DIAGNOSTICS.md

Compiler diagnostics

List of diagnostics that the compiler can produce. In the future, we will add a description of each diagnosis with examples here. This description will be used to generate documentation and the --explain flag.

Lexer

• E0001: Unexpected input character

• E0002: Not closed string literal

• E0003: Not closed block comment

• E0004: Not closed rune literal

• E0005: Usage of a reserved identifier

• E0006: Invalid digit in literal

• E0007: Literal has no digits

• E0008: Invalid digit separator

• E0009: Invalid radix point

• E0010: Wrong mantissa for exponent

• E0011: Illegal character NUL

• E0012: Illegal byte order mark

• E0013: Unknown string prefix

• E0014: Rune literal cannot be empty

• E0015: Rune literal cannot contain new line in source code

• E0016: Rune literal cannot contain more than one character

• E0017: Unknown escape sequence

• E0018: Escape sequence is not terminated

• E0019: Illegal character in escape sequence TODO: Check IDs must then be re-numbered

• E0019.1: Escape sequence is invalid Unicode code point

• E0019.2: Escape sequence is invalid octal number

• E0019.3: Unknown rune literal prefix

• E0019.4: Byte literal cannot contains non-ASCII character

• E0019.5: Escape sequence is invalid byte value

• E0019.6: Byte literal cannot contain escape sequence with Unicode code point

• E0019.7: String literal cannot contain \0 character

• E0019.9: Not terminated string interpolation

• E0019.10: No need to escape $ in C string literal

Parser

• E0020: Not expected token
• E0021: Missing condition in if expression
• E0022: Method receiver must have a name
• E0023: Method receiver must have a type
• E0024: Multiline comments cannot be used in array literal
• E0025: Result type should have one or two types in ![]
• E0026: Prefix ++/-- is not supported
• E0027: No need to specify : in type declaration
• E0028: Parameter should have a name
• E0029: Invalid comparison operator (=== and !== are not supported)
• E0030: Too many expressions for fixed array size
• E0031: Import alias cannot be qualified
• E0032: To declare multiple constants use const ( ... ) syntax
• E0033: Constant definition cannot have a type annotation
• E0034: Return types are denoted using ->
• E0035: ...foo update syntax is allowed only as first expression
• E0036: Use $if/$else instead of if/else in compile time if
• E0037: Cannot use a := foo() in comptime if condition
• E0038: To declare multiple vars use var ( ... ) syntax
• E0039: Missed [ after # in attribute
• E0040: Match expression can have only one else branch
• E0041: Multiply return types must be wrapped in parentheses
• E0042: Function literals cannot have a name
• E0043: Module var definition cannot have a type annotation

Type checker

• E0050: Type mismatch
• E0051: Cannot dereference a non-pointer type
• E0052: Type incorrectly implements interface
• E0053: Cannot index a non-array type
• E0054: nil can be cast only to a pointer type
• E0055: Generic type parameters count mismatch
• E0056: Cannot pass a type as generic argument due constraint
• E0057: Missed constraint for generic type parameter
• E0058: Cannot instantiate a non-generic type
• E0059: Generic argument in the method receiver must have the same name as the generic parameter in the declaration
• E0060: Cannot use an Option type without unwrapping
• E0061: No need to check a pointer type for nil because it cannot be nil by design (warning)
• E0062: is condition is always true at this point (warning)
• E0063: is condition is always false at this point (warning)
• E0064: Pointer dereference requires unsafe block
• E0065: Pointer arithmetic requires unsafe block
• E0066: Pointer indexing requires unsafe block
• E0067: or can only be used with Option or Result types
• E0068: Cannot unwrap a non-Option and non-Result type
• E0069: Cannot call expression of type name

Checker

• E0070: Redeclaration of name
• E0071: Shadowing of name
• E0072: Variadic parameter must be the last parameter in the signature
• E0073: Duplicate parameter name name
• E0074: Wrong number of arguments
• E0075: Return statement with expression in function with no return type
• E0076: Return statement missing expression
• E0077: Unknown field
• E0078: Unknown method
• E0079: Unresolved identifier
• E0080: Cannot match on bare none, cast it to a concrete Option type first
• E0081: Receiver type cannot be variadic
• E0082: Literal cast overflow
• E0083: C bindings should always use pointers instead references
• E0084: Unknown interface method
• E0085: Overflow while execute compile-time expression
• E0086: Unreachable code (warning)
• E0087: Not all code paths return a value
• E0088: Assigned value is not used (warning)
• E0089: Previous assigned value is not used (warning)
• E0090: Unused variable (warning)
• E0091: Break statements must be inside a loop
• E0092: Continue statements must be inside a loop
• E0093: Nested Option types are not allowed
• E0094: Function result type cannot be void
• E0095: Function without result cannot be used as a value
• E0096: Function that never returns cannot be used as a value
• E0097: Cannot use return in function that never returns
• E0098: Unknown enum variant
• E0099: Enum with no variants
• E0100: Cannot check if a non-pointer type is nil/not-nil
• E0101: Nested unsafe block is not allowed
• E0102: Cannot iterate over a non-iterable type
• E0103: Cannot determine a type of enum to fetch
• E0104: main function cannot have parameters
• E0105: main function cannot have a return type, to return a value use os.exit()
• E0106: none can be cast only to an Option type
• E0107: Option propagation can only be used with Option types
• E0108: Option propagation can only be used in function that returns an Option type
• E0109: Cannot infer a type of array
• E0110: T{} initialization is only allowed for structs, aliases for structs, arrays, maps, and channels
• E0111: Included file not found by C compiler
• E0112: Access to .data of string literal can be replaced with C string (warning)
• E0113: Complex boolean expression should use parentheses
• E0114: Unused import (warning)
• E0115: Shadowing of import name
• E0116: Go-style cast is not supported
• E0117: C binding arguments count mismatch
• E0118: Deferred expression must be a function call
• E0119: Duplicate field name name
• E0120: Cannot cast rune literal to u8, use b prefix to create a byte literal
• E0121: Comparison of unsigned integers with zero is always true or false (warning)
• E0122: Cannot cast a pointer to a reference type
• E0123: Cannot cast &void outside unsafe block
• E0124: Not enough information to infer a type of lambda parameter
• E0125: Unnecessary parentheses for if condition (warning)
• E0126: if expression must have else branch
• E0127: Division or modulo by zero
• E0128: Cannot infer a type of generic parameter in call
• E0129: Cannot increment or decrement expression of type
• E0130: C binding functions cannot have a body
• E0131: Cannot infer a type of generic parameter in type instantiation
• E0132: Unsupported compile-time condition
• E0133: Cannot use a type in string interpolation because it does not have str method
• E0134: Cannot find module name to import
• E0135: Cannot access private element name from module name
• E0136: Cannot have a second variable in for loop over range
• E0137: Cannot cast a type to interface name because it does not implement it
• E0138: Unpacking expression must be the last argument in the call
• E0139: Only arrays can be unpacked
• E0140: Unpacking in array initializer is not allowed
• E0141: is check is always false or true because a type not implements interface
• E0142: Right operand of is operator must be a struct, interface, union or type alias
• E0143: Implicit err variable can be used only when or block used for Result
• E0144: Cannot take mutable reference to immutable variable
• E0145: Cannot assign to immutable variable
• E0146: Cannot break/continue to label since label is not directly attached to any enclosing loop
• E0147: ! operator can be used only with bool type
• E0148: || and && operators can be used only with bool type
• E0149: Cannot cast an immutable pointer to mutable one
• E0150: When or is used as an expression, it must have expression in the block
• E0151: Cannot unpack expression as i-th argument in function
• E0152: Spawn expression must be a function call
• E0153: Forbidden cast
• E0154: Integer literal too big to fit in i32 type
• E0155: if expression body must end with expression, return statement or break/continue
• E0156: Empty match expression (warning)
• E0157: match expression with only else branch is not allowed
• E0158: match expression with type arms can only be used with interface or union types
• E0159: match arm expressions cannot have both types and values in the same arm
• E0160: Cannot match type name because it is not implemented interface from match expression
• E0161: match expression for enums must be exhaustive
• E0162: match expression already matches all variants of enum E, so else branch is never executed
• E0163: Unnecessary parentheses for match expression (warning)
• E0164: Expression matched several times in match expression
• E0165: match expression body must end with expression, return statement or break/continue
• E0166: if condition must have bool
• E0167: Cannot break/continue to label since label is outside current function literal
• E0168: Unnecessary parentheses for for statement (warning)
• E0169: Cannot increment or decrement immutable variable
• E0170: Assignment count mismatch
• E0171: Cannot unpack non-tuple type
• E0172: Tuple type does not have any fields or methods
• E0173: Wrong variable name in declaration
• E0174: Cannot call static interface method
• E0175: Cannot assign bare none to variable, cast it to a concrete Option type first
• E0176: Cannot assign to expr because it is not a lvalue
• E0177: Cannot declare variable _, this name is reserved for placeholders
• E0178: Cannot assign bare nil to variable, cast it to a concrete pointer type first
• E0179: Placeholder _ cannot be mutable
• E0180: Wrong usage of placeholder
• E0181: Cannot inc/dec non-lvalue expression
• E0182: Placeholder _ is not needed here (warning)
• E0183: Placeholder _ is invalid here
• E0184: Unpacking expression is only allowed in function call or type initializer
• E0185: Cannot access to fields for interfaces
• E0186: .str() can be omitted in string interpolation because it is called implicitly (warning)
• E0187: Variable in range expression cannot be mutable
• E0188: Cannot get tuple element with index i because tuple has only n elements
• E0189: Index of tuple must be a constant integer
• E0190: Test name must be string literal
• E0191: Test declaration cannot have a signature
• E0192: Array initializer must have zero or one parameter
• E0193: Array initializer must be a lambda expression
• E0194: Array initializer parameter must have usize type
• E0195: Cannot receive from a non-Channel type
• E0196: Cannot receive from a non-Channel type
• E0197: Only cap field can be specified for a Channel type
• E0198: Only len, cap and init fields can be specified for an Array type
• E0199: Only cap field can be specified for a Map type
• E0200: Duplicate embedded interface
• E0201: Embedded type in interfaces must be identifier, selector expression, or generic version of them
• E0202: Only interfaces can be embedded in interface
• E0203: Embedded interface X causes conflict for method Y
• E0204: Result propagation can only be used with Result types
• E0205: Result propagation can only be used in function that returns a Result type
• E0206: Enum variant out of range for a backed type
• E0207: Enum backed type must be one of u8, u16, u32, u64, i8, i16, i32, i64
• E0208: Array index must be of type usize
• E0209: Only init and no_init fields can be specified for a fixed array type
• E0210: Unused return value of function name that must be used
• E0211: Cannot evaluate constant expression
• E0212: Duplicate enum value
• E0213: Union type should have at least two types
• E0214: Cannot call static method via instance
• E0215: Cannot call instance method as static
• E0216: Operator is not defined for a type
• E0217: Cannot cast expression to Union because it's not one of its types
• E0218: Right operand of is operator is not a member of the union type
• E0219: Import names must have at least one name
• E0220: Assert condition must have bool type
• E0221: Assert message must have string type
• E0222: Function has no parameter with such a name
• E0223: Positional argument after named argument is not allowed
• E0224: Duplicate named argument
• E0225: Cannot access field of a pointer outside unsafe block
• E0226: mut expression can be used only in variable declaration
• E0227: Inclusive range ..= always panic in runtime due out of range
• E0228: offset_of argument must be a string literal
• E0229: Cannot get offset of non-struct type field
• E0230: Cannot get field offset of unknown field
• E0231: Cannot access field of C-style union struct outside unsafe block
• E0232: Cannot initialize more than one field of C-style union struct
• E0233: Cannot clone C-style union struct
• E0234: Clone expression does not have any effect, because all fields are already initialized
• E0235: Explicit Option propagation can be safely removed in return expressions (warning)
• E0236: or { return none } can be safely removed in return expressions (warning)
• E0237: Explicit Result propagation can be safely removed in return expressions (warning)
• E0238: Cannot use safe access on a non-Option type
• E0239: Cannot unpack Option/Result tuple, you need to unwrap an Option/Result type first
• E0240: match expression for unions must be exhaustive
• E0241: match expression already matches all members of union U, so else branch is never executed
• E0242: Cannot cast a union type to another type because it's not one of its types
• E0243: Cannot access enum variant via expression
• E0244: Cannot match type name because it is not member of a union type
• E0245: Add #[typedef] attribute to C struct
• E0246: Cannot cast an immutable reference to mutable one
• E0247: Match expression must have else branch
• E0248: Enum variant value must have one of the following types:
• E0249: Cast is always successful, use as instead of as?
• E0250: Select expression with single timeout arm is not allowed
• E0251: Invalid expression in select arm
• E0252: Select expression with only timeout and else arm is not allowed, add at least one non timeout/else arm
• E0253: Invalid statement in select arm, expected send, assign, var declaration or expression statement
• E0254: Statement in select handled more than once
• E0255: Select expression with only else arm is not allowed, add at least one non timeout/else arm
• E0256: Reaching unwrap() call will always panic
• E0257: Checking expression for none is always true/false
• E0258: Cannot use ?. to access module members
• E0259: Cannot create instance of generic type T without reflection.Struct constraint
• E0260: Compiler error function call is reached
• E0261: Compiler warning function call is reached (warning)
• E0262: compiler_error and compiler_warning functions must have a string literal argument
• E0263: Generic argument name in the method receiver must be an identifier
• E0264: Cannot shift value of type T by X bits, maximum shift value is Y
• E0265: Result of compile time constant folding overflows the maximum value of type T
• E0266: Cannot shift value of type T by X bits, shift count is negative
• E0267: Enum variant value overflow for type T
• E0268: Cannot iterate with mutation over immutable string
• E0269: Cannot iterate with mutation over a channel
• E0270: Left and right operands of is operator are the same type, so this check is always true (warning)
• E0271: Test files should be defined with main module name for now
• E0272: Cannot slice a non-array and non-string type
• E0273: Result type returned from function must be used