Detailed table of contents
July 2, 2026 · View on GitHub
- Foreword
- Introduction
- §1 Scope
- §2 Normative references
- §3 Terms and definitions
- §4 General description
- §5 Conformance
- §6 Lexical structure
- §7 Basic concepts
- §8 Types
- §8.1 General
- §8.2 Reference 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
- §8.3.12 Nullable value types
- §8.3.13 Boxing and unboxing
- §8.4 Constructed types
- §8.5 Type parameters
- §8.6 Expression tree types
- §8.7 The dynamic type
- §8.8 Unmanaged types
- §8.9 Reference Types and nullability
- §9 Variables
- §9.1 General
- §9.2 Variable categories
- §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
- §9.5 Variable references
- §9.6 Atomicity of variable references
- §9.7 Reference variables and returns
- §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
- §10.3 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
- §10.5 User-defined conversions
- §10.6 Conversions involving nullable types
- §10.7 Anonymous function conversions
- §10.8 Method group conversions
- §11 Patterns and pattern matching
- §12 Expressions
- §12.1 General
- §12.2 Expression classifications
- §12.3 Static and Dynamic Binding
- §12.4 Operators
- §12.5 Member lookup
- §12.6 Function members
- §12.6.1 General
- §12.6.2 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 Type inference for conversion of method groups
- §12.6.3.16 Finding the best common type of a set of expressions
- §12.6.4 Overload resolution
- §12.6.5 Compile-time checking of dynamic member invocation
- §12.6.6 Function member invocation
- §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
- §12.8.8 Null Conditional Member Access
- §12.8.9 Null-forgiving expressions
- §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 String access
- §12.8.12.4 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
- §12.9 Unary operators
- §12.10 Range operator
- §12.11 Switch expression
- §12.12 Arithmetic operators
- §12.13 Shift operators
- §12.14 Relational and type-testing operators
- §12.14.1 General
- §12.14.2 Integer comparison operators
- §12.14.3 Floating-point comparison operators
- §12.14.4 Decimal comparison operators
- §12.14.5 Boolean equality operators
- §12.14.6 Enumeration comparison operators
- §12.14.7 Reference type equality operators
- §12.14.8 String equality operators
- §12.14.9 Delegate equality operators
- §12.14.10 Equality operators between nullable value types and the null literal
- §12.14.11 Tuple equality operators
- §12.14.12 The is operator
- §12.14.12.1 The is-type operator
- §12.14.12.2 The is-pattern operator
- §12.14.13 The as operator
- §12.15 Logical operators
- §12.16 Conditional logical operators
- §12.17 The null coalescing operator
- §12.18 The throw expression operator
- §12.19 Declaration expressions
- §12.20 Conditional operator
- §12.21 Anonymous function expressions
- §12.21.1 General
- §12.21.2 Anonymous function signatures
- §12.21.3 Anonymous function bodies
- §12.21.4 Overload resolution
- §12.21.5 Anonymous functions and dynamic binding
- §12.21.6 Outer variables
- §12.21.6.1 General
- §12.21.6.2 Captured outer variables
- §12.21.6.3 Instantiation of local variables
- §12.21.7 Evaluation of anonymous function expressions
- §12.21.8 Implementation Example
- §12.22 Query expressions
- §12.22.1 General
- §12.22.2 Ambiguities in query expressions
- §12.22.3 Query expression translation
- §12.22.3.1 General
- §12.22.3.2 Query expressions with continuations
- §12.22.3.3 Explicit range variable types
- §12.22.3.4 Degenerate query expressions
- §12.22.3.5 From, let, where, join and orderby clauses
- §12.22.3.6 Select clauses
- §12.22.3.7 Group clauses
- §12.22.3.8 Transparent identifiers
- §12.22.4 The query-expression pattern
- §12.23 Assignment operators
- §12.23.1 General
- §12.23.2 Simple assignment
- §12.23.3 Deconstructing assignment
- §12.23.3.1 General
- §12.23.3.2 Abridged deconstructors
- §12.23.4 Ref assignment
- §12.23.5 Compound assignment
- §12.23.6 Event assignment
- §12.24 Expression
- §12.25 Constant expressions
- §12.26 Boolean expressions
- §13 Statements
- §13.1 General
- §13.2 End points and reachability
- §13.3 Blocks
- §13.4 The empty statement
- §13.5 Labeled statements
- §13.6 Declaration statements
- §13.7 Expression statements
- §13.8 Selection statements
- §13.9 Iteration statements
- §13.10 Jump statements
- §13.11 The try statement
- §13.12 The checked and unchecked statements
- §13.13 The lock statement
- §13.14 The using statement
- §13.15 The yield statement
- §14 Namespaces
- §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
- §15.2.5 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
- §15.3.10 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
- §15.6 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 arrays
- §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
- §15.6.10 Extension methods
- §15.6.11 Method body
- §15.7 Properties
- §15.8 Events
- §15.9 Indexers
- §15.10 Operators
- §15.11 Instance constructors
- §15.12 Static constructors
- §15.13 Finalizers
- §15.14 Async Functions
- §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
- §16 Structs
- §16.1 General
- §16.2 Struct declarations
- §16.3 Struct members
- §16.4 Class and struct differences
- §16.4.1 General
- §16.4.2 Value semantics
- §16.4.3 Inheritance
- §16.4.4 Assignment
- §16.4.5 Default values
- §16.4.6 Boxing and unboxing
- §16.4.7 Meaning of this
- §16.4.8 Field initializers
- §16.4.9 Constructors
- §16.4.10 Static constructors
- §16.4.11 Properties
- §16.4.12 Methods
- §16.4.13 Indexers
- §16.4.14 Events
- §16.4.15 Safe context constraint
- §16.4.15.1 General
- §16.4.15.2 Parameter safe context
- §16.4.15.3 Local variable safe context
- §16.4.15.4 Field safe context
- §16.4.15.5 Operators
- §16.4.15.6 Method and property invocation
- §16.4.15.7 stackalloc
- §16.4.15.8 Constructor invocations
- §17 Arrays
- §18 Extended indexing and slicing
- §19 Interfaces
- §19.1 General
- §19.2 Interface declarations
- §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
- §20 Enums
- §21 Delegates
- §22 Exceptions
- §23 Attributes
- §23.1 General
- §23.2 Attribute classes
- §23.3 Attribute specification
- §23.4 Attribute instances
- §23.5 Reserved attributes
- §23.5.1 General
- §23.5.2 The AttributeUsage attribute
- §23.5.3 The Conditional attribute
- §23.5.4 The Obsolete attribute
- §23.5.5 The AsyncMethodBuilder attribute
- §23.5.6 Caller-info attributes
- §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 NotNull attribute
- §23.5.7.9 The NotNullIfNotNull attribute
- §23.5.7.10 The NotNullWhen attribute
- §23.5.8 The EnumeratorCancellation attribute
- §23.6 Attributes for interoperation
- §24 Unsafe code
- §A Grammar
- §B Portability issues
- §C Standard library
- §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.5 An example
- §E Bibliography