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All C# errors and warnings. NOTE: this list is out of date. See https://github.com/thomaslevesque/GenerateCSharpErrors/blob/master/CSharpErrorsAndWarnings.md for a more recent version

All C# errors and warnings

Parsed from the Roslyn source code using Roslyn.

Code Severity Message
CS0006 Error Metadata file '{0}' could not be found
CS0009 Fatal Metadata file '{0}' could not be opened -- {1}
CS0012 Error The type '{0}' is defined in an assembly that is not referenced. You must add a reference to assembly '{1}'.
CS0016 Error Could not write to output file '{0}' -- '{1}'
CS0017 Error Program has more than one entry point defined. Compile with /main to specify the type that contains the entry point.
CS0019 Error Operator '{0}' cannot be applied to operands of type '{1}' and '{2}'
CS0020 Error Division by constant zero
CS0021 Error Cannot apply indexing with [] to an expression of type '{0}'
CS0022 Error Wrong number of indices inside []; expected {0}
CS0023 Error Operator '{0}' cannot be applied to operand of type '{1}'
CS0026 Error Keyword 'this' is not valid in a static property, static method, or static field initializer
CS0027 Error Keyword 'this' is not available in the current context
CS0028 Warning '{0}' has the wrong signature to be an entry point
CS0029 Error Cannot implicitly convert type '{0}' to '{1}'
CS0030 Error Cannot convert type '{0}' to '{1}'
CS0031 Error Constant value '{0}' cannot be converted to a '{1}'
CS0034 Error Operator '{0}' is ambiguous on operands of type '{1}' and '{2}'
CS0035 Error Operator '{0}' is ambiguous on an operand of type '{1}'
CS0036 Error An out parameter cannot have the In attribute
CS0037 Error Cannot convert null to '{0}' because it is a non-nullable value type
CS0039 Error Cannot convert type '{0}' to '{1}' via a reference conversion, boxing conversion, unboxing conversion, wrapping conversion, or null type conversion
CS0041 Fatal Unexpected error writing debug information -- '{0}'
CS0050 Error Inconsistent accessibility: return type '{1}' is less accessible than method '{0}'
CS0051 Error Inconsistent accessibility: parameter type '{1}' is less accessible than method '{0}'
CS0052 Error Inconsistent accessibility: field type '{1}' is less accessible than field '{0}'
CS0053 Error Inconsistent accessibility: property type '{1}' is less accessible than property '{0}'
CS0054 Error Inconsistent accessibility: indexer return type '{1}' is less accessible than indexer '{0}'
CS0055 Error Inconsistent accessibility: parameter type '{1}' is less accessible than indexer '{0}'
CS0056 Error Inconsistent accessibility: return type '{1}' is less accessible than operator '{0}'
CS0057 Error Inconsistent accessibility: parameter type '{1}' is less accessible than operator '{0}'
CS0058 Error Inconsistent accessibility: return type '{1}' is less accessible than delegate '{0}'
CS0059 Error Inconsistent accessibility: parameter type '{1}' is less accessible than delegate '{0}'
CS0060 Error Inconsistent accessibility: base class '{1}' is less accessible than class '{0}'
CS0061 Error Inconsistent accessibility: base interface '{1}' is less accessible than interface '{0}'
CS0065 Error '{0}': event property must have both add and remove accessors
CS0066 Error '{0}': event must be of a delegate type
CS0067 Warning The event '{0}' is never used
CS0068 Error '{0}': instance event in interface cannot have initializer
CS0070 Error The event '{0}' can only appear on the left hand side of += or -= (except when used from within the type '{1}')
CS0071 Error An explicit interface implementation of an event must use event accessor syntax
CS0072 Error '{0}': cannot override; '{1}' is not an event
CS0073 Error An add or remove accessor must have a body
CS0074 Error '{0}': abstract event cannot have initializer
CS0075 Error To cast a negative value, you must enclose the value in parentheses.
CS0076 Error The enumerator name '{0}' is reserved and cannot be used
CS0077 Error The as operator must be used with a reference type or nullable type ('{0}' is a non-nullable value type)
CS0078 Warning The 'l' suffix is easily confused with the digit '1' -- use 'L' for clarity
CS0079 Error The event '{0}' can only appear on the left hand side of += or -=
CS0080 Error Constraints are not allowed on non-generic declarations
CS0081 Error Type parameter declaration must be an identifier not a type
CS0082 Error Type '{1}' already reserves a member called '{0}' with the same parameter types
CS0100 Error The parameter name '{0}' is a duplicate
CS0101 Error The namespace '{1}' already contains a definition for '{0}'
CS0102 Error The type '{0}' already contains a definition for '{1}'
CS0103 Error The name '{0}' does not exist in the current context
CS0104 Error '{0}' is an ambiguous reference between '{1}' and '{2}'
CS0105 Warning The using directive for '{0}' appeared previously in this namespace
CS0106 Error The modifier '{0}' is not valid for this item
CS0107 Error More than one protection modifier
CS0108 Warning '{0}' hides inherited member '{1}'. Use the new keyword if hiding was intended.
CS0109 Warning The member '{0}' does not hide an accessible member. The new keyword is not required.
CS0110 Error The evaluation of the constant value for '{0}' involves a circular definition
CS0111 Error Type '{1}' already defines a member called '{0}' with the same parameter types
CS0112 Error A static member '{0}' cannot be marked as override, virtual, or abstract
CS0113 Error A member '{0}' marked as override cannot be marked as new or virtual
CS0114 Warning '{0}' hides inherited member '{1}'. To make the current member override that implementation, add the override keyword. Otherwise add the new keyword.
CS0115 Error '{0}': no suitable method found to override
CS0116 Error A namespace cannot directly contain members such as fields or methods
CS0117 Error '{0}' does not contain a definition for '{1}'
CS0118 Error '{0}' is a {1} but is used like a {2}
CS0119 Error '{0}' is a {1}, which is not valid in the given context
CS0120 Error An object reference is required for the non-static field, method, or property '{0}'
CS0121 Error The call is ambiguous between the following methods or properties: '{0}' and '{1}'
CS0122 Error '{0}' is inaccessible due to its protection level
CS0123 Error No overload for '{0}' matches delegate '{1}'
CS0126 Error An object of a type convertible to '{0}' is required
CS0127 Error Since '{0}' returns void, a return keyword must not be followed by an object expression
CS0128 Error A local variable or function named '{0}' is already defined in this scope
CS0131 Error The left-hand side of an assignment must be a variable, property or indexer
CS0132 Error '{0}': a static constructor must be parameterless
CS0133 Error The expression being assigned to '{0}' must be constant
CS0134 Error '{0}' is of type '{1}'. A const field of a reference type other than string can only be initialized with null.
CS0136 Error A local or parameter named '{0}' cannot be declared in this scope because that name is used in an enclosing local scope to define a local or parameter
CS0138 Error A 'using namespace' directive can only be applied to namespaces; '{0}' is a type not a namespace. Consider a 'using static' directive instead
CS0139 Error No enclosing loop out of which to break or continue
CS0140 Error The label '{0}' is a duplicate
CS0143 Error The type '{0}' has no constructors defined
CS0144 Error Cannot create an instance of the abstract class or interface '{0}'
CS0145 Error A const field requires a value to be provided
CS0146 Error Circular base class dependency involving '{0}' and '{1}'
CS0148 Error The delegate '{0}' does not have a valid constructor
CS0149 Error Method name expected
CS0150 Error A constant value is expected
CS0151 Error A switch expression or case label must be a bool, char, string, integral, enum, or corresponding nullable type in C# 6 and earlier.
CS0152 Error The switch statement contains multiple cases with the label value '{0}'
CS0153 Error A goto case is only valid inside a switch statement
CS0154 Error The property or indexer '{0}' cannot be used in this context because it lacks the get accessor
CS0155 Error The type caught or thrown must be derived from System.Exception
CS0156 Error A throw statement with no arguments is not allowed outside of a catch clause
CS0157 Error Control cannot leave the body of a finally clause
CS0158 Error The label '{0}' shadows another label by the same name in a contained scope
CS0159 Error No such label '{0}' within the scope of the goto statement
CS0160 Error A previous catch clause already catches all exceptions of this or of a super type ('{0}')
CS0161 Error '{0}': not all code paths return a value
CS0162 Warning Unreachable code detected
CS0163 Error Control cannot fall through from one case label ('{0}') to another
CS0164 Warning This label has not been referenced
CS0165 Error Use of unassigned local variable '{0}'
CS0168 Warning The variable '{0}' is declared but never used
CS0169 Warning The field '{0}' is never used
CS0170 Error Use of possibly unassigned field '{0}'
CS0171 Error Field '{0}' must be fully assigned before control is returned to the caller
CS0172 Error Type of conditional expression cannot be determined because '{0}' and '{1}' implicitly convert to one another
CS0173 Error Type of conditional expression cannot be determined because there is no implicit conversion between '{0}' and '{1}'
CS0174 Error A base class is required for a 'base' reference
CS0175 Error Use of keyword 'base' is not valid in this context
CS0176 Error Member '{0}' cannot be accessed with an instance reference; qualify it with a type name instead
CS0177 Error The out parameter '{0}' must be assigned to before control leaves the current method
CS0178 Error Invalid rank specifier: expected ',' or ']'
CS0179 Error '{0}' cannot be extern and declare a body
CS0180 Error '{0}' cannot be both extern and abstract
CS0181 Error Attribute constructor parameter '{0}' has type '{1}', which is not a valid attribute parameter type
CS0182 Error An attribute argument must be a constant expression, typeof expression or array creation expression of an attribute parameter type
CS0183 Warning The given expression is always of the provided ('{0}') type
CS0184 Warning The given expression is never of the provided ('{0}') type
CS0185 Error '{0}' is not a reference type as required by the lock statement
CS0186 Error Use of null is not valid in this context
CS0188 Error The 'this' object cannot be used before all of its fields are assigned to
CS0190 Error The __arglist construct is valid only within a variable argument method
CS0191 Error A readonly field cannot be assigned to (except in a constructor or a variable initializer)
CS0192 Error A readonly field cannot be used as a ref or out value (except in a constructor)
CS0193 Error The * or -> operator must be applied to a pointer
CS0196 Error A pointer must be indexed by only one value
CS0197 Warning Using '{0}' as a ref or out value or taking its address may cause a runtime exception because it is a field of a marshal-by-reference class
CS0198 Error A static readonly field cannot be assigned to (except in a static constructor or a variable initializer)
CS0199 Error A static readonly field cannot be used as a ref or out value (except in a static constructor)
CS0200 Error Property or indexer '{0}' cannot be assigned to -- it is read only
CS0201 Error Only assignment, call, increment, decrement, await, and new object expressions can be used as a statement
CS0202 Error foreach requires that the return type '{0}' of '{1}' must have a suitable public 'MoveNext' method and public 'Current' property
CS0204 Error Only 65534 locals, including those generated by the compiler, are allowed
CS0205 Error Cannot call an abstract base member: '{0}'
CS0206 Error A property or indexer may not be passed as an out or ref parameter
CS0208 Error Cannot take the address of, get the size of, or declare a pointer to a managed type ('{0}')
CS0209 Error The type of a local declared in a fixed statement must be a pointer type
CS0210 Error You must provide an initializer in a fixed or using statement declaration
CS0211 Error Cannot take the address of the given expression
CS0212 Error You can only take the address of an unfixed expression inside of a fixed statement initializer
CS0213 Error You cannot use the fixed statement to take the address of an already fixed expression
CS0214 Error Pointers and fixed size buffers may only be used in an unsafe context
CS0215 Error The return type of operator True or False must be bool
CS0216 Error The operator '{0}' requires a matching operator '{1}' to also be defined
CS0217 Error In order to be applicable as a short circuit operator a user-defined logical operator ('{0}') must have the same return type and parameter types
CS0218 Error In order for '{0}' to be applicable as a short circuit operator, its declaring type '{1}' must define operator true and operator false
CS0219 Warning The variable '{0}' is assigned but its value is never used
CS0220 Error The operation overflows at compile time in checked mode
CS0221 Error Constant value '{0}' cannot be converted to a '{1}' (use 'unchecked' syntax to override)
CS0224 Error A method with vararg cannot be generic, be in a generic type, or have a params parameter
CS0225 Error The params parameter must be a single dimensional array
CS0226 Error An __arglist expression may only appear inside of a call or new expression
CS0227 Error Unsafe code may only appear if compiling with /unsafe
CS0229 Error Ambiguity between '{0}' and '{1}'
CS0230 Error Type and identifier are both required in a foreach statement
CS0231 Error A params parameter must be the last parameter in a formal parameter list
CS0233 Error '{0}' does not have a predefined size, therefore sizeof can only be used in an unsafe context
CS0234 Error The type or namespace name '{0}' does not exist in the namespace '{1}' (are you missing an assembly reference?)
CS0236 Error A field initializer cannot reference the non-static field, method, or property '{0}'
CS0238 Error '{0}' cannot be sealed because it is not an override
CS0239 Error '{0}': cannot override inherited member '{1}' because it is sealed
CS0242 Error The operation in question is undefined on void pointers
CS0243 Error The Conditional attribute is not valid on '{0}' because it is an override method
CS0244 Error Neither 'is' nor 'as' is valid on pointer types
CS0245 Error Destructors and object.Finalize cannot be called directly. Consider calling IDisposable.Dispose if available.
CS0246 Error The type or namespace name '{0}' could not be found (are you missing a using directive or an assembly reference?)
CS0247 Error Cannot use a negative size with stackalloc
CS0248 Error Cannot create an array with a negative size
CS0249 Error Do not override object.Finalize. Instead, provide a destructor.
CS0250 Error Do not directly call your base class Finalize method. It is called automatically from your destructor.
CS0251 Warning Indexing an array with a negative index (array indices always start at zero)
CS0252 Warning Possible unintended reference comparison; to get a value comparison, cast the left hand side to type '{0}'
CS0253 Warning Possible unintended reference comparison; to get a value comparison, cast the right hand side to type '{0}'
CS0254 Error The right hand side of a fixed statement assignment may not be a cast expression
CS0255 Error stackalloc may not be used in a catch or finally block
CS0257 Error An __arglist parameter must be the last parameter in a formal parameter list
CS0260 Error Missing partial modifier on declaration of type '{0}'; another partial declaration of this type exists
CS0261 Error Partial declarations of '{0}' must be all classes, all structs, or all interfaces
CS0262 Error Partial declarations of '{0}' have conflicting accessibility modifiers
CS0263 Error Partial declarations of '{0}' must not specify different base classes
CS0264 Error Partial declarations of '{0}' must have the same type parameter names in the same order
CS0265 Error Partial declarations of '{0}' have inconsistent constraints for type parameter '{1}'
CS0266 Error Cannot implicitly convert type '{0}' to '{1}'. An explicit conversion exists (are you missing a cast?)
CS0267 Error The 'partial' modifier can only appear immediately before 'class', 'struct', 'interface', or 'void'
CS0268 Error Imported type '{0}' is invalid. It contains a circular base class dependency.
CS0269 Error Use of unassigned out parameter '{0}'
CS0270 Error Array size cannot be specified in a variable declaration (try initializing with a 'new' expression)
CS0271 Error The property or indexer '{0}' cannot be used in this context because the get accessor is inaccessible
CS0272 Error The property or indexer '{0}' cannot be used in this context because the set accessor is inaccessible
CS0273 Error The accessibility modifier of the '{0}' accessor must be more restrictive than the property or indexer '{1}'
CS0274 Error Cannot specify accessibility modifiers for both accessors of the property or indexer '{0}'
CS0276 Error '{0}': accessibility modifiers on accessors may only be used if the property or indexer has both a get and a set accessor
CS0277 Error '{0}' does not implement interface member '{1}'. '{2}' is not public.
CS0278 Warning '{0}' does not implement the '{1}' pattern. '{2}' is ambiguous with '{3}'.
CS0279 Warning '{0}' does not implement the '{1}' pattern. '{2}' is either static or not public.
CS0280 Warning '{0}' does not implement the '{1}' pattern. '{2}' has the wrong signature.
CS0281 Error Friend access was granted by '{0}', but the public key of the output assembly ('{1}') does not match that specified by the InternalsVisibleTo attribute in the granting assembly.
CS0282 Warning There is no defined ordering between fields in multiple declarations of partial struct '{0}'. To specify an ordering, all instance fields must be in the same declaration.
CS0283 Error The type '{0}' cannot be declared const
CS0304 Error Cannot create an instance of the variable type '{0}' because it does not have the new() constraint
CS0305 Error Using the generic {1} '{0}' requires {2} type arguments
CS0306 Error The type '{0}' may not be used as a type argument
CS0307 Error The {1} '{0}' cannot be used with type arguments
CS0308 Error The non-generic {1} '{0}' cannot be used with type arguments
CS0310 Error '{2}' must be a non-abstract type with a public parameterless constructor in order to use it as parameter '{1}' in the generic type or method '{0}'
CS0311 Error The type '{3}' cannot be used as type parameter '{2}' in the generic type or method '{0}'. There is no implicit reference conversion from '{3}' to '{1}'.
CS0312 Error The type '{3}' cannot be used as type parameter '{2}' in the generic type or method '{0}'. The nullable type '{3}' does not satisfy the constraint of '{1}'.
CS0313 Error The type '{3}' cannot be used as type parameter '{2}' in the generic type or method '{0}'. The nullable type '{3}' does not satisfy the constraint of '{1}'. Nullable types can not satisfy any interface constraints.
CS0314 Error The type '{3}' cannot be used as type parameter '{2}' in the generic type or method '{0}'. There is no boxing conversion or type parameter conversion from '{3}' to '{1}'.
CS0315 Error The type '{3}' cannot be used as type parameter '{2}' in the generic type or method '{0}'. There is no boxing conversion from '{3}' to '{1}'.
CS0316 Error The parameter name '{0}' conflicts with an automatically-generated parameter name
CS0400 Error The type or namespace name '{0}' could not be found in the global namespace (are you missing an assembly reference?)
CS0401 Error The new() constraint must be the last constraint specified
CS0402 Warning '{0}': an entry point cannot be generic or in a generic type
CS0403 Error Cannot convert null to type parameter '{0}' because it could be a non-nullable value type. Consider using 'default({0})' instead.
CS0404 Error Cannot apply attribute class '{0}' because it is generic
CS0405 Error Duplicate constraint '{0}' for type parameter '{1}'
CS0406 Error The class type constraint '{0}' must come before any other constraints
CS0407 Error '{1} {0}' has the wrong return type
CS0409 Error A constraint clause has already been specified for type parameter '{0}'. All of the constraints for a type parameter must be specified in a single where clause.
CS0411 Error The type arguments for method '{0}' cannot be inferred from the usage. Try specifying the type arguments explicitly.
CS0412 Error '{0}': a parameter, local variable, or local function cannot have the same name as a method type parameter
CS0413 Error The type parameter '{0}' cannot be used with the 'as' operator because it does not have a class type constraint nor a 'class' constraint
CS0414 Warning The field '{0}' is assigned but its value is never used
CS0415 Error The '{0}' attribute is valid only on an indexer that is not an explicit interface member declaration
CS0416 Error '{0}': an attribute argument cannot use type parameters
CS0417 Error '{0}': cannot provide arguments when creating an instance of a variable type
CS0418 Error '{0}': an abstract class cannot be sealed or static
CS0419 Warning Ambiguous reference in cref attribute: '{0}'. Assuming '{1}', but could have also matched other overloads including '{2}'.
CS0420 Warning '{0}': a reference to a volatile field will not be treated as volatile
CS0423 Error Since '{1}' has the ComImport attribute, '{0}' must be extern or abstract
CS0424 Error '{0}': a class with the ComImport attribute cannot specify a base class
CS0425 Error The constraints for type parameter '{0}' of method '{1}' must match the constraints for type parameter '{2}' of interface method '{3}'. Consider using an explicit interface implementation instead.
CS0426 Error The type name '{0}' does not exist in the type '{1}'
CS0428 Error Cannot convert method group '{0}' to non-delegate type '{1}'. Did you intend to invoke the method?
CS0430 Error The extern alias '{0}' was not specified in a /reference option
CS0431 Error Cannot use alias '{0}' with '::' since the alias references a type. Use '.' instead.
CS0432 Error Alias '{0}' not found
CS0433 Error The type '{1}' exists in both '{0}' and '{2}'
CS0434 Error The namespace '{1}' in '{0}' conflicts with the type '{3}' in '{2}'
CS0435 Warning The namespace '{1}' in '{0}' conflicts with the imported type '{3}' in '{2}'. Using the namespace defined in '{0}'.
CS0436 Warning The type '{1}' in '{0}' conflicts with the imported type '{3}' in '{2}'. Using the type defined in '{0}'.
CS0437 Warning The type '{1}' in '{0}' conflicts with the imported namespace '{3}' in '{2}'. Using the type defined in '{0}'.
CS0438 Error The type '{1}' in '{0}' conflicts with the namespace '{3}' in '{2}'
CS0439 Error An extern alias declaration must precede all other elements defined in the namespace
CS0440 Warning Defining an alias named 'global' is ill-advised since 'global::' always references the global namespace and not an alias
CS0441 Error '{0}': a class cannot be both static and sealed
CS0442 Error '{0}': abstract properties cannot have private accessors
CS0443 Error Syntax error; value expected
CS0445 Error Cannot modify the result of an unboxing conversion
CS0446 Error Foreach cannot operate on a '{0}'. Did you intend to invoke the '{0}'?
CS0448 Error The return type for ++ or -- operator must match the parameter type or be derived from the parameter type
CS0449 Error The 'class' or 'struct' constraint must come before any other constraints
CS0450 Error '{0}': cannot specify both a constraint class and the 'class' or 'struct' constraint
CS0451 Error The 'new()' constraint cannot be used with the 'struct' constraint
CS0452 Error The type '{2}' must be a reference type in order to use it as parameter '{1}' in the generic type or method '{0}'
CS0453 Error The type '{2}' must be a non-nullable value type in order to use it as parameter '{1}' in the generic type or method '{0}'
CS0454 Error Circular constraint dependency involving '{0}' and '{1}'
CS0455 Error Type parameter '{0}' inherits conflicting constraints '{1}' and '{2}'
CS0456 Error Type parameter '{1}' has the 'struct' constraint so '{1}' cannot be used as a constraint for '{0}'
CS0457 Error Ambiguous user defined conversions '{0}' and '{1}' when converting from '{2}' to '{3}'
CS0458 Warning The result of the expression is always 'null' of type '{0}'
CS0460 Error Constraints for override and explicit interface implementation methods are inherited from the base method, so they cannot be specified directly, except for either a 'class', or a 'struct' constraint.
CS0462 Error The inherited members '{0}' and '{1}' have the same signature in type '{2}', so they cannot be overridden
CS0463 Error Evaluation of the decimal constant expression failed
CS0464 Warning Comparing with null of type '{0}' always produces 'false'
CS0465 Warning Introducing a 'Finalize' method can interfere with destructor invocation. Did you intend to declare a destructor?
CS0466 Error '{0}' should not have a params parameter since '{1}' does not
CS0469 Warning The 'goto case' value is not implicitly convertible to type '{0}'
CS0470 Error Method '{0}' cannot implement interface accessor '{1}' for type '{2}'. Use an explicit interface implementation.
CS0472 Warning The result of the expression is always '{0}' since a value of type '{1}' is never equal to 'null' of type '{2}'
CS0473 Warning Explicit interface implementation '{0}' matches more than one interface member. Which interface member is actually chosen is implementation-dependent. Consider using a non-explicit implementation instead.
CS0500 Error '{0}' cannot declare a body because it is marked abstract
CS0501 Error '{0}' must declare a body because it is not marked abstract, extern, or partial
CS0502 Error '{0}' cannot be both abstract and sealed
CS0503 Error The abstract {0} '{1}' cannot be marked virtual
CS0504 Error The constant '{0}' cannot be marked static
CS0505 Error '{0}': cannot override because '{1}' is not a function
CS0506 Error '{0}': cannot override inherited member '{1}' because it is not marked virtual, abstract, or override
CS0507 Error '{0}': cannot change access modifiers when overriding '{1}' inherited member '{2}'
CS0508 Error '{0}': return type must be '{2}' to match overridden member '{1}'
CS0509 Error '{0}': cannot derive from sealed type '{1}'
CS0513 Error '{0}' is abstract but it is contained in non-abstract class '{1}'
CS0514 Error '{0}': static constructor cannot have an explicit 'this' or 'base' constructor call
CS0515 Error '{0}': access modifiers are not allowed on static constructors
CS0516 Error Constructor '{0}' cannot call itself
CS0517 Error '{0}' has no base class and cannot call a base constructor
CS0518 Error Predefined type '{0}' is not defined or imported
CS0522 Error '{0}': structs cannot call base class constructors
CS0523 Error Struct member '{0}' of type '{1}' causes a cycle in the struct layout
CS0525 Error Interfaces cannot contain instance fields
CS0526 Error Interfaces cannot contain instance constructors
CS0527 Error Type '{0}' in interface list is not an interface
CS0528 Error '{0}' is already listed in interface list
CS0529 Error Inherited interface '{1}' causes a cycle in the interface hierarchy of '{0}'
CS0533 Error '{0}' hides inherited abstract member '{1}'
CS0534 Error '{0}' does not implement inherited abstract member '{1}'
CS0535 Error '{0}' does not implement interface member '{1}'
CS0537 Error The class System.Object cannot have a base class or implement an interface
CS0538 Error '{0}' in explicit interface declaration is not an interface
CS0539 Error '{0}' in explicit interface declaration is not found among members of the interface that can be implemented
CS0540 Error '{0}': containing type does not implement interface '{1}'
CS0541 Error '{0}': explicit interface declaration can only be declared in a class, struct or interface
CS0542 Error '{0}': member names cannot be the same as their enclosing type
CS0543 Error '{0}': the enumerator value is too large to fit in its type
CS0544 Error '{0}': cannot override because '{1}' is not a property
CS0545 Error '{0}': cannot override because '{1}' does not have an overridable get accessor
CS0546 Error '{0}': cannot override because '{1}' does not have an overridable set accessor
CS0547 Error '{0}': property or indexer cannot have void type
CS0548 Error '{0}': property or indexer must have at least one accessor
CS0549 Error '{0}' is a new virtual member in sealed class '{1}'
CS0550 Error '{0}' adds an accessor not found in interface member '{1}'
CS0551 Error Explicit interface implementation '{0}' is missing accessor '{1}'
CS0552 Error '{0}': user-defined conversions to or from an interface are not allowed
CS0553 Error '{0}': user-defined conversions to or from a base class are not allowed
CS0554 Error '{0}': user-defined conversions to or from a derived class are not allowed
CS0555 Error User-defined operator cannot take an object of the enclosing type and convert to an object of the enclosing type
CS0556 Error User-defined conversion must convert to or from the enclosing type
CS0557 Error Duplicate user-defined conversion in type '{0}'
CS0558 Error User-defined operator '{0}' must be declared static and public
CS0559 Error The parameter type for ++ or -- operator must be the containing type
CS0562 Error The parameter of a unary operator must be the containing type
CS0563 Error One of the parameters of a binary operator must be the containing type
CS0564 Error The first operand of an overloaded shift operator must have the same type as the containing type, and the type of the second operand must be int
CS0567 Error Interfaces cannot contain conversion, equality, or inequality operators
CS0568 Error Structs cannot contain explicit parameterless constructors
CS0569 Error '{0}': cannot override '{1}' because it is not supported by the language
CS0570 Error '{0}' is not supported by the language
CS0571 Error '{0}': cannot explicitly call operator or accessor
CS0572 Error '{0}': cannot reference a type through an expression; try '{1}' instead
CS0573 Error '{0}': cannot have instance property or field initializers in structs
CS0574 Error Name of destructor must match name of class
CS0575 Error Only class types can contain destructors
CS0576 Error Namespace '{1}' contains a definition conflicting with alias '{0}'
CS0577 Error The Conditional attribute is not valid on '{0}' because it is a constructor, destructor, operator, or explicit interface implementation
CS0578 Error The Conditional attribute is not valid on '{0}' because its return type is not void
CS0579 Error Duplicate '{0}' attribute
CS0582 Error The Conditional attribute is not valid on interface members
CS0590 Error User-defined operators cannot return void
CS0591 Error Invalid value for argument to '{0}' attribute
CS0592 Error Attribute '{0}' is not valid on this declaration type. It is only valid on '{1}' declarations.
CS0594 Error Floating-point constant is outside the range of type '{0}'
CS0595 Error Invalid real literal.
CS0596 Error The Guid attribute must be specified with the ComImport attribute
CS0599 Error Invalid value for named attribute argument '{0}'
CS0601 Error The DllImport attribute must be specified on a method marked 'static' and 'extern'
CS0610 Error Field or property cannot be of type '{0}'
CS0611 Error Array elements cannot be of type '{0}'
CS0612 Warning '{0}' is obsolete
CS0616 Error '{0}' is not an attribute class
CS0617 Error '{0}' is not a valid named attribute argument. Named attribute arguments must be fields which are not readonly, static, or const, or read-write properties which are public and not static.
CS0618 Warning '{0}' is obsolete: '{1}'
CS0619 Error '{0}' is obsolete: '{1}'
CS0620 Error Indexers cannot have void type
CS0621 Error '{0}': virtual or abstract members cannot be private
CS0622 Error Can only use array initializer expressions to assign to array types. Try using a new expression instead.
CS0623 Error Array initializers can only be used in a variable or field initializer. Try using a new expression instead.
CS0625 Error '{0}': instance field in types marked with StructLayout(LayoutKind.Explicit) must have a FieldOffset attribute
CS0626 Warning Method, operator, or accessor '{0}' is marked external and has no attributes on it. Consider adding a DllImport attribute to specify the external implementation.
CS0628 Warning '{0}': new protected member declared in sealed class
CS0629 Error Conditional member '{0}' cannot implement interface member '{1}' in type '{2}'
CS0630 Error '{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter
CS0631 Error ref and out are not valid in this context
CS0633 Error The argument to the '{0}' attribute must be a valid identifier
CS0636 Error The FieldOffset attribute can only be placed on members of types marked with the StructLayout(LayoutKind.Explicit)
CS0637 Error The FieldOffset attribute is not allowed on static or const fields
CS0641 Error Attribute '{0}' is only valid on classes derived from System.Attribute
CS0642 Warning Possible mistaken empty statement
CS0643 Error '{0}' duplicate named attribute argument
CS0644 Error '{0}' cannot derive from special class '{1}'
CS0646 Error Cannot specify the DefaultMember attribute on a type containing an indexer
CS0648 Error '{0}' is a type not supported by the language
CS0649 Warning Field '{0}' is never assigned to, and will always have its default value {1}
CS0650 Error Bad array declarator: To declare a managed array the rank specifier precedes the variable's identifier. To declare a fixed size buffer field, use the fixed keyword before the field type.
CS0652 Warning Comparison to integral constant is useless; the constant is outside the range of type '{0}'
CS0653 Error Cannot apply attribute class '{0}' because it is abstract
CS0655 Error '{0}' is not a valid named attribute argument because it is not a valid attribute parameter type
CS0656 Error Missing compiler required member '{0}.{1}'
CS0657 Warning '{0}' is not a valid attribute location for this declaration. Valid attribute locations for this declaration are '{1}'. All attributes in this block will be ignored.
CS0658 Warning '{0}' is not a recognized attribute location. Valid attribute locations for this declaration are '{1}'. All attributes in this block will be ignored.
CS0659 Warning '{0}' overrides Object.Equals(object o) but does not override Object.GetHashCode()
CS0660 Warning '{0}' defines operator == or operator != but does not override Object.Equals(object o)
CS0661 Warning '{0}' defines operator == or operator != but does not override Object.GetHashCode()
CS0662 Error Cannot specify the Out attribute on a ref parameter without also specifying the In attribute.
CS0663 Error '{0}' cannot define an overloaded {1} that differs only on parameter modifiers '{2}' and '{3}'
CS0664 Error Literal of type double cannot be implicitly converted to type '{1}'; use an '{0}' suffix to create a literal of this type
CS0665 Warning Assignment in conditional expression is always constant; did you mean to use == instead of = ?
CS0666 Error '{0}': new protected member declared in struct
CS0668 Error Two indexers have different names; the IndexerName attribute must be used with the same name on every indexer within a type
CS0669 Error A class with the ComImport attribute cannot have a user-defined constructor
CS0670 Error Field cannot have void type
CS0672 Warning Member '{0}' overrides obsolete member '{1}'. Add the Obsolete attribute to '{0}'.
CS0673 Error System.Void cannot be used from C# -- use typeof(void) to get the void type object
CS0674 Error Do not use 'System.ParamArrayAttribute'. Use the 'params' keyword instead.
CS0675 Warning Bitwise-or operator used on a sign-extended operand; consider casting to a smaller unsigned type first
CS0677 Error '{0}': a volatile field cannot be of the type '{1}'
CS0678 Error '{0}': a field cannot be both volatile and readonly
CS0681 Error The modifier 'abstract' is not valid on fields. Try using a property instead.
CS0682 Error '{0}' cannot implement '{1}' because it is not supported by the language
CS0683 Error '{0}' explicit method implementation cannot implement '{1}' because it is an accessor
CS0684 Warning '{0}' interface marked with 'CoClassAttribute' not marked with 'ComImportAttribute'
CS0685 Error Conditional member '{0}' cannot have an out parameter
CS0686 Error Accessor '{0}' cannot implement interface member '{1}' for type '{2}'. Use an explicit interface implementation.
CS0687 Error The namespace alias qualifier '::' always resolves to a type or namespace so is illegal here. Consider using '.' instead.
CS0689 Error Cannot derive from '{0}' because it is a type parameter
CS0692 Error Duplicate type parameter '{0}'
CS0693 Warning Type parameter '{0}' has the same name as the type parameter from outer type '{1}'
CS0694 Error Type parameter '{0}' has the same name as the containing type, or method
CS0695 Error '{0}' cannot implement both '{1}' and '{2}' because they may unify for some type parameter substitutions
CS0698 Error A generic type cannot derive from '{0}' because it is an attribute class
CS0699 Error '{1}' does not define type parameter '{0}'
CS0701 Error '{0}' is not a valid constraint. A type used as a constraint must be an interface, a non-sealed class or a type parameter.
CS0702 Error Constraint cannot be special class '{0}'
CS0703 Error Inconsistent accessibility: constraint type '{1}' is less accessible than '{0}'
CS0704 Error Cannot do member lookup in '{0}' because it is a type parameter
CS0706 Error Invalid constraint type. A type used as a constraint must be an interface, a non-sealed class or a type parameter.
CS0708 Error '{0}': cannot declare instance members in a static class
CS0709 Error '{1}': cannot derive from static class '{0}'
CS0710 Error Static classes cannot have instance constructors
CS0711 Error Static classes cannot contain destructors
CS0712 Error Cannot create an instance of the static class '{0}'
CS0713 Error Static class '{0}' cannot derive from type '{1}'. Static classes must derive from object.
CS0714 Error '{0}': static classes cannot implement interfaces
CS0715 Error '{0}': static classes cannot contain user-defined operators
CS0716 Error Cannot convert to static type '{0}'
CS0717 Error '{0}': static classes cannot be used as constraints
CS0718 Error '{0}': static types cannot be used as type arguments
CS0719 Error '{0}': array elements cannot be of static type
CS0720 Error '{0}': cannot declare indexers in a static class
CS0721 Error '{0}': static types cannot be used as parameters
CS0722 Error '{0}': static types cannot be used as return types
CS0723 Error Cannot declare a variable of static type '{0}'
CS0724 Error A throw statement with no arguments is not allowed in a finally clause that is nested inside the nearest enclosing catch clause
CS0726 Error '{0}' is not a valid format specifier
CS0728 Warning Possibly incorrect assignment to local '{0}' which is the argument to a using or lock statement. The Dispose call or unlocking will happen on the original value of the local.
CS0729 Error Type '{0}' is defined in this assembly, but a type forwarder is specified for it
CS0730 Error Cannot forward type '{0}' because it is a nested type of '{1}'
CS0731 Error The type forwarder for type '{0}' in assembly '{1}' causes a cycle
CS0734 Error The /moduleassemblyname option may only be specified when building a target type of 'module'
CS0735 Error Invalid type specified as an argument for TypeForwardedTo attribute
CS0736 Error '{0}' does not implement interface member '{1}'. '{2}' cannot implement an interface member because it is static.
CS0737 Error '{0}' does not implement interface member '{1}'. '{2}' cannot implement an interface member because it is not public.
CS0738 Error '{0}' does not implement interface member '{1}'. '{2}' cannot implement '{1}' because it does not have the matching return type of '{3}'.
CS0739 Error '{0}' duplicate TypeForwardedToAttribute
CS0742 Error A query body must end with a select clause or a group clause
CS0743 Error Expected contextual keyword 'on'
CS0744 Error Expected contextual keyword 'equals'
CS0745 Error Expected contextual keyword 'by'
CS0746 Error Invalid anonymous type member declarator. Anonymous type members must be declared with a member assignment, simple name or member access.
CS0747 Error Invalid initializer member declarator
CS0748 Error Inconsistent lambda parameter usage; parameter types must be all explicit or all implicit
CS0750 Error A partial method cannot have access modifiers or the virtual, abstract, override, new, sealed, or extern modifiers
CS0751 Error A partial method must be declared within a partial class, partial struct, or partial interface
CS0752 Error A partial method cannot have out parameters
CS0754 Error A partial method may not explicitly implement an interface method
CS0755 Error Both partial method declarations must be extension methods or neither may be an extension method
CS0756 Error A partial method may not have multiple defining declarations
CS0757 Error A partial method may not have multiple implementing declarations
CS0758 Error Both partial method declarations must use a params parameter or neither may use a params parameter
CS0759 Error No defining declaration found for implementing declaration of partial method '{0}'
CS0761 Error Partial method declarations of '{0}' have inconsistent constraints for type parameter '{1}'
CS0762 Error Cannot create delegate from method '{0}' because it is a partial method without an implementing declaration
CS0763 Error Both partial method declarations must be static or neither may be static
CS0764 Error Both partial method declarations must be unsafe or neither may be unsafe
CS0765 Error Partial methods with only a defining declaration or removed conditional methods cannot be used in expression trees
CS0766 Error Partial methods must have a void return type
CS0767 Error Cannot inherit interface '{0}' with the specified type parameters because it causes method '{1}' to contain overloads which differ only on ref and out
CS0768 Error Constructor '{0}' cannot call itself through another constructor
CS0809 Warning Obsolete member '{0}' overrides non-obsolete member '{1}'
CS0811 Warning The fully qualified name for '{0}' is too long for debug information. Compile without '/debug' option.
CS0815 Error Cannot assign {0} to an implicitly-typed variable
CS0818 Error Implicitly-typed variables must be initialized
CS0819 Error Implicitly-typed variables cannot have multiple declarators
CS0820 Error Cannot initialize an implicitly-typed variable with an array initializer
CS0821 Error Implicitly-typed local variables cannot be fixed
CS0822 Error Implicitly-typed variables cannot be constant
CS0824 Warning Constructor '{0}' is marked external
CS0825 Error The contextual keyword 'var' may only appear within a local variable declaration or in script code
CS0826 Error No best type found for implicitly-typed array
CS0828 Error Cannot assign '{0}' to anonymous type property
CS0831 Error An expression tree may not contain a base access
CS0832 Error An expression tree may not contain an assignment operator
CS0833 Error An anonymous type cannot have multiple properties with the same name
CS0834 Error A lambda expression with a statement body cannot be converted to an expression tree
CS0835 Error Cannot convert lambda to an expression tree whose type argument '{0}' is not a delegate type
CS0836 Error Cannot use anonymous type in a constant expression
CS0837 Error The first operand of an 'is' or 'as' operator may not be a lambda expression, anonymous method, or method group.
CS0838 Error An expression tree may not contain a multidimensional array initializer
CS0839 Error Argument missing
CS0841 Error Cannot use local variable '{0}' before it is declared
CS0843 Error Auto-implemented property '{0}' must be fully assigned before control is returned to the caller.
CS0844 Error Cannot use local variable '{0}' before it is declared. The declaration of the local variable hides the field '{1}'.
CS0845 Error An expression tree lambda may not contain a coalescing operator with a null or default literal left-hand side
CS0846 Error A nested array initializer is expected
CS0847 Error An array initializer of length '{0}' is expected
CS0853 Error An expression tree may not contain a named argument specification
CS0854 Error An expression tree may not contain a call or invocation that uses optional arguments
CS0855 Error An expression tree may not contain an indexed property
CS0856 Error Indexed property '{0}' has non-optional arguments which must be provided
CS0857 Error Indexed property '{0}' must have all arguments optional
CS1001 Error Identifier expected
CS1002 Error ; expected
CS1003 Error Syntax error, '{0}' expected
CS1004 Error Duplicate '{0}' modifier
CS1007 Error Property accessor already defined
CS1008 Error Type byte, sbyte, short, ushort, int, uint, long, or ulong expected
CS1009 Error Unrecognized escape sequence
CS1010 Error Newline in constant
CS1011 Error Empty character literal
CS1012 Error Too many characters in character literal
CS1013 Error Invalid number
CS1014 Error A get or set accessor expected
CS1015 Error An object, string, or class type expected
CS1016 Error Named attribute argument expected
CS1017 Error Catch clauses cannot follow the general catch clause of a try statement
CS1018 Error Keyword 'this' or 'base' expected
CS1019 Error Overloadable unary operator expected
CS1020 Error Overloadable binary operator expected
CS1021 Error Integral constant is too large
CS1022 Error Type or namespace definition, or end-of-file expected
CS1023 Error Embedded statement cannot be a declaration or labeled statement
CS1024 Error Preprocessor directive expected
CS1025 Error Single-line comment or end-of-line expected
CS1026 Error ) expected
CS1027 Error #endif directive expected
CS1028 Error Unexpected preprocessor directive
CS1029 Error #error: '{0}'
CS1030 Warning #warning: '{0}'
CS1031 Error Type expected
CS1032 Error Cannot define/undefine preprocessor symbols after first token in file
CS1035 Error End-of-file found, '*/' expected
CS1037 Error Overloadable operator expected
CS1038 Error #endregion directive expected
CS1039 Error Unterminated string literal
CS1040 Error Preprocessor directives must appear as the first non-whitespace character on a line
CS1041 Error Identifier expected; '{1}' is a keyword
CS1043 Error { or ; expected
CS1044 Error Cannot use more than one type in a for, using, fixed, or declaration statement
CS1055 Error An add or remove accessor expected
CS1056 Error Unexpected character '{0}'
CS1057 Error '{0}': static classes cannot contain protected members
CS1058 Warning A previous catch clause already catches all exceptions. All non-exceptions thrown will be wrapped in a System.Runtime.CompilerServices.RuntimeWrappedException.
CS1059 Error The operand of an increment or decrement operator must be a variable, property or indexer
CS1061 Error '{0}' does not contain a definition for '{1}' and no accessible extension method '{1}' accepting a first argument of type '{0}' could be found (are you missing a using directive or an assembly reference?)
CS1062 Warning The best overloaded Add method '{0}' for the collection initializer element is obsolete. {1}
CS1063 Error The best overloaded Add method '{0}' for the collection initializer element is obsolete. {1}
CS1064 Warning The best overloaded Add method '{0}' for the collection initializer element is obsolete.
CS1065 Error Default values are not valid in this context.
CS1066 Warning The default value specified for parameter '{0}' will have no effect because it applies to a member that is used in contexts that do not allow optional arguments
CS1067 Error Partial declarations of '{0}' must have the same type parameter names and variance modifiers in the same order
CS1068 Error The type name '{0}' could not be found in the global namespace. This type has been forwarded to assembly '{1}' Consider adding a reference to that assembly.
CS1069 Error The type name '{0}' could not be found in the namespace '{1}'. This type has been forwarded to assembly '{2}' Consider adding a reference to that assembly.
CS1070 Error The type name '{0}' could not be found. This type has been forwarded to assembly '{1}'. Consider adding a reference to that assembly.
CS1072 Warning Expected identifier or numeric literal.
CS1073 Error Unexpected token '{0}'
CS1100 Error Method '{0}' has a parameter modifier 'this' which is not on the first parameter
CS1103 Error The first parameter of an extension method cannot be of type '{0}'
CS1104 Error A parameter array cannot be used with 'this' modifier on an extension method
CS1105 Error Extension method must be static
CS1106 Error Extension method must be defined in a non-generic static class
CS1107 Error A parameter can only have one '{0}' modifier
CS1109 Error Extension methods must be defined in a top level static class; {0} is a nested class
CS1110 Error Cannot define a new extension method because the compiler required type '{0}' cannot be found. Are you missing a reference to System.Core.dll?
CS1112 Error Do not use 'System.Runtime.CompilerServices.ExtensionAttribute'. Use the 'this' keyword instead.
CS1113 Error Extension method '{0}' defined on value type '{1}' cannot be used to create delegates
CS1501 Error No overload for method '{0}' takes {1} arguments
CS1503 Error Argument {0}: cannot convert from '{1}' to '{2}'
CS1504 Error Source file '{0}' could not be opened -- {1}
CS1507 Error Cannot link resource files when building a module
CS1508 Error Resource identifier '{0}' has already been used in this assembly
CS1509 Error The referenced file '{0}' is not an assembly
CS1510 Error A ref or out value must be an assignable variable
CS1511 Error Keyword 'base' is not available in a static method
CS1512 Error Keyword 'base' is not available in the current context
CS1513 Error } expected
CS1514 Error { expected
CS1515 Error 'in' expected
CS1517 Error Invalid preprocessor expression
CS1519 Error Invalid token '{0}' in class, struct, or interface member declaration
CS1520 Error Method must have a return type
CS1521 Error Invalid base type
CS1522 Warning Empty switch block
CS1524 Error Expected catch or finally
CS1525 Error Invalid expression term '{0}'
CS1526 Error A new expression requires (), [], or {} after type
CS1527 Error Elements defined in a namespace cannot be explicitly declared as private, protected, protected internal, or private protected
CS1528 Error Expected ; or = (cannot specify constructor arguments in declaration)
CS1529 Error A using clause must precede all other elements defined in the namespace except extern alias declarations
CS1534 Error Overloaded binary operator '{0}' takes two parameters
CS1535 Error Overloaded unary operator '{0}' takes one parameter
CS1536 Error Invalid parameter type 'void'
CS1537 Error The using alias '{0}' appeared previously in this namespace
CS1540 Error Cannot access protected member '{0}' via a qualifier of type '{1}'; the qualifier must be of type '{2}' (or derived from it)
CS1542 Error '{0}' cannot be added to this assembly because it already is an assembly
CS1545 Error Property, indexer, or event '{0}' is not supported by the language; try directly calling accessor methods '{1}' or '{2}'
CS1546 Error Property, indexer, or event '{0}' is not supported by the language; try directly calling accessor method '{1}'
CS1547 Error Keyword 'void' cannot be used in this context
CS1551 Error Indexers must have at least one parameter
CS1552 Error Array type specifier, [], must appear before parameter name
CS1553 Error Declaration is not valid; use '{0} operator (...' instead
CS1555 Error Could not find '{0}' specified for Main method
CS1556 Error '{0}' specified for Main method must be a non-generic class, struct, or interface
CS1558 Error '{0}' does not have a suitable static 'Main' method
CS1562 Error Outputs without source must have the /out option specified
CS1564 Error Conflicting options specified: Win32 resource file; Win32 manifest
CS1565 Error Conflicting options specified: Win32 resource file; Win32 icon
CS1566 Error Error reading resource '{0}' -- '{1}'
CS1569 Error Error writing to XML documentation file: {0}
CS1570 Warning XML comment has badly formed XML -- '{0}'
CS1571 Warning XML comment has a duplicate param tag for '{0}'
CS1572 Warning XML comment has a param tag for '{0}', but there is no parameter by that name
CS1573 Warning Parameter '{0}' has no matching param tag in the XML comment for '{1}' (but other parameters do)
CS1574 Warning XML comment has cref attribute '{0}' that could not be resolved
CS1575 Error A stackalloc expression requires [] after type
CS1576 Error The line number specified for #line directive is missing or invalid
CS1578 Error Quoted file name, single-line comment or end-of-line expected
CS1579 Error foreach statement cannot operate on variables of type '{0}' because '{0}' does not contain a public instance definition for '{1}'
CS1580 Warning Invalid type for parameter {0} in XML comment cref attribute: '{1}'
CS1581 Warning Invalid return type in XML comment cref attribute
CS1583 Error Error reading Win32 resources -- {0}
CS1584 Warning XML comment has syntactically incorrect cref attribute '{0}'
CS1585 Error Member modifier '{0}' must precede the member type and name
CS1586 Error Array creation must have array size or array initializer
CS1587 Warning XML comment is not placed on a valid language element
CS1589 Warning Unable to include XML fragment '{1}' of file '{0}' -- {2}
CS1590 Warning Invalid XML include element -- {0}
CS1591 Warning Missing XML comment for publicly visible type or member '{0}'
CS1592 Warning Badly formed XML in included comments file -- '{0}'
CS1593 Error Delegate '{0}' does not take {1} arguments
CS1597 Error Semicolon after method or accessor block is not valid
CS1599 Error Method or delegate cannot return type '{0}'
CS1600 Error Compilation cancelled by user
CS1601 Error Cannot make reference to variable of type '{0}'
CS1604 Error Cannot assign to '{0}' because it is read-only
CS1605 Error Cannot use '{0}' as a ref or out value because it is read-only
CS1607 Warning
CS1608 Error The RequiredAttribute attribute is not permitted on C# types
CS1609 Error Modifiers cannot be placed on event accessor declarations
CS1611 Error The params parameter cannot be declared as {0}
CS1612 Error Cannot modify the return value of '{0}' because it is not a variable
CS1613 Error The managed coclass wrapper class '{0}' for interface '{1}' cannot be found (are you missing an assembly reference?)
CS1614 Error '{0}' is ambiguous between '{1}' and '{2}'; use either '@{0}' or '{0}Attribute'
CS1615 Error Argument {0} may not be passed with the '{1}' keyword
CS1616 Warning Option '{0}' overrides attribute '{1}' given in a source file or added module
CS1617 Error Invalid option '{0}' for /langversion. Use '/langversion:?' to list supported values.
CS1618 Error Cannot create delegate with '{0}' because it or a method it overrides has a Conditional attribute
CS1619 Error Cannot create temporary file -- {0}
CS1620 Error Argument {0} must be passed with the '{1}' keyword
CS1621 Error The yield statement cannot be used inside an anonymous method or lambda expression
CS1622 Error Cannot return a value from an iterator. Use the yield return statement to return a value, or yield break to end the iteration.
CS1623 Error Iterators cannot have ref, in or out parameters
CS1624 Error The body of '{0}' cannot be an iterator block because '{1}' is not an iterator interface type
CS1625 Error Cannot yield in the body of a finally clause
CS1626 Error Cannot yield a value in the body of a try block with a catch clause
CS1627 Error Expression expected after yield return
CS1628 Error Cannot use ref, out, or in parameter '{0}' inside an anonymous method, lambda expression, query expression, or local function
CS1629 Error Unsafe code may not appear in iterators
CS1631 Error Cannot yield a value in the body of a catch clause
CS1632 Error Control cannot leave the body of an anonymous method or lambda expression
CS1633 Warning Unrecognized #pragma directive
CS1634 Warning Expected disable, restore or enable
CS1635 Warning Cannot restore warning 'CS{0}' because it was disabled globally
CS1636 Error __arglist is not allowed in the parameter list of iterators
CS1637 Error Iterators cannot have unsafe parameters or yield types
CS1639 Error The managed coclass wrapper class signature '{0}' for interface '{1}' is not a valid class name signature
CS1640 Error foreach statement cannot operate on variables of type '{0}' because it implements multiple instantiations of '{1}'; try casting to a specific interface instantiation
CS1641 Error A fixed size buffer field must have the array size specifier after the field name
CS1642 Error Fixed size buffer fields may only be members of structs
CS1643 Error Not all code paths return a value in {0} of type '{1}'
CS1645 Warning Feature '{0}' is not part of the standardized ISO C# language specification, and may not be accepted by other compilers
CS1646 Error Keyword, identifier, or string expected after verbatim specifier: @
CS1648 Error Members of readonly field '{0}' cannot be modified (except in a constructor or a variable initializer)
CS1649 Error Members of readonly field '{0}' cannot be used as a ref or out value (except in a constructor)
CS1650 Error Fields of static readonly field '{0}' cannot be assigned to (except in a static constructor or a variable initializer)
CS1651 Error Fields of static readonly field '{0}' cannot be used as a ref or out value (except in a static constructor)
CS1654 Error Cannot modify members of '{0}' because it is a '{1}'
CS1655 Error Cannot use fields of '{0}' as a ref or out value because it is a '{1}'
CS1656 Error Cannot assign to '{0}' because it is a '{1}'
CS1657 Error Cannot use '{0}' as a ref or out value because it is a '{1}'
CS1658 Warning {0}. See also error CS{1}.
CS1660 Error Cannot convert {0} to type '{1}' because it is not a delegate type
CS1661 Error Cannot convert {0} to type '{1}' because the parameter types do not match the delegate parameter types
CS1662 Error Cannot convert {0} to intended delegate type because some of the return types in the block are not implicitly convertible to the delegate return type
CS1663 Error Fixed size buffer type must be one of the following: bool, byte, short, int, long, char, sbyte, ushort, uint, ulong, float or double
CS1664 Error Fixed size buffer of length {0} and type '{1}' is too big
CS1665 Error Fixed size buffers must have a length greater than zero
CS1666 Error You cannot use fixed size buffers contained in unfixed expressions. Try using the fixed statement.
CS1667 Error Attribute '{0}' is not valid on property or event accessors. It is only valid on '{1}' declarations.
CS1668 Warning Invalid search path '{0}' specified in '{1}' -- '{2}'
CS1669 Error __arglist is not valid in this context
CS1670 Error params is not valid in this context
CS1671 Error A namespace declaration cannot have modifiers or attributes
CS1672 Error Invalid option '{0}' for /platform; must be anycpu, x86, Itanium, arm, arm64 or x64
CS1673 Error Anonymous methods, lambda expressions, and query expressions inside structs cannot access instance members of 'this'. Consider copying 'this' to a local variable outside the anonymous method, lambda expression or query expression and using the local instead.
CS1674 Error '{0}': type used in a using statement must be implicitly convertible to 'System.IDisposable' or implement a suitable 'Dispose' method.
CS1676 Error Parameter {0} must be declared with the '{1}' keyword
CS1677 Error Parameter {0} should not be declared with the '{1}' keyword
CS1678 Error Parameter {0} is declared as type '{1}{2}' but should be '{3}{4}'
CS1679 Error Invalid extern alias for '/reference'; '{0}' is not a valid identifier
CS1680 Error Invalid reference alias option: '{0}=' -- missing filename
CS1681 Error You cannot redefine the global extern alias
CS1685 Warning The predefined type '{0}' is defined in multiple assemblies in the global alias; using definition from '{1}'
CS1686 Error Local '{0}' or its members cannot have their address taken and be used inside an anonymous method or lambda expression
CS1687 Warning Source file has exceeded the limit of 16,707,565 lines representable in the PDB; debug information will be incorrect
CS1688 Error Cannot convert anonymous method block without a parameter list to delegate type '{0}' because it has one or more out parameters
CS1689 Error Attribute '{0}' is only valid on methods or attribute classes
CS1690 Warning Accessing a member on '{0}' may cause a runtime exception because it is a field of a marshal-by-reference class
CS1692 Warning Invalid number
CS1695 Warning Invalid #pragma checksum syntax; should be #pragma checksum "filename" "{XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}" "XXXX..."
CS1696 Warning Single-line comment or end-of-line expected
CS1697 Warning Different checksum values given for '{0}'
CS1700 Warning Assembly reference '{0}' is invalid and cannot be resolved
CS1701 Warning Assuming assembly reference '{0}' used by '{1}' matches identity '{2}' of '{3}', you may need to supply runtime policy
CS1702 Warning Assuming assembly reference '{0}' used by '{1}' matches identity '{2}' of '{3}', you may need to supply runtime policy
CS1703 Error Multiple assemblies with equivalent identity have been imported: '{0}' and '{1}'. Remove one of the duplicate references.
CS1704 Error An assembly with the same simple name '{0}' has already been imported. Try removing one of the references (e.g. '{1}') or sign them to enable side-by-side.
CS1705 Error Assembly '{0}' with identity '{1}' uses '{2}' which has a higher version than referenced assembly '{3}' with identity '{4}'
CS1708 Error Fixed size buffers can only be accessed through locals or fields
CS1710 Warning XML comment has a duplicate typeparam tag for '{0}'
CS1711 Warning XML comment has a typeparam tag for '{0}', but there is no type parameter by that name
CS1712 Warning Type parameter '{0}' has no matching typeparam tag in the XML comment on '{1}' (but other type parameters do)
CS1715 Error '{0}': type must be '{2}' to match overridden member '{1}'
CS1716 Error Do not use 'System.Runtime.CompilerServices.FixedBuffer' attribute. Use the 'fixed' field modifier instead.
CS1717 Warning Assignment made to same variable; did you mean to assign something else?
CS1718 Warning Comparison made to same variable; did you mean to compare something else?
CS1719 Error Error opening Win32 resource file '{0}' -- '{1}'
CS1720 Warning Expression will always cause a System.NullReferenceException because the default value of '{0}' is null
CS1721 Error Class '{0}' cannot have multiple base classes: '{1}' and '{2}'
CS1722 Error Base class '{0}' must come before any interfaces
CS1723 Warning XML comment has cref attribute '{0}' that refers to a type parameter
CS1725 Error Friend assembly reference '{0}' is invalid. InternalsVisibleTo declarations cannot have a version, culture, public key token, or processor architecture specified.
CS1726 Error Friend assembly reference '{0}' is invalid. Strong-name signed assemblies must specify a public key in their InternalsVisibleTo declarations.
CS1728 Error Cannot bind delegate to '{0}' because it is a member of 'System.Nullable'
CS1729 Error '{0}' does not contain a constructor that takes {1} arguments
CS1730 Error Assembly and module attributes must precede all other elements defined in a file except using clauses and extern alias declarations
CS1733 Error Expected expression
CS1734 Warning XML comment on '{1}' has a paramref tag for '{0}', but there is no parameter by that name
CS1735 Warning XML comment on '{1}' has a typeparamref tag for '{0}', but there is no type parameter by that name
CS1736 Error Default parameter value for '{0}' must be a compile-time constant
CS1737 Error Optional parameters must appear after all required parameters
CS1738 Error Named argument specifications must appear after all fixed arguments have been specified. Please use language version {0} or greater to allow non-trailing named arguments.
CS1739 Error The best overload for '{0}' does not have a parameter named '{1}'
CS1740 Error Named argument '{0}' cannot be specified multiple times
CS1741 Error A ref or out parameter cannot have a default value
CS1742 Error An array access may not have a named argument specifier
CS1743 Error Cannot specify a default value for the 'this' parameter
CS1744 Error Named argument '{0}' specifies a parameter for which a positional argument has already been given
CS1745 Error Cannot specify default parameter value in conjunction with DefaultParameterAttribute or OptionalAttribute
CS1746 Error The delegate '{0}' does not have a parameter named '{1}'
CS1747 Error Cannot embed interop types from assembly '{0}' because it is missing the '{1}' attribute.
CS1748 Error Cannot find the interop type that matches the embedded interop type '{0}'. Are you missing an assembly reference?
CS1750 Error A value of type '{0}' cannot be used as a default parameter because there are no standard conversions to type '{1}'
CS1751 Error Cannot specify a default value for a parameter array
CS1752 Error Interop type '{0}' cannot be embedded. Use the applicable interface instead.
CS1754 Error Type '{0}' cannot be embedded because it is a nested type. Consider setting the 'Embed Interop Types' property to false.
CS1756 Error Interop type '{0}' cannot be embedded because it is missing the required '{1}' attribute.
CS1757 Error Embedded interop struct '{0}' can contain only public instance fields.
CS1758 Error Cannot embed interop type '{0}' found in both assembly '{1}' and '{2}'. Consider setting the 'Embed Interop Types' property to false.
CS1759 Error Cannot embed interop types from assembly '{0}' because it is missing either the '{1}' attribute or the '{2}' attribute.
CS1760 Error Assemblies '{0}' and '{1}' refer to the same metadata but only one is a linked reference (specified using /link option); consider removing one of the references.
CS1761 Error Embedding the interop type '{0}' from assembly '{1}' causes a name clash in the current assembly. Consider setting the 'Embed Interop Types' property to false.
CS1762 Warning A reference was created to embedded interop assembly '{0}' because of an indirect reference to that assembly created by assembly '{1}'. Consider changing the 'Embed Interop Types' property on either assembly.
CS1763 Error '{0}' is of type '{1}'. A default parameter value of a reference type other than string can only be initialized with null
CS1764 Error Cannot use fixed local '{0}' inside an anonymous method, lambda expression, or query expression
CS1766 Error Source interface '{0}' is missing method '{1}' which is required to embed event '{2}'.
CS1767 Error Interface '{0}' has an invalid source interface which is required to embed event '{1}'.
CS1768 Error Type '{0}' cannot be embedded because it has a generic argument. Consider setting the 'Embed Interop Types' property to false.
CS1769 Error Type '{0}' from assembly '{1}' cannot be used across assembly boundaries because it has a generic type argument that is an embedded interop type.
CS1770 Error A value of type '{0}' cannot be used as default parameter for nullable parameter '{1}' because '{0}' is not a simple type
CS1773 Error Invalid version {0} for /subsystemversion. The version must be 6.02 or greater for ARM or AppContainerExe, and 4.00 or greater otherwise
CS1774 Error Embedded interop method '{0}' contains a body.
CS1900 Error Warning level must be in the range 0-4
CS1902 Error Invalid option '{0}' for /debug; must be 'portable', 'embedded', 'full' or 'pdbonly'
CS1906 Error Invalid option '{0}'; Resource visibility must be either 'public' or 'private'
CS1908 Error The type of the argument to the DefaultParameterValue attribute must match the parameter type
CS1910 Error Argument of type '{0}' is not applicable for the DefaultParameterValue attribute
CS1912 Error Duplicate initialization of member '{0}'
CS1913 Error Member '{0}' cannot be initialized. It is not a field or property.
CS1914 Error Static field or property '{0}' cannot be assigned in an object initializer
CS1917 Error Members of readonly field '{0}' of type '{1}' cannot be assigned with an object initializer because it is of a value type
CS1918 Error Members of property '{0}' of type '{1}' cannot be assigned with an object initializer because it is of a value type
CS1919 Error Unsafe type '{0}' cannot be used in object creation
CS1920 Error Element initializer cannot be empty
CS1921 Error The best overloaded method match for '{0}' has wrong signature for the initializer element. The initializable Add must be an accessible instance method.
CS1922 Error Cannot initialize type '{0}' with a collection initializer because it does not implement 'System.Collections.IEnumerable'
CS1926 Error Error opening Win32 manifest file {0} -- {1}
CS1927 Warning Ignoring /win32manifest for module because it only applies to assemblies
CS1929 Error '{0}' does not contain a definition for '{1}' and the best extension method overload '{2}' requires a receiver of type '{3}'
CS1930 Error The range variable '{0}' has already been declared
CS1931 Error The range variable '{0}' conflicts with a previous declaration of '{0}'
CS1932 Error Cannot assign {0} to a range variable
CS1934 Error Could not find an implementation of the query pattern for source type '{0}'. '{1}' not found. Consider explicitly specifying the type of the range variable '{2}'.
CS1935 Error Could not find an implementation of the query pattern for source type '{0}'. '{1}' not found. Are you missing a reference to 'System.Core.dll' or a using directive for 'System.Linq'?
CS1936 Error Could not find an implementation of the query pattern for source type '{0}'. '{1}' not found.
CS1937 Error The name '{0}' is not in scope on the left side of 'equals'. Consider swapping the expressions on either side of 'equals'.
CS1938 Error The name '{0}' is not in scope on the right side of 'equals'. Consider swapping the expressions on either side of 'equals'.
CS1939 Error Cannot pass the range variable '{0}' as an out or ref parameter
CS1940 Error Multiple implementations of the query pattern were found for source type '{0}'. Ambiguous call to '{1}'.
CS1941 Error The type of one of the expressions in the {0} clause is incorrect. Type inference failed in the call to '{1}'.
CS1942 Error The type of the expression in the {0} clause is incorrect. Type inference failed in the call to '{1}'.
CS1943 Error An expression of type '{0}' is not allowed in a subsequent from clause in a query expression with source type '{1}'. Type inference failed in the call to '{2}'.
CS1944 Error An expression tree may not contain an unsafe pointer operation
CS1945 Error An expression tree may not contain an anonymous method expression
CS1946 Error An anonymous method expression cannot be converted to an expression tree
CS1947 Error Range variable '{0}' cannot be assigned to -- it is read only
CS1948 Error The range variable '{0}' cannot have the same name as a method type parameter
CS1949 Error The contextual keyword 'var' cannot be used in a range variable declaration
CS1950 Error The best overloaded Add method '{0}' for the collection initializer has some invalid arguments
CS1951 Error An expression tree lambda may not contain a ref, in or out parameter
CS1952 Error An expression tree lambda may not contain a method with variable arguments
CS1954 Error The best overloaded method match '{0}' for the collection initializer element cannot be used. Collection initializer 'Add' methods cannot have ref or out parameters.
CS1955 Error Non-invocable member '{0}' cannot be used like a method.
CS1956 Warning Member '{0}' implements interface member '{1}' in type '{2}'. There are multiple matches for the interface member at run-time. It is implementation dependent which method will be called.
CS1957 Warning Member '{1}' overrides '{0}'. There are multiple override candidates at run-time. It is implementation dependent which method will be called.
CS1958 Error Object and collection initializer expressions may not be applied to a delegate creation expression
CS1959 Error '{0}' is of type '{1}'. The type specified in a constant declaration must be sbyte, byte, short, ushort, int, uint, long, ulong, char, float, double, decimal, bool, string, an enum-type, or a reference-type.
CS1960 Error Invalid variance modifier. Only interface and delegate type parameters can be specified as variant.
CS1961 Error Invalid variance: The type parameter '{1}' must be {3} valid on '{0}'. '{1}' is {2}.
CS1962 Error The typeof operator cannot be used on the dynamic type
CS1963 Error An expression tree may not contain a dynamic operation
CS1964 Error '{0}': user-defined conversions to or from the dynamic type are not allowed
CS1965 Error '{0}': cannot derive from the dynamic type
CS1966 Error '{0}': cannot implement a dynamic interface '{1}'
CS1967 Error Constraint cannot be the dynamic type
CS1968 Error Constraint cannot be a dynamic type '{0}'
CS1969 Error One or more types required to compile a dynamic expression cannot be found. Are you missing a reference?
CS1970 Error Do not use 'System.Runtime.CompilerServices.DynamicAttribute'. Use the 'dynamic' keyword instead.
CS1971 Error The call to method '{0}' needs to be dynamically dispatched, but cannot be because it is part of a base access expression. Consider casting the dynamic arguments or eliminating the base access.
CS1972 Error The indexer access needs to be dynamically dispatched, but cannot be because it is part of a base access expression. Consider casting the dynamic arguments or eliminating the base access.
CS1973 Error '{0}' has no applicable method named '{1}' but appears to have an extension method by that name. Extension methods cannot be dynamically dispatched. Consider casting the dynamic arguments or calling the extension method without the extension method syntax.
CS1974 Warning The dynamically dispatched call to method '{0}' may fail at runtime because one or more applicable overloads are conditional methods.
CS1975 Error The constructor call needs to be dynamically dispatched, but cannot be because it is part of a constructor initializer. Consider casting the dynamic arguments.
CS1976 Error Cannot use a method group as an argument to a dynamically dispatched operation. Did you intend to invoke the method?
CS1977 Error Cannot use a lambda expression as an argument to a dynamically dispatched operation without first casting it to a delegate or expression tree type.
CS1978 Error Cannot use an expression of type '{0}' as an argument to a dynamically dispatched operation.
CS1979 Error Query expressions over source type 'dynamic' or with a join sequence of type 'dynamic' are not allowed
CS1980 Error Cannot define a class or member that utilizes 'dynamic' because the compiler required type '{0}' cannot be found. Are you missing a reference?
CS1981 Warning Using '{0}' to test compatibility with '{1}' is essentially identical to testing compatibility with '{2}' and will succeed for all non-null values
CS1983 Error The return type of an async method must be void, Task, Task, a task-like type, IAsyncEnumerable, or IAsyncEnumerator
CS1984 Error Cannot await in the body of a finally clause
CS1985 Error Cannot await in a catch clause
CS1986 Error 'await' requires that the type {0} have a suitable 'GetAwaiter' method
CS1988 Error Async methods cannot have ref, in or out parameters
CS1989 Error Async lambda expressions cannot be converted to expression trees
CS1991 Error '{0}' cannot implement '{1}' because '{2}' is a Windows Runtime event and '{3}' is a regular .NET event.
CS1992 Error The 'await' operator can only be used when contained within a method or lambda expression marked with the 'async' modifier
CS1994 Error The 'async' modifier can only be used in methods that have a body.
CS1995 Error The 'await' operator may only be used in a query expression within the first collection expression of the initial 'from' clause or within the collection expression of a 'join' clause
CS1996 Error Cannot await in the body of a lock statement
CS1997 Error Since '{0}' is an async method that returns 'Task', a return keyword must not be followed by an object expression. Did you intend to return 'Task'?
CS1998 Warning This async method lacks 'await' operators and will run synchronously. Consider using the 'await' operator to await non-blocking API calls, or 'await Task.Run(...)' to do CPU-bound work on a background thread.
CS2001 Error Source file '{0}' could not be found.
CS2002 Warning Source file '{0}' specified multiple times
CS2005 Error Missing file specification for '{0}' option
CS2006 Error Command-line syntax error: Missing '{0}' for '{1}' option
CS2007 Error Unrecognized option: '{0}'
CS2008 Warning No source files specified.
CS2011 Error Error opening response file '{0}'
CS2012 Error Cannot open '{0}' for writing -- '{1}'
CS2013 Error Invalid image base number '{0}'
CS2015 Error '{0}' is a binary file instead of a text file
CS2016 Fatal Code page '{0}' is invalid or not installed
CS2017 Error Cannot specify /main if building a module or library
CS2019 Fatal Invalid target type for /target: must specify 'exe', 'winexe', 'library', or 'module'
CS2021 Fatal File name '{0}' is empty, contains invalid characters, has a drive specification without an absolute path, or is too long
CS2023 Warning Ignoring /noconfig option because it was specified in a response file
CS2024 Error Invalid file section alignment '{0}'
CS2029 Warning Invalid name for a preprocessing symbol; '{0}' is not a valid identifier
CS2033 Fatal Cannot create short filename '{0}' when a long filename with the same short filename already exists
CS2034 Error A /reference option that declares an extern alias can only have one filename. To specify multiple aliases or filenames, use multiple /reference options.
CS2035 Error Command-line syntax error: Missing ':' for '{0}' option
CS2036 Error The /pdb option requires that the /debug option also be used
CS2037 Error An expression tree lambda may not contain a COM call with ref omitted on arguments
CS2038 Warning The language name '{0}' is invalid.
CS2039 Error Command-line syntax error: Invalid Guid format '{0}' for option '{1}'
CS2040 Error Command-line syntax error: Missing Guid for option '{1}'
CS2041 Error Invalid output name: {0}
CS2042 Error Invalid debug information format: {0}
CS2043 Error 'id#' syntax is no longer supported. Use '$id' instead.
CS2044 Error /sourcelink switch is only supported when emitting PDB.
CS2045 Error /embed switch is only supported when emitting a PDB.
CS3000 Warning Methods with variable arguments are not CLS-compliant
CS3001 Warning Argument type '{0}' is not CLS-compliant
CS3002 Warning Return type of '{0}' is not CLS-compliant
CS3003 Warning Type of '{0}' is not CLS-compliant
CS3005 Warning Identifier '{0}' differing only in case is not CLS-compliant
CS3006 Warning Overloaded method '{0}' differing only in ref or out, or in array rank, is not CLS-compliant
CS3007 Warning Overloaded method '{0}' differing only by unnamed array types is not CLS-compliant
CS3008 Warning Identifier '{0}' is not CLS-compliant
CS3009 Warning '{0}': base type '{1}' is not CLS-compliant
CS3010 Warning '{0}': CLS-compliant interfaces must have only CLS-compliant members
CS3011 Warning '{0}': only CLS-compliant members can be abstract
CS3012 Warning You must specify the CLSCompliant attribute on the assembly, not the module, to enable CLS compliance checking
CS3013 Warning Added modules must be marked with the CLSCompliant attribute to match the assembly
CS3014 Warning '{0}' cannot be marked as CLS-compliant because the assembly does not have a CLSCompliant attribute
CS3015 Warning '{0}' has no accessible constructors which use only CLS-compliant types
CS3016 Warning Arrays as attribute arguments is not CLS-compliant
CS3017 Warning You cannot specify the CLSCompliant attribute on a module that differs from the CLSCompliant attribute on the assembly
CS3018 Warning '{0}' cannot be marked as CLS-compliant because it is a member of non-CLS-compliant type '{1}'
CS3019 Warning CLS compliance checking will not be performed on '{0}' because it is not visible from outside this assembly
CS3021 Warning '{0}' does not need a CLSCompliant attribute because the assembly does not have a CLSCompliant attribute
CS3022 Warning CLSCompliant attribute has no meaning when applied to parameters. Try putting it on the method instead.
CS3023 Warning CLSCompliant attribute has no meaning when applied to return types. Try putting it on the method instead.
CS3024 Warning Constraint type '{0}' is not CLS-compliant
CS3026 Warning CLS-compliant field '{0}' cannot be volatile
CS3027 Warning '{0}' is not CLS-compliant because base interface '{1}' is not CLS-compliant
CS3028 Fatal Algorithm '{0}' is not supported
CS4001 Error Cannot await '{0}'
CS4003 Error 'await' cannot be used as an identifier within an async method or lambda expression
CS4004 Error Cannot await in an unsafe context
CS4005 Error Async methods cannot have unsafe parameters or return types
CS4006 Error __arglist is not allowed in the parameter list of async methods
CS4007 Error 'await' cannot be used in an expression containing the type '{0}'
CS4008 Error Cannot await 'void'
CS4009 Error A void or int returning entry point cannot be async
CS4010 Error Cannot convert async {0} to delegate type '{1}'. An async {0} may return void, Task or Task, none of which are convertible to '{1}'.
CS4011 Error 'await' requires that the return type '{0}' of '{1}.GetAwaiter()' have suitable 'IsCompleted', 'OnCompleted', and 'GetResult' members, and implement 'INotifyCompletion' or 'ICriticalNotifyCompletion'
CS4012 Error Parameters or locals of type '{0}' cannot be declared in async methods or lambda expressions.
CS4013 Error Instance of type '{0}' cannot be used inside a nested function, query expression, iterator block or async method
CS4014 Warning Because this call is not awaited, execution of the current method continues before the call is completed. Consider applying the 'await' operator to the result of the call.
CS4015 Error 'MethodImplOptions.Synchronized' cannot be applied to an async method
CS4016 Error Since this is an async method, the return expression must be of type '{0}' rather than 'Task<{0}>'
CS4017 Error CallerLineNumberAttribute cannot be applied because there are no standard conversions from type '{0}' to type '{1}'
CS4018 Error CallerFilePathAttribute cannot be applied because there are no standard conversions from type '{0}' to type '{1}'
CS4019 Error CallerMemberNameAttribute cannot be applied because there are no standard conversions from type '{0}' to type '{1}'
CS4020 Error The CallerLineNumberAttribute may only be applied to parameters with default values
CS4021 Error The CallerFilePathAttribute may only be applied to parameters with default values
CS4022 Error The CallerMemberNameAttribute may only be applied to parameters with default values
CS4023 Error /platform:anycpu32bitpreferred can only be used with /t:exe, /t:winexe and /t:appcontainerexe
CS4024 Warning The CallerLineNumberAttribute applied to parameter '{0}' will have no effect because it applies to a member that is used in contexts that do not allow optional arguments
CS4025 Warning The CallerFilePathAttribute applied to parameter '{0}' will have no effect because it applies to a member that is used in contexts that do not allow optional arguments
CS4026 Warning The CallerMemberNameAttribute applied to parameter '{0}' will have no effect because it applies to a member that is used in contexts that do not allow optional arguments
CS4027 Error '{0}' does not implement '{1}'
CS4028 Error 'await' requires that the type '{0}' have a suitable 'GetAwaiter' method. Are you missing a using directive for 'System'?
CS4029 Error Cannot return an expression of type 'void'
CS4030 Error Security attribute '{0}' cannot be applied to an Async method.
CS4031 Error Async methods are not allowed in an Interface, Class, or Structure which has the 'SecurityCritical' or 'SecuritySafeCritical' attribute.
CS4032 Error The 'await' operator can only be used within an async method. Consider marking this method with the 'async' modifier and changing its return type to 'Task<{0}>'.
CS4033 Error The 'await' operator can only be used within an async method. Consider marking this method with the 'async' modifier and changing its return type to 'Task'.
CS4034 Error The 'await' operator can only be used within an async {0}. Consider marking this {0} with the 'async' modifier.
CS4036 Error '{0}' does not contain a definition for '{1}' and no extension method '{1}' accepting a first argument of type '{0}' could be found (are you missing a using directive for '{2}'?)
CS5001 Error Program does not contain a static 'Main' method suitable for an entry point
CS7000 Error Unexpected use of an aliased name
CS7002 Error Unexpected use of a generic name
CS7003 Error Unexpected use of an unbound generic name
CS7006 Error Expressions and statements can only occur in a method body
CS7007 Error A 'using static' directive can only be applied to types; '{0}' is a namespace not a type. Consider a 'using namespace' directive instead
CS7008 Error The assembly name '{0}' is reserved and cannot be used as a reference in an interactive session
CS7009 Error Cannot use #r after first token in file
CS7010 Error Quoted file name expected
CS7011 Error #r is only allowed in scripts
CS7012 Error The name '{0}' does not exist in the current context (are you missing a reference to assembly '{1}'?)
CS7013 Error Name '{0}' exceeds the maximum length allowed in metadata.
CS7014 Error Attributes are not valid in this context.
CS7015 Error 'extern alias' is not valid in this context
CS7016 Error Alias '{0}' conflicts with {1} definition
CS7017 Error Member definition, statement, or end-of-file expected
CS7018 Error Expected a script (.csx file) but none specified
CS7019 Error Type of '{0}' cannot be inferred since its initializer directly or indirectly refers to the definition.
CS7020 Error Cannot use 'yield' in top-level script code
CS7021 Error Cannot declare namespace in script code
CS7022 Warning The entry point of the program is global script code; ignoring '{0}' entry point.
CS7023 Error The second operand of an 'is' or 'as' operator may not be static type '{0}'
CS7024 Error Delegate '{0}' has no invoke method or an invoke method with a return type or parameter types that are not supported.
CS7025 Error Inconsistent accessibility: event type '{1}' is less accessible than event '{0}'
CS7026 Error Assembly and module attributes are not allowed in this context
CS7027 Error Error signing output with public key from file '{0}' -- {1}
CS7028 Error Error signing output with public key from container '{0}' -- {1}
CS7029 Error Friend access was granted by '{0}', but the strong name signing state of the output assembly does not match that of the granting assembly.
CS7030 Error Cannot pass null for friend assembly name
CS7032 Error Key file '{0}' is missing the private key needed for signing
CS7033 Warning Delay signing was specified and requires a public key, but no public key was specified
CS7034 Error The specified version string does not conform to the required format - major[.minor[.build[.revision]]]
CS7035 Warning The specified version string does not conform to the recommended format - major.minor.build.revision
CS7036 Error There is no argument given that corresponds to the required formal parameter '{0}' of '{1}'
CS7038 Error Failed to emit module '{0}'.
CS7041 Error Each linked resource and module must have a unique filename. Filename '{0}' is specified more than once in this assembly
CS7042 Error The DllImport attribute cannot be applied to a method that is generic or contained in a generic type.
CS7043 Error Cannot update '{0}'; attribute '{1}' is missing.
CS7045 Error Parameter not valid for the specified unmanaged type.
CS7046 Error Attribute parameter '{0}' must be specified.
CS7047 Error Attribute parameter '{0}' or '{1}' must be specified.
CS7048 Error First argument to a security attribute must be a valid SecurityAction
CS7049 Error Security attribute '{0}' has an invalid SecurityAction value '{1}'
CS7050 Error SecurityAction value '{0}' is invalid for security attributes applied to an assembly
CS7051 Error SecurityAction value '{0}' is invalid for security attributes applied to a type or a method
CS7052 Error SecurityAction value '{0}' is invalid for PrincipalPermission attribute
CS7053 Error An expression tree may not contain '{0}'
CS7054 Error Unmanaged type '{0}' not valid for fields.
CS7055 Error Unmanaged type '{0}' is only valid for fields.
CS7056 Error Unable to resolve file path '{0}' specified for the named argument '{1}' for PermissionSet attribute
CS7057 Error Error reading file '{0}' specified for the named argument '{1}' for PermissionSet attribute: '{2}'
CS7058 Error The specified version string does not conform to the required format - major.minor.build.revision (without wildcards)
CS7059 Error Executables cannot be satellite assemblies; culture should always be empty
CS7061 Error Duplicate '{0}' attribute in '{1}'
CS7064 Error Error opening icon file {0} -- {1}
CS7065 Error Error building Win32 resources -- {0}
CS7066 Error Yield statements may not appear at the top level in interactive code.
CS7067 Error Attribute constructor parameter '{0}' is optional, but no default parameter value was specified.
CS7068 Error Reference to type '{0}' claims it is defined in this assembly, but it is not defined in source or any added modules
CS7069 Error Reference to type '{0}' claims it is defined in '{1}', but it could not be found
CS7070 Error Security attribute '{0}' is not valid on this declaration type. Security attributes are only valid on assembly, type and method declarations.
CS7071 Error Assembly reference '{0}' is invalid and cannot be resolved
CS7079 Error The type '{0}' is defined in a module that has not been added. You must add the module '{1}'.
CS7080 Warning The CallerMemberNameAttribute applied to parameter '{0}' will have no effect. It is overridden by the CallerFilePathAttribute.
CS7081 Warning The CallerMemberNameAttribute applied to parameter '{0}' will have no effect. It is overridden by the CallerLineNumberAttribute.
CS7082 Warning The CallerFilePathAttribute applied to parameter '{0}' will have no effect. It is overridden by the CallerLineNumberAttribute.
CS7083 Error Expression must be implicitly convertible to Boolean or its type '{0}' must define operator '{1}'.
CS7084 Error A Windows Runtime event may not be passed as an out or ref parameter.
CS7085 Error By-reference return type 'ref {0}' is not supported.
CS7086 Error Module name '{0}' stored in '{1}' must match its filename.
CS7087 Error Invalid module name: {0}
CS7088 Error Invalid '{0}' value: '{1}'.
CS7089 Error AppConfigPath must be absolute.
CS7090 Warning Attribute '{0}' from module '{1}' will be ignored in favor of the instance appearing in source
CS7091 Error Attribute '{0}' given in a source file conflicts with option '{1}'.
CS7092 Error A fixed buffer may only have one dimension.
CS7093 Error Cannot read config file '{0}' -- '{1}'
CS7094 Error Cannot await in the filter expression of a catch clause
CS7095 Warning Filter expression is a constant 'true', consider removing the filter
CS7096 Error Cannot continue since the edit includes a reference to an embedded type: '{0}'.
CS7098 Error Linked netmodule metadata must provide a full PE image: '{0}'.
CS7099 Error Metadata references are not supported.
CS7100 Error Assembly culture strings may not contain embedded NUL characters.
CS7101 Error Member '{0}' added during the current debug session can only be accessed from within its declaring assembly '{1}'.
CS7102 Error Compilation options '{0}' and '{1}' can't both be specified at the same time.
CS7103 Error Unable to read debug information of method '{0}' (token 0x{1:X8}) from assembly '{2}'
CS8001 Warning The command line switch '{0}' is not yet implemented and was ignored.
CS8002 Warning Referenced assembly '{0}' does not have a strong name.
CS8003 Error Invalid signature public key specified in AssemblySignatureKeyAttribute.
CS8004 Error Type '{0}' exported from module '{1}' conflicts with type declared in primary module of this assembly.
CS8005 Error Type '{0}' exported from module '{1}' conflicts with type '{2}' exported from module '{3}'.
CS8006 Error Forwarded type '{0}' conflicts with type declared in primary module of this assembly.
CS8007 Error Type '{0}' forwarded to assembly '{1}' conflicts with type '{2}' forwarded to assembly '{3}'.
CS8008 Error Type '{0}' forwarded to assembly '{1}' conflicts with type '{2}' exported from module '{3}'.
CS8009 Warning Referenced assembly '{0}' has different culture setting of '{1}'.
CS8010 Error Agnostic assembly cannot have a processor specific module '{0}'.
CS8011 Error Assembly and module '{0}' cannot target different processors.
CS8012 Warning Referenced assembly '{0}' targets a different processor.
CS8013 Error Cryptographic failure while creating hashes.
CS8014 Error Reference to '{0}' netmodule missing.
CS8015 Error Module '{0}' is already defined in this assembly. Each module must have a unique filename.
CS8016 Error Transparent identifier member access failed for field '{0}' of '{1}'. Does the data being queried implement the query pattern?
CS8017 Error The parameter has multiple distinct default values.
CS8018 Warning Within cref attributes, nested types of generic types should be qualified.
CS8019 Hidden Unnecessary using directive.
CS8020 Hidden Unused extern alias.
CS8021 Warning No value for RuntimeMetadataVersion found. No assembly containing System.Object was found nor was a value for RuntimeMetadataVersion specified through options.
CS8022 Error Feature '{0}' is not available in C# 1. Please use language version {1} or greater.
CS8023 Error Feature '{0}' is not available in C# 2. Please use language version {1} or greater.
CS8024 Error Feature '{0}' is not available in C# 3. Please use language version {1} or greater.
CS8025 Error Feature '{0}' is not available in C# 4. Please use language version {1} or greater.
CS8026 Error Feature '{0}' is not available in C# 5. Please use language version {1} or greater.
CS8027 Error The field has multiple distinct constant values.
CS8028 Error '{0}': a class with the ComImport attribute cannot specify field initializers.
CS8029 Warning Local name '{0}' is too long for PDB. Consider shortening or compiling without /debug.
CS8030 Error Anonymous function converted to a void returning delegate cannot return a value
CS8031 Error Async lambda expression converted to a 'Task' returning delegate cannot return a value. Did you intend to return 'Task'?
CS8032 Warning An instance of analyzer {0} cannot be created from {1} : {2}.
CS8033 Warning The assembly {0} does not contain any analyzers.
CS8034 Warning Unable to load Analyzer assembly {0} : {1}
CS8035 Error Error reading ruleset file {0} - {1}
CS8036 Error Error reading debug information for '{0}'
CS8040 Info Skipping some types in analyzer assembly {0} due to a ReflectionTypeLoadException : {1}.
CS8050 Error Only auto-implemented properties can have initializers.
CS8051 Error Auto-implemented properties must have get accessors.
CS8054 Error Enums cannot contain explicit parameterless constructors
CS8055 Error Cannot emit debug information for a source text without encoding.
CS8057 Error Block bodies and expression bodies cannot both be provided.
CS8058 Error Feature '{0}' is experimental and unsupported; use '/features:{1}' to enable.
CS8059 Error Feature '{0}' is not available in C# 6. Please use language version {1} or greater.
CS8070 Error Control cannot fall out of switch from final case label ('{0}')
CS8072 Error An expression tree lambda may not contain a null propagating operator.
CS8073 Warning The result of the expression is always '{0}' since a value of type '{1}' is never equal to 'null' of type '{2}'
CS8074 Error An expression tree lambda may not contain a dictionary initializer.
CS8075 Error An extension Add method is not supported for a collection initializer in an expression lambda.
CS8076 Error Missing close delimiter '}' for interpolated expression started with '{'.
CS8077 Error A single-line comment may not be used in an interpolated string.
CS8078 Error An expression is too long or complex to compile
CS8079 Error Use of possibly unassigned auto-implemented property '{0}'
CS8080 Error Auto-implemented properties must override all accessors of the overridden property.
CS8081 Error Expression does not have a name.
CS8082 Error Sub-expression cannot be used in an argument to nameof.
CS8083 Error An alias-qualified name is not an expression.
CS8084 Error Type parameters are not allowed on a method group as an argument to 'nameof'.
CS8085 Error A 'using static' directive cannot be used to declare an alias
CS8086 Error A '{0}' character must be escaped (by doubling) in an interpolated string.
CS8087 Error A '{0}' character may only be escaped by doubling '{0}{0}' in an interpolated string.
CS8088 Error A format specifier may not contain trailing whitespace.
CS8089 Error Empty format specifier.
CS8090 Error There is an error in a referenced assembly '{0}'.
CS8091 Error '{0}' cannot be extern and have a constructor initializer
CS8092 Error Expression or declaration statement expected.
CS8093 Error Extension method groups are not allowed as an argument to 'nameof'.
CS8094 Warning Alignment value {0} has a magnitude greater than {1} and may result in a large formatted string.
CS8095 Error Length of String constant exceeds current memory limit. Try splitting the string into multiple constants.
CS8096 Error Debug entry point must be a definition of a method declared in the current compilation.
CS8097 Error #load is only allowed in scripts
CS8098 Error Cannot use #load after first token in file
CS8099 Error Source file references are not supported.
CS8100 Error The 'await' operator cannot be used in a static script variable initializer.
CS8101 Error The pathmap option was incorrectly formatted.
CS8102 Error Public signing was specified and requires a public key, but no public key was specified.
CS8103 Error Combined length of user strings used by the program exceeds allowed limit. Try to decrease use of string literals.
CS8104 Error An error occurred while writing the output file: {0}.
CS8105 Warning Attribute '{0}' is ignored when public signing is specified.
CS8106 Error Option '{0}' must be an absolute path.
CS8107 Error Feature '{0}' is not available in C# 7.0. Please use language version {1} or greater.
CS8108 Error Cannot pass argument with dynamic type to params parameter '{0}' of local function '{1}'.
CS8110 Error An expression tree may not contain a reference to a local function
CS8111 Error Invalid instrumentation kind: {0}
CS8112 Error '{0}' is a local function and must therefore always have a body.
CS8113 Error Invalid hash algorithm name: '{0}'
CS8115 Error A throw expression is not allowed in this context.
CS8116 Error It is not legal to use nullable type '{0}' in a pattern; use the underlying type '{1}' instead.
CS8117 Error Invalid operand for pattern match; value required, but found '{0}'.
CS8119 Error The switch expression must be a value; found '{0}'.
CS8120 Error The switch case has already been handled by a previous case.
CS8121 Error An expression of type '{0}' cannot be handled by a pattern of type '{1}'.
CS8122 Error An expression tree may not contain an 'is' pattern-matching operator.
CS8123 Warning The tuple element name '{0}' is ignored because a different name or no name is specified by the target type '{1}'.
CS8124 Error Tuple must contain at least two elements.
CS8125 Error Tuple element name '{0}' is only allowed at position {1}.
CS8126 Error Tuple element name '{0}' is disallowed at any position.
CS8127 Error Tuple element names must be unique.
CS8128 Error Member '{0}' was not found on type '{1}' from assembly '{2}'.
CS8129 Error No suitable 'Deconstruct' instance or extension method was found for type '{0}', with {1} out parameters and a void return type.
CS8130 Error Cannot infer the type of implicitly-typed deconstruction variable '{0}'.
CS8131 Error Deconstruct assignment requires an expression with a type on the right-hand-side.
CS8132 Error Cannot deconstruct a tuple of '{0}' elements into '{1}' variables.
CS8133 Error Cannot deconstruct dynamic objects.
CS8134 Error Deconstruction must contain at least two variables.
CS8135 Error Tuple with {0} elements cannot be converted to type '{1}'.
CS8136 Error Deconstruction 'var (...)' form disallows a specific type for 'var'.
CS8137 Error Cannot define a class or member that utilizes tuples because the compiler required type '{0}' cannot be found. Are you missing a reference?
CS8138 Error Cannot reference 'System.Runtime.CompilerServices.TupleElementNamesAttribute' explicitly. Use the tuple syntax to define tuple names.
CS8139 Error '{0}': cannot change tuple element names when overriding inherited member '{1}'
CS8140 Error '{0}' is already listed in the interface list on type '{2}' with different tuple element names, as '{1}'.
CS8141 Error The tuple element names in the signature of method '{0}' must match the tuple element names of interface method '{1}' (including on the return type).
CS8142 Error Both partial method declarations, '{0}' and '{1}', must use the same tuple element names.
CS8143 Error An expression tree may not contain a tuple literal.
CS8144 Error An expression tree may not contain a tuple conversion.
CS8145 Error Auto-implemented properties cannot return by reference
CS8146 Error Properties which return by reference must have a get accessor
CS8147 Error Properties which return by reference cannot have set accessors
CS8148 Error '{0}' must match by reference return of overridden member '{1}'
CS8149 Error By-reference returns may only be used in methods that return by reference
CS8150 Error By-value returns may only be used in methods that return by value
CS8151 Error The return expression must be of type '{0}' because this method returns by reference
CS8152 Error '{0}' does not implement interface member '{1}'. '{2}' cannot implement '{1}' because it does not have matching return by reference.
CS8153 Error An expression tree lambda may not contain a call to a method, property, or indexer that returns by reference
CS8154 Error The body of '{0}' cannot be an iterator block because '{0}' returns by reference
CS8155 Error Lambda expressions that return by reference cannot be converted to expression trees
CS8156 Error An expression cannot be used in this context because it may not be passed or returned by reference
CS8157 Error Cannot return '{0}' by reference because it was initialized to a value that cannot be returned by reference
CS8158 Error Cannot return by reference a member of '{0}' because it was initialized to a value that cannot be returned by reference
CS8159 Error Cannot return the range variable '{0}' by reference
CS8160 Error A readonly field cannot be returned by writable reference
CS8161 Error A static readonly field cannot be returned by writable reference
CS8162 Error Members of readonly field '{0}' cannot be returned by writable reference
CS8163 Error Fields of static readonly field '{0}' cannot be returned by writable reference
CS8166 Error Cannot return a parameter by reference '{0}' because it is not a ref or out parameter
CS8167 Error Cannot return by reference a member of parameter '{0}' because it is not a ref or out parameter
CS8168 Error Cannot return local '{0}' by reference because it is not a ref local
CS8169 Error Cannot return a member of local '{0}' by reference because it is not a ref local
CS8170 Error Struct members cannot return 'this' or other instance members by reference
CS8171 Error Cannot initialize a by-value variable with a reference
CS8172 Error Cannot initialize a by-reference variable with a value
CS8173 Error The expression must be of type '{0}' because it is being assigned by reference
CS8174 Error A declaration of a by-reference variable must have an initializer
CS8175 Error Cannot use ref local '{0}' inside an anonymous method, lambda expression, or query expression
CS8176 Error Iterators cannot have by-reference locals
CS8177 Error Async methods cannot have by-reference locals
CS8178 Error 'await' cannot be used in an expression containing a call to '{0}' because it returns by reference
CS8179 Error Predefined type '{0}' is not defined or imported
CS8180 Error { or ; or => expected
CS8181 Error 'new' cannot be used with tuple type. Use a tuple literal expression instead.
CS8182 Error Predefined type '{0}' must be a struct.
CS8183 Error Cannot infer the type of implicitly-typed discard.
CS8184 Error A deconstruction cannot mix declarations and expressions on the left-hand-side.
CS8185 Error A declaration is not allowed in this context.
CS8186 Error A foreach loop must declare its iteration variables.
CS8187 Error Tuple element names are not permitted on the left of a deconstruction.
CS8188 Error An expression tree may not contain a throw-expression.
CS8189 Error Ref mismatch between '{0}' and delegate '{1}'
CS8190 Error Provided source code kind is unsupported or invalid: '{0}'
CS8191 Error Provided documentation mode is unsupported or invalid: '{0}'.
CS8192 Error Provided language version is unsupported or invalid: '{0}'.
CS8196 Error Reference to an implicitly-typed out variable '{0}' is not permitted in the same argument list.
CS8197 Error Cannot infer the type of implicitly-typed out variable '{0}'.
CS8198 Error An expression tree may not contain an out argument variable declaration.
CS8199 Error The syntax 'var (...)' as an lvalue is reserved.
CS8202 Error Public signing is not supported for netmodules.
CS8203 Error Invalid assembly name: {0}
CS8204 Error For type '{0}' to be used as an AsyncMethodBuilder for type '{1}', its Task property should return type '{1}' instead of type '{2}'.
CS8205 Error Attributes are not allowed on local function parameters or type parameters
CS8206 Error Module '{0}' in assembly '{1}' is forwarding the type '{2}' to multiple assemblies: '{3}' and '{4}'.
CS8207 Error An expression tree may not contain a discard.
CS8208 Error It is not legal to use the type 'dynamic' in a pattern.
CS8209 Error A value of type 'void' may not be assigned.
CS8210 Error A tuple may not contain a value of type 'void'.
CS8300 Error Merge conflict marker encountered
CS8301 Error Invalid name for a preprocessing symbol; '{0}' is not a valid identifier
CS8302 Error Feature '{0}' is not available in C# 7.1. Please use language version {1} or greater.
CS8303 Error Specified language version '{0}' cannot have leading zeroes
CS8304 Error Compiler version: '{0}'. Language version: {1}.
CS8305 Warning '{0}' is for evaluation purposes only and is subject to change or removal in future updates.
CS8306 Error Tuple element name '{0}' is inferred. Please use language version {1} or greater to access an element by its inferred name.
CS8307 Error The first operand of an 'as' operator may not be a tuple literal without a natural type.
CS8308 Error Do not use refout when using refonly.
CS8309 Error Cannot compile net modules when using /refout or /refonly.
CS8310 Error Operator '{0}' cannot be applied to operand '{1}'
CS8311 Error Cannot use a default literal as an argument to a dynamically dispatched operation.
CS8312 Error Use of default literal is not valid in this context
CS8313 Error A default literal 'default' is not valid as a case constant. Use another literal (e.g. '0' or 'null') as appropriate. If you intended to write the default label, use 'default:' without 'case'.
CS8314 Error An expression of type '{0}' cannot be handled by a pattern of type '{1}' in C# {2}. Please use language version {3} or greater.
CS8315 Error Operator '{0}' is ambiguous on operands 'default' and 'default'
CS8320 Error Feature '{0}' is not available in C# 7.2. Please use language version {1} or greater.
CS8321 Warning The local function '{0}' is declared but never used
CS8322 Error Cannot pass argument with dynamic type to generic local function '{0}' with inferred type arguments.
CS8323 Error Named argument '{0}' is used out-of-position but is followed by an unnamed argument
CS8324 Error Named argument specifications must appear after all fixed arguments have been specified in a dynamic invocation.
CS8325 Error 'await' cannot be used in an expression containing a ref conditional operator
CS8326 Error Both conditional operator values must be ref values or neither may be a ref value
CS8327 Error The expression must be of type '{0}' to match the alternative ref value
CS8328 Error The parameter modifier '{0}' cannot be used with '{1}'
CS8329 Error Cannot use {0} '{1}' as a ref or out value because it is a readonly variable
CS8330 Error Members of {0} '{1}' cannot be used as a ref or out value because it is a readonly variable
CS8331 Error Cannot assign to {0} '{1}' because it is a readonly variable
CS8332 Error Cannot assign to a member of {0} '{1}' because it is a readonly variable
CS8333 Error Cannot return {0} '{1}' by writable reference because it is a readonly variable
CS8334 Error Members of {0} '{1}' cannot be returned by writable reference because it is a readonly variable
CS8335 Error Do not use '{0}'. This is reserved for compiler usage.
CS8336 Error The type name '{0}' is reserved to be used by the compiler.
CS8337 Error The first parameter of a 'ref' extension method '{0}' must be a value type or a generic type constrained to struct.
CS8338 Error The first parameter of the 'in' extension method '{0}' must be a concrete (non-generic) value type.
CS8340 Error Instance fields of readonly structs must be readonly.
CS8341 Error Auto-implemented instance properties in readonly structs must be readonly.
CS8342 Error Field-like events are not allowed in readonly structs.
CS8343 Error '{0}': ref structs cannot implement interfaces
CS8344 Error foreach statement cannot operate on enumerators of type '{0}' in async or iterator methods because '{0}' is a ref struct.
CS8345 Error Field or auto-implemented property cannot be of type '{0}' unless it is an instance member of a ref struct.
CS8346 Error Conversion of a stackalloc expression of type '{0}' to type '{1}' is not possible.
CS8347 Error Cannot use a result of '{0}' in this context because it may expose variables referenced by parameter '{1}' outside of their declaration scope
CS8348 Error Cannot use a member of result of '{0}' in this context because it may expose variables referenced by parameter '{1}' outside of their declaration scope
CS8349 Error Expression cannot be used in this context because it may indirectly expose variables outside of their declaration scope
CS8350 Error This combination of arguments to '{0}' is disallowed because it may expose variables referenced by parameter '{1}' outside of their declaration scope
CS8351 Error Branches of a ref conditional operator cannot refer to variables with incompatible declaration scopes
CS8352 Error Cannot use local '{0}' in this context because it may expose referenced variables outside of their declaration scope
CS8353 Error A result of a stackalloc expression of type '{0}' cannot be used in this context because it may be exposed outside of the containing method
CS8354 Error Cannot return 'this' by reference.
CS8355 Error An in parameter cannot have the Out attribute.
CS8356 Error Predefined type '{0}' is declared in multiple referenced assemblies: '{1}' and '{2}'
CS8357 Error The specified version string contains wildcards, which are not compatible with determinism. Either remove wildcards from the version string, or disable determinism for this compilation
CS8358 Error Cannot use attribute constructor '{0}' because it is has 'in' parameters.
CS8359 Warning Filter expression is a constant 'false', consider removing the catch clause
CS8360 Warning Filter expression is a constant 'false', consider removing the try-catch block
CS8361 Error A conditional expression cannot be used directly in a string interpolation because the ':' ends the interpolation. Parenthesize the conditional expression.
CS8362 Error __arglist cannot have an argument of void type
CS8364 Error Arguments with 'in' modifier cannot be used in dynamically dispatched expressions.
CS8370 Error Feature '{0}' is not available in C# 7.3. Please use language version {1} or greater.
CS8371 Warning Field-targeted attributes on auto-properties are not supported in language version {0}. Please use language version {1} or greater.
CS8372 Error Do not use 'System.Runtime.CompilerServices.FixedBuffer' attribute on a property
CS8373 Error The left-hand side of a ref assignment must be a ref local or parameter.
CS8374 Error Cannot ref-assign '{1}' to '{0}' because '{1}' has a narrower escape scope than '{0}'.
CS8375 Error The 'new()' constraint cannot be used with the 'unmanaged' constraint
CS8376 Error The 'unmanaged' constraint must come before any other constraints
CS8377 Error The type '{2}' must be a non-nullable value type, along with all fields at any level of nesting, in order to use it as parameter '{1}' in the generic type or method '{0}'
CS8378 Error __arglist cannot have an argument passed by 'in' or 'out'
CS8379 Error Type parameter '{1}' has the 'unmanaged' constraint so '{1}' cannot be used as a constraint for '{0}'
CS8380 Error '{0}': cannot specify both a constraint class and the 'unmanaged' constraint
CS8381 Error "Invalid rank specifier: expected ']'
CS8382 Error An expression tree may not contain a tuple == or != operator
CS8383 Warning The tuple element name '{0}' is ignored because a different name or no name is specified on the other side of the tuple == or != operator.
CS8384 Error Tuple types used as operands of an == or != operator must have matching cardinalities. But this operator has tuple types of cardinality {0} on the left and {1} on the right.
CS8385 Error The given expression cannot be used in a fixed statement
CS8386 Error Invalid object creation
CS8387 Warning Type parameter '{0}' has the same name as the type parameter from outer method '{1}'
CS8388 Error An out variable cannot be declared as a ref local
CS8400 Error Feature '{0}' is not available in C# 8.0. Please use language version {1} or greater.
CS8401 Error To use '@$' instead of '$@' for an interpolated verbatim string, please use language version '{0}' or greater.
CS8402 Warning 'default' is converted to 'null', not 'default({0})'
CS8403 Error Method '{0}' with an iterator block must be 'async' to return '{1}'
CS8410 Error '{0}': type used in an async using statement must be implicitly convertible to 'System.IAsyncDisposable' or implement a suitable 'DisposeAsync' method.
CS8411 Error Asynchronous foreach statement cannot operate on variables of type '{0}' because '{0}' does not contain a suitable public instance definition for '{1}'
CS8412 Error Asynchronous foreach requires that the return type '{0}' of '{1}' must have a suitable public 'MoveNextAsync' method and public 'Current' property
CS8413 Error Asynchronous foreach statement cannot operate on variables of type '{0}' because it implements multiple instantiations of '{1}'; try casting to a specific interface instantiation
CS8414 Error foreach statement cannot operate on variables of type '{0}' because '{0}' does not contain a public instance definition for '{1}'. Did you mean 'await foreach' rather than 'foreach'?
CS8415 Error Asynchronous foreach statement cannot operate on variables of type '{0}' because '{0}' does not contain a public instance definition for '{1}'. Did you mean 'foreach' rather than 'await foreach'?
CS8416 Error Cannot use a collection of dynamic type in an asynchronous foreach
CS8417 Error '{0}': type used in an async using statement must be implicitly convertible to 'System.IAsyncDisposable' or implement a suitable 'DisposeAsync' method. Did you mean 'using' rather than 'await using'?
CS8418 Error '{0}': type used in a using statement must be implicitly convertible to 'System.IDisposable' or implement a suitable 'Dispose' method. Did you mean 'await using' rather than 'using'?
CS8419 Error The body of an async-iterator method must contain a 'yield' statement.
CS8420 Error The body of an async-iterator method must contain a 'yield' statement. Consider removing 'async' from the method declaration or adding a 'yield' statement.
CS8421 Error A static local function cannot contain a reference to '{0}'.
CS8422 Error A static local function cannot contain a reference to 'this' or 'base'.
CS8423 Error Attribute '{0}' is not valid on event accessors. It is only valid on '{1}' declarations.
CS8424 Warning The EnumeratorCancellationAttribute applied to parameter '{0}' will have no effect. The attribute is only effective on a parameter of type CancellationToken in an async-iterator method returning IAsyncEnumerable
CS8425 Warning Async-iterator '{0}' has one or more parameters of type 'CancellationToken' but none of them is decorated with the 'EnumeratorCancellation' attribute, so the cancellation token parameter from the generated 'IAsyncEnumerable<>.GetAsyncEnumerator' will be unconsumed
CS8426 Error The attribute [EnumeratorCancellation] cannot be used on multiple parameters
CS8502 Error Matching the tuple type '{0}' requires '{1}' subpatterns, but '{2}' subpatterns are present.
CS8503 Error A property subpattern requires a reference to the property or field to be matched, e.g. '{{ Name: {0} }}'
CS8504 Error Pattern missing
CS8505 Error A default literal 'default' is not valid as a pattern. Use another literal (e.g. '0' or 'null') as appropriate. To match everything, use a discard pattern '_'.
CS8506 Error No best type was found for the switch expression.
CS8507 Error A single-element deconstruct pattern requires some other syntax for disambiguation. It is recommended to add a discard designator '_' after the close paren ')'.
CS8508 Error The syntax 'var' for a pattern is not permitted to refer to a type, but '{0}' is in scope here.
CS8509 Warning The switch expression does not handle all possible inputs (it is not exhaustive).
CS8510 Error The pattern has already been handled by a previous arm of the switch expression.
CS8511 Error An expression of type '{0}' cannot be handled by a pattern of type '{1}'. Please use language version '{2}' or greater to match an open type with a constant pattern.
CS8512 Warning The name '_' refers to the constant, not the discard pattern. Use 'var ' to discard the value, or '@' to refer to a constant by that name.
CS8513 Warning The name '' refers to the type '{0}', not the discard pattern. Use '@' for the type, or 'var _' to discard.
CS8514 Error An expression tree may not contain a switch expression.
CS8515 Error Parentheses are required around the switch governing expression.
CS8516 Error The name '{0}' does not identify tuple element '{1}'.
CS8517 Error The name '{0}' does not match the corresponding 'Deconstruct' parameter '{1}'.
CS8518 Error An expression of type '{0}' can never match the provided pattern.
CS8519 Warning The given expression never matches the provided pattern.
CS8520 Warning The given expression always matches the provided constant.
CS8521 Error Pattern-matching is not permitted for pointer types.
CS8522 Error Element names are not permitted when pattern-matching via 'System.Runtime.CompilerServices.ITuple'.
CS8523 Error The discard pattern is not permitted as a case label in a switch statement. Use 'case var :' for a discard pattern, or 'case @:' for a constant named '_'.
CS8597 Warning Thrown value may be null.
CS8598 Error The suppression operator is not allowed in this context
CS8600 Warning Converting null literal or possible null value to non-nullable type.
CS8601 Warning Possible null reference assignment.
CS8602 Warning Dereference of a possibly null reference.
CS8603 Warning Possible null reference return.
CS8604 Warning Possible null reference argument for parameter '{0}' in '{1}'.
CS8605 Warning Unboxing a possibly null value.
CS8606 Warning Possible null reference assignment to iteration variable
CS8607 Warning A possible null value may not be passed to a target marked with the [DisallowNull] attribute
CS8609 Warning Nullability of reference types in return type doesn't match overridden member.
CS8610 Warning Nullability of reference types in type of parameter '{0}' doesn't match overridden member.
CS8611 Warning Nullability of reference types in type of parameter '{0}' doesn't match partial method declaration.
CS8612 Warning Nullability of reference types in type doesn't match implicitly implemented member '{0}'.
CS8613 Warning Nullability of reference types in return type doesn't match implicitly implemented member '{0}'.
CS8614 Warning Nullability of reference types in type of parameter '{0}' doesn't match implicitly implemented member '{1}'.
CS8615 Warning Nullability of reference types in type doesn't match implemented member '{0}'.
CS8616 Warning Nullability of reference types in return type doesn't match implemented member '{0}'.
CS8617 Warning Nullability of reference types in type of parameter '{0}' doesn't match implemented member '{1}'.
CS8618 Warning Non-nullable {0} '{1}' is uninitialized.
CS8619 Warning Nullability of reference types in value of type '{0}' doesn't match target type '{1}'.
CS8620 Warning Argument of type '{0}' cannot be used for parameter '{2}' of type '{1}' in '{3}' due to differences in the nullability of reference types.
CS8621 Warning Nullability of reference types in return type of '{0}' doesn't match the target delegate '{1}'.
CS8622 Warning Nullability of reference types in type of parameter '{0}' of '{1}' doesn't match the target delegate '{2}'.
CS8623 Error Explicit application of 'System.Runtime.CompilerServices.NullableAttribute' is not allowed.
CS8624 Warning Argument of type '{0}' cannot be used as an output of type '{1}' for parameter '{2}' in '{3}' due to differences in the nullability of reference types.
CS8625 Warning Cannot convert null literal to non-nullable reference type.
CS8626 Warning The 'as' operator may produce a null value when '{0}' is a non-nullable reference type.
CS8627 Error A nullable type parameter must be known to be a value type or non-nullable reference type. Consider adding a 'class', 'struct', or type constraint.
CS8628 Error Cannot use a nullable reference type in object creation.
CS8629 Warning Nullable value type may be null.
CS8630 Error Invalid '{0}' value: '{1}' for C# {2}. Please use language version '{3}' or greater.
CS8631 Warning The type '{3}' cannot be used as type parameter '{2}' in the generic type or method '{0}'. Nullability of type argument '{3}' doesn't match constraint type '{1}'.
CS8632 Warning The annotation for nullable reference types should only be used in code within a '#nullable' context.
CS8633 Warning Nullability in constraints for type parameter '{0}' of method '{1}' doesn't match the constraints for type parameter '{2}' of interface method '{3}'. Consider using an explicit interface implementation instead.
CS8634 Warning The type '{2}' cannot be used as type parameter '{1}' in the generic type or method '{0}'. Nullability of type argument '{2}' doesn't match 'class' constraint.
CS8635 Error Unexpected character sequence '...'
CS8636 Error Invalid option '{0}' for /nullable; must be 'disable', 'enable' or 'warnings'
CS8637 Error Expected 'enable', 'disable', or 'restore'
CS8638 Warning Conditional access may produce a null value when '{0}' is a non-nullable reference type.
CS8639 Error The typeof operator cannot be used on a nullable reference type
CS8640 Error Expression tree cannot contain value of ref struct or restricted type '{0}'.
CS8641 Error 'else' cannot start a statement.
CS8642 Error An expression tree may not contain a null coalescing assignment
CS8643 Warning Nullability of reference types in explicit interface specifier doesn't match interface implemented by the type.
CS8644 Warning '{0}' does not implement interface member '{1}'. Nullability of reference types in interface implemented by the base type doesn't match.
CS8645 Warning '{0}' is already listed in the interface list on type '{1}' with different nullability of reference types.
CS8646 Error '{0}' is explicitly implemented more than once.
CS8647 Error A using variable cannot be used directly within a switch section (consider using braces).
CS8648 Error A goto cannot jump to a location after a using declaration.
CS8649 Error A goto cannot jump to a location before a using declaration within the same block.
CS8650 Error It is not legal to use nullable reference type '{0}?' in an is-type expression; use the underlying type '{0}' instead.
CS8651 Error It is not legal to use nullable reference type '{0}?' in an as expression; use the underlying type '{0}' instead.
CS8652 Error The feature '{0}' is currently in Preview and unsupported. To use Preview features, use the 'preview' language version.
CS8653 Warning A default expression introduces a null value when '{0}' is a non-nullable reference type.
CS8654 Warning A null literal introduces a null value when '{0}' is a non-nullable reference type.
CS8655 Warning The switch expression does not handle some null inputs (it is not exhaustive).
CS8656 Warning Call to non-readonly member '{0}' from a 'readonly' member results in an implicit copy of '{1}'.
CS8657 Error Static member '{0}' cannot be marked 'readonly'.
CS8658 Error Auto-implemented 'set' accessor '{0}' cannot be marked 'readonly'.
CS8659 Error Auto-implemented property '{0}' cannot be marked 'readonly' because it has a 'set' accessor.
CS8660 Error Cannot specify 'readonly' modifiers on both property or indexer '{0}' and its accessor. Remove one of them.
CS8661 Error Cannot specify 'readonly' modifiers on both accessors of property or indexer '{0}'. Instead, put a 'readonly' modifier on the property itself.
CS8662 Error Field-like event '{0}' cannot be 'readonly'.
CS8663 Error Both partial method declarations must be readonly or neither may be readonly
CS8664 Error '{0}': 'readonly' can only be used on accessors if the property or indexer has both a get and a set accessor
CS8665 Error Method '{0}' specifies a 'class' constraint for type parameter '{1}', but corresponding type parameter '{2}' of overridden or explicitly implemented method '{3}' is not a reference type.
CS8666 Error Method '{0}' specifies a 'struct' constraint for type parameter '{1}', but corresponding type parameter '{2}' of overridden or explicitly implemented method '{3}' is not a non-nullable value type.
CS8667 Warning Partial method declarations of '{0}' have inconsistent nullability in constraints for type parameter '{1}'
CS8700 Error Multiple analyzer config files cannot be in the same directory ('{0}').
CS8701 Error Target runtime doesn't support default interface implementation.
CS8702 Error '{0}' cannot implement interface member '{1}' in type '{2}' because the target runtime doesn't support default interface implementation.
CS8703 Error The modifier '{0}' is not valid for this item in C# {1}. Please use language version '{2}' or greater.
CS8704 Error '{0}' does not implement interface member '{1}'. '{2}' cannot implicitly implement a non-public member.
CS8705 Error Interface member '{0}' does not have a most specific implementation. Neither '{1}', nor '{2}' are most specific.
CS8706 Error '{0}' cannot implement interface member '{1}' in type '{2}' because feature '{3}' is not available in C# {4}. Please use language version '{5}' or greater.
CS8707 Error Target runtime doesn't support 'protected', 'protected internal', or 'private protected' accessibility for a member of an interface.
CS8711 Error Type '{0}' cannot be embedded because it has a non-abstract member. Consider setting the 'Embed Interop Types' property to false.
CS8712 Error '{0}': abstract event cannot use event accessor syntax
CS8713 Error The 'notnull' constraint must come before any other constraints
CS8714 Warning The type '{2}' cannot be used as type parameter '{1}' in the generic type or method '{0}'. Nullability of type argument '{2}' doesn't match 'notnull' constraint.

Statistics

Severity Count
Fatal 7
Error 1177
Warning 223
Info 1
Hidden 2
Total 1412
@Z-Farook
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Z-Farook commented Jul 27, 2020

what do when you get CS8507 error?

@thomaslevesque
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@Z-Farook, sorry, no idea...

@mehsan1995
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Receiving error "CS8103 Combined length of user strings used by the program exceeds allowed limit. Try to decrease use of string literals." any one can help?

@thomaslevesque
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thomaslevesque commented Jun 10, 2021

@mehsan851 this isn't a Q&A forum, it's just a list of all possible C# compiler errors. If you need help, I suggest you use Stack Overflow instead.

@TehEpikNoobKing
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how do i fix
'{0}' explicit method implementation cannot implement '{1}' because it is an accessor
or
CS0683

@thomaslevesque
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@TehEpikNoobKing no idea, especially without seeing your code 😉
As mentioned above, this isn't the place to ask questions on how to solve C# compiler errors, it's just a list of them. I suggest you ask on Stack Overflow instead.

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