Operators
  - §12.4.1 General
  - §12.4.2 Operator precedence and associativity
  - §12.4.3 Operator overloading
  - §12.4.4 Unary operator overload resolution
  - §12.4.5 Binary operator overload resolution
  - §12.4.6 Candidate user-defined operators
  - §12.4.7 Numeric promotions
    - §12.4.7.1 General
    - §12.4.7.2 Unary numeric promotions
    - §12.4.7.3 Binary numeric promotions
  - §12.4.8 Lifted operators
- §12.5 Member lookup
  - §12.5.1 General
  - §12.5.2 Base types
- §12.6 Function members
  - §12.6.1 General
  - §12.6.2 Argument lists
    - §12.6.2.1 General
    - §12.6.2.2 Corresponding parameters
    - §12.6.2.3 Run-time evaluation of argument lists
  - §12.6.3 Type inference
    - §12.6.3.1 General
    - §12.6.3.2 The first phase
    - §12.6.3.3 The second phase
    - §12.6.3.4 Input types
    - §12.6.3.5 Output types
    - §12.6.3.6 Dependence
    - §12.6.3.7 Input type inferences
    - §12.6.3.8 Output type inferences
    - §12.6.3.9 Explicit parameter type inferences
    - §12.6.3.10 Exact inferences
    - §12.6.3.11 Lower-bound inferences
    - §12.6.3.12 Upper-bound inferences
    - §12.6.3.13 Fixing
    - §12.6.3.14 Inferred return type
    - §12.6.3.15 Explicit return type inference
    - §12.6.3.16 Type inference for conversion of method groups
    - §12.6.3.17 Finding the best common type of a set of expressions
  - §12.6.4 Overload resolution
    - §12.6.4.1 General
    - §12.6.4.2 Applicable function member
    - §12.6.4.3 Better function member
    - §12.6.4.4 Better parameter-passing mode
    - §12.6.4.5 Better conversion from expression
    - §12.6.4.6 Exactly matching expression
    - §12.6.4.7 Better conversion target
    - §12.6.4.8 Overloading in generic classes
  - §12.6.5 Compile-time checking of dynamic member invocation
  - §12.6.6 Function member invocation
    - §12.6.6.1 General
    - §12.6.6.2 Invocations on boxed instances
- §12.7 Deconstruction
- §12.8 Primary expressions
  - §12.8.1 General
  - §12.8.2 Literals
  - §12.8.3 Interpolated string expressions
  - §12.8.4 Simple names
  - §12.8.5 Parenthesized expressions
  - §12.8.6 Tuple literals
  - §12.8.7 Member access
    - §12.8.7.1 General
    - §12.8.7.2 Identical simple names and type names
  - §12.8.8 Null Conditional Member Access
  - §12.8.9 Null-forgiving expressions
    - §12.8.9.1 General
    - §12.8.9.2 Overriding a “maybe null” determination
    - §12.8.9.3 Overriding other null analysis warnings
  - §12.8.10 Invocation expressions
    - §12.8.10.1 General
    - §12.8.10.2 Method invocations
    - §12.8.10.3 Extension method invocations
    - §12.8.10.4 Delegate invocations
  - §12.8.11 Null Conditional Invocation Expression
  - §12.8.12 Element access
    - §12.8.12.1 General
    - §12.8.12.2 Array access
    - §12.8.12.3 Inline array element access
    - §12.8.12.4 String access
    - §12.8.12.5 Indexer access
  - §12.8.13 Null Conditional Element Access
  - §12.8.14 This access
  - §12.8.15 Base access
  - §12.8.16 Postfix increment and decrement operators
  - §12.8.17 The new operator
    - §12.8.17.1 General
    - §12.8.17.2 Object creation expressions
      - §12.8.17.2.1 General
      - §12.8.17.2.2 Object initializers
      - §12.8.17.2.3 Collection initializers
    - §12.8.17.3 Anonymous object creation expressions
    - §12.8.17.4 Array creation expressions
    - §12.8.17.5 Delegate creation expressions
  - §12.8.18 The typeof operator
  - §12.8.19 The sizeof operator
  - §12.8.20 The checked and unchecked operators
  - §12.8.21 Default value expressions
  - §12.8.22 Stack allocation
  - §12.8.23 The nameof operator
  - §12.8.24 Anonymous method expressions
  - §12.8.25 Collection expressions
- §12.9 Unary operators
  - §12.9.1 General
  - §12.9.2 Unary plus operator
  - §12.9.3 Unary minus operator
  - §12.9.4 Logical negation operator
  - §12.9.5 Bitwise complement operator
  - §12.9.6 Index from-end operator
  - §12.9.7 Prefix increment and decrement operators
  - §12.9.8 Cast expressions
  - §12.9.9 Await expressions
    - §12.9.9.1 General
    - §12.9.9.2 Awaitable expressions
    - §12.9.9.3 Classification of await expressions
    - §12.9.9.4 Run-time evaluation of await expressions
- §12.10 With expressions
- §12.11 Range operator
- §12.12 Switch expression
- §12.13 Arithmetic operators
  - §12.13.1 General
  - §12.13.2 Multiplication operator
  - §12.13.3 Division operator
  - §12.13.4 Remainder operator
  - §12.13.5 Addition operator
  - §12.13.6 Subtraction operator
- §12.14 Shift operators
- §12.15 Relational and type-testing operators
  - §12.15.1 General
  - §12.15.2 Integer comparison operators
  - §12.15.3 Floating-point comparison operators
  - §12.15.4 Decimal comparison operators
  - §12.15.5 Boolean equality operators
  - §12.15.6 Enumeration comparison operators
  - §12.15.7 Reference type equality operators
  - §12.15.8 String equality operators
  - §12.15.9 Delegate equality operators
  - §12.15.10 Equality operators between nullable value types and the null literal
  - §12.15.11 Tuple equality operators
  - §12.15.12 The is operator
    - §12.15.12.1 The is-type operator
    - §12.15.12.2 The is-pattern operator
  - §12.15.13 The as operator
- §12.16 Logical operators
  - §12.16.1 General
  - §12.16.2 Integer logical operators
  - §12.16.3 Enumeration logical operators
  - §12.16.4 Boolean logical operators
  - §12.16.5 Nullable Boolean & and | operators
- §12.17 Conditional logical operators
  - §12.17.1 General
  - §12.17.2 Boolean conditional logical operators
  - §12.17.3 User-defined conditional logical operators
- §12.18 The null coalescing operator
- §12.19 The throw expression operator
- §12.20 Declaration expressions
- §12.21 Conditional operator
- §12.22 Anonymous function expressions
  - §12.22.1 General
  - §12.22.2 Anonymous function signatures
  - §12.22.3 Anonymous function bodies
  - §12.22.4 Overload resolution
  - §12.22.5 Anonymous functions and dynamic binding
  - §12.22.6 Outer variables
    - §12.22.6.1 General
    - §12.22.6.2 Captured outer variables
    - §12.22.6.3 Instantiation of local variables
  - §12.22.7 Evaluation of anonymous function expressions
  - §12.22.8 Anonymous function type
  - §12.22.9 Implementation Example
- §12.23 Query expressions
  - §12.23.1 General
  - §12.23.2 Ambiguities in query expressions
  - §12.23.3 Query expression translation
    - §12.23.3.1 General
    - §12.23.3.2 Query expressions with continuations
    - §12.23.3.3 Explicit range variable types
    - §12.23.3.4 Degenerate query expressions
    - §12.23.3.5 From, let, where, join and orderby clauses
    - §12.23.3.6 Select clauses
    - §12.23.3.7 Group clauses
    - §12.23.3.8 Transparent identifiers
  - §12.23.4 The query-expression pattern
- §12.24 Assignment operators
  - §12.24.1 General
  - §12.24.2 Simple assignment
  - §12.24.3 Deconstructing assignment
    - §12.24.3.1 General
    - §12.24.3.2 Abridged deconstructors
  - §12.24.4 Ref assignment
  - §12.24.5 Compound assignment
  - §12.24.6 Event assignment
- §12.25 Expression
- §12.26 Constant expressions
- §12.27 Boolean expressions
§13 Statements
- §13.1 General
- §13.2 End points and reachability
- §13.3 Blocks
  - §13.3.1 General
  - §13.3.2 Statement lists
- §13.4 The empty statement
- §13.5 Labeled statements
- §13.6 Declaration statements
  - §13.6.1 General
  - §13.6.2 Local variable declarations
    - §13.6.2.1 General
    - §13.6.2.2 Implicitly typed local variable declarations
    - §13.6.2.3 Explicitly typed local variable declarations
    - §13.6.2.4 Explicitly typed ref local variable declarations
  - §13.6.3 Local constant declarations
  - §13.6.4 Local function declarations
- §13.7 Expression statements
- §13.8 Selection statements
  - §13.8.1 General
  - §13.8.2 The if statement
  - §13.8.3 The switch statement
- §13.9 Iteration statements
  - §13.9.1 General
  - §13.9.2 The while statement
  - §13.9.3 The do statement
  - §13.9.4 The for statement
  - §13.9.5 The foreach statement
    - §13.9.5.1 General
    - §13.9.5.2 Synchronous foreach
    - §13.9.5.3 Asynchronous foreach
    - §13.9.5.4 Deconstructing foreach
- §13.10 Jump statements
  - §13.10.1 General
  - §13.10.2 The break statement
  - §13.10.3 The continue statement
  - §13.10.4 The goto statement
  - §13.10.5 The return statement
  - §13.10.6 The throw statement
- §13.11 The try statement
- §13.12 The checked and unchecked statements
- §13.13 The lock statement
- §13.14 The using statement
  - §13.14.1 General
  - §13.14.2 Using declaration
- §13.15 The yield statement
§14 Namespaces
- §14.1 General
- §14.2 Compilation units
- §14.3 Namespace declarations
- §14.4 Extern alias directives
- §14.5 Global using directives
  - §14.5.1 General
  - §14.5.2 Global using alias directives
  - §14.5.3 Global using namespace directives
  - §14.5.4 Global using static directives
- §14.6 Using directives
  - §14.6.1 General
  - §14.6.2 Using alias directives
  - §14.6.3 Using namespace directives
  - §14.6.4 Using static directives
- §14.7 Namespace member declarations
- §14.8 Type declarations
- §14.9 Qualified alias member
  - §14.9.1 General
  - §14.9.2 Uniqueness of aliases
§15 Classes
- §15.1 General
- §15.2 Class declarations
  - §15.2.1 General
  - §15.2.2 Class modifiers
    - §15.2.2.1 General
    - §15.2.2.2 Abstract classes
    - §15.2.2.3 Sealed classes
    - §15.2.2.4 Static classes
      - §15.2.2.4.1 General
      - §15.2.2.4.2 Referencing static class types
  - §15.2.3 Type parameters
  - §15.2.4 Class base specification
    - §15.2.4.1 General
    - §15.2.4.2 Base classes
    - §15.2.4.3 Interface implementations
  - §15.2.5 Type parameter constraints
  - §15.2.6 Class body
  - §15.2.7 Partial type declarations
- §15.3 Class members
  - §15.3.1 General
  - §15.3.2 The instance type
  - §15.3.3 Members of constructed types
  - §15.3.4 Inheritance
  - §15.3.5 The new modifier
  - §15.3.6 Access modifiers
  - §15.3.7 Constituent types
  - §15.3.8 Static and instance members
  - §15.3.9 Nested types
    - §15.3.9.1 General
    - §15.3.9.2 Fully qualified name
    - §15.3.9.3 Declared accessibility
    - §15.3.9.4 Hiding
    - §15.3.9.5 this access
    - §15.3.9.6 Access to private and protected members of the containing type
    - §15.3.9.7 Nested types in generic classes
  - §15.3.10 Reserved member names
    - §15.3.10.1 General
    - §15.3.10.2 Member names reserved for properties
    - §15.3.10.3 Member names reserved for events
    - §15.3.10.4 Member names reserved for indexers
    - §15.3.10.5 Member names reserved for finalizers
    - §15.3.10.6 Method names reserved for operators
- §15.4 Constants
- §15.5 Fields
  - §15.5.1 General
  - §15.5.2 Static and instance fields
  - §15.5.3 Readonly fields
    - §15.5.3.1 General
    - §15.5.3.2 Using static readonly fields for constants
    - §15.5.3.3 Versioning of constants and static readonly fields
  - §15.5.4 Volatile fields
  - §15.5.5 Field initialization
  - §15.5.6 Variable initializers
    - §15.5.6.1 General
    - §15.5.6.2 Static field initialization
    - §15.5.6.3 Instance field initialization
- §15.6 Methods
  - §15.6.1 General
  - §15.6.2 Method parameters
    - §15.6.2.1 General
    - §15.6.2.2 Value parameters
    - §15.6.2.3 By-reference parameters
      - §15.6.2.3.1 General
      - §15.6.2.3.2 Input parameters
      - §15.6.2.3.3 Reference parameters
      - §15.6.2.3.4 Output parameters
    - §15.6.2.4 Parameter collections
  - §15.6.3 Static and instance methods
  - §15.6.4 Virtual methods
  - §15.6.5 Override methods
  - §15.6.6 Sealed methods
  - §15.6.7 Abstract methods
  - §15.6.8 External methods
  - §15.6.9 Partial methods
    - §15.6.9.1 General
    - §15.6.9.2 Optional partial methods
    - §15.6.9.3 Required partial methods
  - §15.6.10 Extension methods
  - §15.6.11 Method body
- §15.7 Properties
  - §15.7.1 General
  - §15.7.2 Static and instance properties
  - §15.7.3 Accessors
    - §15.7.3.1 General
    - §15.7.3.2 Set and get accessors
    - §15.7.3.3 Init accessors
  - §15.7.4 Automatically implemented properties
  - §15.7.5 Accessibility
  - §15.7.6 Virtual, sealed, override, and abstract accessors
  - §15.7.7 Partial properties
- §15.8 Events
  - §15.8.1 General
  - §15.8.2 Field-like events
  - §15.8.3 Event accessors
  - §15.8.4 Static and instance events
  - §15.8.5 Virtual, sealed, override, and abstract accessors
- §15.9 Indexers
  - §15.9.1 General
  - §15.9.2 Indexer and Property Differences
  - §15.9.3 Partial indexers
- §15.10 Operators
  - §15.10.1 General
  - §15.10.2 Unary operators
  - §15.10.3 Binary operators
  - §15.10.4 Conversion operators
- §15.11 Instance constructors
  - §15.11.1 General
  - §15.11.2 Constructor initializers
  - §15.11.3 Instance variable initializers
  - §15.11.4 Constructor execution
  - §15.11.5 Default constructors
  - §15.11.6 Primary constructors
- §15.12 Static constructors
- §15.13 Finalizers
- §15.14 Async Functions
  - §15.14.1 General
  - §15.14.2 Task-type builder pattern
  - §15.14.3 Evaluation of a task-returning async function
  - §15.14.4 Evaluation of a void-returning async function
- §15.15 Synchronous and asynchronous iterators
  - §15.15.1 General
  - §15.15.2 Enumerator interfaces
  - §15.15.3 Enumerable interfaces
  - §15.15.4 Yield type
  - §15.15.5 Enumerator objects
    - §15.15.5.1 General
    - §15.15.5.2 Advance the enumerator
    - §15.15.5.3 Retrieve the current value
    - §15.15.5.4 Dispose of resources
  - §15.15.6 Enumerable objects
    - §15.15.6.1 General
    - §15.15.6.2 The GetEnumerator or GetAsyncEnumerator method
- §15.16 Record classes
  - §15.16.1 General
  - §15.16.2 Class members
  - §15.16.3 Instance constructors
  - §15.16.4 Implicit record class members
    - §15.16.4.1 General
    - §15.16.4.2 Copy constructors
    - §15.16.4.3 Equality members
    - §15.16.4.4 Copy and clone members
    - §15.16.4.5 Printing members
    - §15.16.4.6 Positional record class members
      - §15.16.4.6.1 General
      - §15.16.4.6.2 Primary constructor
      - §15.16.4.6.3 Properties
      - §15.16.4.6.4 Deconstruct
- §15.17 Declaring a collection type
  - §15.17.1 General
  - §15.17.2 Collection construction
- §15.18 Record class and non-record class differences
§16 Structs
- §16.1 General
- §16.2 Struct declarations
  - §16.2.1 General
  - §16.2.2 Struct modifiers
  - §16.2.3 Ref modifier
  - §16.2.4 Partial modifier
  - §16.2.5 Struct interfaces
  - §16.2.6 Struct body
- §16.3 Struct members
  - §16.3.1 General
  - §16.3.2 Readonly members
- §16.4 Primary constructors
- §16.5 Record structs
  - §16.5.1 General
  - §16.5.2 Struct members
  - §16.5.3 Implicit record struct members
    - §16.5.3.1 General
    - §16.5.3.2 Primary constructors
    - §16.5.3.3 Equality members
    - §16.5.3.4 Printing members
    - §16.5.3.5 Positional record struct members
      - §16.5.3.5.1 General
      - §16.5.3.5.2 Primary constructor
      - §16.5.3.5.3 Properties
      - §16.5.3.5.4 Deconstruct
- §16.6 Inline arrays
- §16.7 Record struct and non-record struct differences
- §16.8 Class and struct differences
  - §16.8.1 General
  - §16.8.2 Value semantics
  - §16.8.3 Inheritance
  - §16.8.4 Assignment
  - §16.8.5 Default values
  - §16.8.6 Boxing and unboxing
  - §16.8.7 Meaning of this
  - §16.8.8 Fields
    - §16.8.8.1 Field initializers
    - §16.8.8.2 Ref fields
  - §16.8.9 Constructors
  - §16.8.10 Static constructors
  - §16.8.11 Properties
  - §16.8.12 Methods
  - §16.8.13 Indexers
  - §16.8.14 Events
  - §16.8.15 Safe context constraint
    - §16.8.15.1 General
    - §16.8.15.2 Parameter safe context
    - §16.8.15.3 Local variable safe context
    - §16.8.15.4 Field safe context
    - §16.8.15.5 Operators
    - §16.8.15.6 Method and property invocation
    - §16.8.15.7 Method arguments must match
    - §16.8.15.8 Infer safe-context of declaration expressions
    - §16.8.15.9 Object initializer safe context
    - §16.8.15.10 stackalloc
    - §16.8.15.11 Constructor invocations
§17 Arrays
- §17.1 General
- §17.2 Array types
  - §17.2.1 General
  - §17.2.2 The System.Array type
  - §17.2.3 Arrays and the generic collection interfaces
- §17.3 Array creation
- §17.4 Array element access
- §17.5 Array members
- §17.6 Array covariance
- §17.7 Array initializers
§18 Extended indexing and slicing
- §18.1 General
- §18.2 The Index type
- §18.3 The Range type
- §18.4 Pattern-based implicit support for Index and Range
  - §18.4.1 General
  - §18.4.2 Implicit Index support
  - §18.4.3 Implicit Range support
§19 Interfaces
- §19.1 General
- §19.2 Interface declarations
  - §19.2.1 General
  - §19.2.2 Interface modifiers
  - §19.2.3 Variant type parameter lists
    - §19.2.3.1 General
    - §19.2.3.2 Variance safety
    - §19.2.3.3 Variance conversion
  - §19.2.4 Base interfaces
- §19.3 Interface body
- §19.4 Interface members
  - §19.4.1 General
  - §19.4.2 Interface fields
  - §19.4.3 Interface methods
  - §19.4.4 Interface properties
  - §19.4.5 Interface events
  - §19.4.6 Interface indexers
  - §19.4.7 Interface operators
  - §19.4.8 Interface static constructors
  - §19.4.9 Interface nested types
  - §19.4.10 Most specific implementation
  - §19.4.11 Interface member access
- §19.5 Qualified interface member names
- §19.6 Interface implementations
  - §19.6.1 General
  - §19.6.2 Explicit interface member implementations
  - §19.6.3 Uniqueness of implemented interfaces
  - §19.6.4 Implementation of generic methods
  - §19.6.5 Interface mapping
  - §19.6.6 Interface implementation inheritance
  - §19.6.7 Interface re-implementation
  - §19.6.8 Abstract classes and interfaces
§20 Enums
- §20.1 General
- §20.2 Enum declarations
- §20.3 Enum modifiers
- §20.4 Enum members
- §20.5 The System.Enum type
- §20.6 Enum values and operations
§21 Delegates
- §21.1 General
- §21.2 Delegate declarations
- §21.3 Delegate members
- §21.4 Delegate compatibility
- §21.5 Delegate instantiation
- §21.6 Delegate invocation
§22 Exceptions
- §22.1 General
- §22.2 Causes of exceptions
- §22.3 The System.Exception class
- §22.4 How exceptions are handled
- §22.5 Common exception classes
§23 Attributes
- §23.1 General
- §23.2 Attribute classes
  - §23.2.1 General
  - §23.2.2 Attribute usage
  - §23.2.3 Positional and named parameters
  - §23.2.4 Attribute parameter types
- §23.3 Attribute specification
- §23.4 Attribute instances
  - §23.4.1 General
  - §23.4.2 Compilation of an attribute
  - §23.4.3 Run-time retrieval of an attribute instance
- §23.5 Reserved attributes
  - §23.5.1 General
  - §23.5.2 The AttributeUsage attribute
  - §23.5.3 The Conditional attribute
    - §23.5.3.1 General
    - §23.5.3.2 Conditional methods
    - §23.5.3.3 Conditional local functions
    - §23.5.3.4 Conditional attribute classes
  - §23.5.4 The Obsolete attribute
  - §23.5.5 The AsyncMethodBuilder attribute
  - §23.5.6 Caller-info attributes
    - §23.5.6.1 General
    - §23.5.6.2 The CallerLineNumber attribute
    - §23.5.6.3 The CallerFilePath attribute
    - §23.5.6.4 The CallerMemberName attribute
    - §23.5.6.5 The CallerArgumentExpression attribute
  - §23.5.7 Code analysis attributes
    - §23.5.7.1 General
    - §23.5.7.2 The AllowNull attribute
    - §23.5.7.3 The DisallowNull attribute
    - §23.5.7.4 The DoesNotReturn attribute
    - §23.5.7.5 The DoesNotReturnIf attribute
    - §23.5.7.6 The MaybeNull attribute
    - §23.5.7.7 The MaybeNullWhen attribute
    - §23.5.7.8 The MemberNotNull attribute
    - §23.5.7.9 The MemberNotNullWhen attribute
    - §23.5.7.10 The NotNull attribute
    - §23.5.7.11 The NotNullIfNotNull attribute
    - §23.5.7.12 The NotNullWhen attribute
  - §23.5.8 The UnscopedRef attribute
  - §23.5.9 The ScopedRef attribute
  - §23.5.10 The EnumeratorCancellation attribute
  - §23.5.11 The ModuleInitializer attribute
    - §23.5.11.1 Custom interpolated string expression handlers
      - §23.5.11.1.1 Declaring a custom handler
      - §23.5.11.1.2 Inhibiting a custom handler
      - §23.5.11.1.3 Passing information to/from a custom handler
  - §23.5.12 Required member attributes
    - §23.5.12.1 The SetsRequiredMembers attribute
    - §23.5.12.2 The RequiredMember attribute
  - §23.5.13 The CollectionBuilder attribute
  - §23.5.14 The InlineArray attribute
  - §23.5.15 The OverloadResolutionPriority attribute
- §23.6 Attributes for interoperation
§24 Unsafe code
- §24.1 General
- §24.2 Unsafe contexts
- §24.3 Pointer types
  - §24.3.1 General
  - §24.3.2 Data pointers
  - §24.3.3 Function pointers
  - §24.3.4 Void pointers
- §24.4 Fixed and moveable variables
- §24.5 Pointer conversions
  - §24.5.1 General
  - §24.5.2 Pointer arrays
- §24.6 Pointers in expressions
  - §24.6.1 General
  - §24.6.2 Pointer indirection
  - §24.6.3 Pointer member access
  - §24.6.4 Pointer element access
  - §24.6.5 The address-of operator
  - §24.6.6 Pointer increment and decrement
  - §24.6.7 Pointer arithmetic
  - §24.6.8 Pointer comparison
  - §24.6.9 The sizeof operator
- §24.7 The fixed statement
- §24.8 Fixed-size buffers
  - §24.8.1 General
  - §24.8.2 Fixed-size buffer declarations
  - §24.8.3 Fixed-size buffers in expressions
  - §24.8.4 Definite assignment checking
- §24.9 Stack allocation
§A Grammar
- §A.1 General
- §A.2 Lexical grammar
- §A.3 Syntactic grammar
- §A.4 Grammar extensions for unsafe code
§B Portability issues
- §B.1 General
- §B.2 Undefined behavior
- §B.3 Implementation-defined behavior
- §B.4 Unspecified behavior
- §B.5 Other issues
§C Standard library
- §C.1 General
- §C.2 Standard Library Types defined in ISO/IEC 23271
- §C.3 Standard Library Types not defined in ISO/IEC 23271
- §C.4 Format Specifications
- §C.5 Library Type Abbreviations
§D Documentation comments
- §D.1 General
- §D.2 Introduction
- §D.3 Recommended tags
  - §D.3.1 General
  - §D.3.2 <c>
  - §D.3.3 <code>
  - §D.3.4 <example>
  - §D.3.5 <exception>
  - §D.3.6 <include>
  - §D.3.7 <list>
  - §D.3.8 <para>
  - §D.3.9 <param>
  - §D.3.10 <paramref>
  - §D.3.11 <permission>
  - §D.3.12 <remarks>
  - §D.3.13 <returns>
  - §D.3.14 <see>
  - §D.3.15 <seealso>
  - §D.3.16 <summary>
  - §D.3.17 <typeparam>
  - §D.3.18 <typeparamref>
  - §D.3.19 <value>
- §D.4 Processing the documentation file
  - §D.4.1 General
  - §D.4.2 ID string format
  - §D.4.3 ID string examples
- §D.5 An example
  - §D.5.1 C# source code
  - §D.5.2 Resulting XML
§E Bibliography

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Last updated on 2026-09-22

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