Error Code Reference
YaoXiang compiler uses error codes to identify different types of diagnostic information. Error codes are grouped by number range, with each error code corresponding to a specific error scenario.
E0xxx -- Lexical and Syntax Analysis
Errors produced during the Lexer and Parser phases.
| Error Code | Template | Description |
|---|---|---|
| E0001 | Invalid character: '{char}' | Invalid character |
| E0002 | Invalid number literal: '{literal}' | Invalid number literal |
| E0003 | Unterminated string starting at line {line} | Unterminated string |
| E0004 | Invalid character literal: '{literal}' | Invalid character literal |
| E0010 | Expected {expected}, found {found} | Expected token |
| E0011 | Unexpected token: '{token}' | Unexpected token |
| E0012 | Invalid syntax: {reason} | Invalid syntax |
| E0013 | Mismatched {bracket_type}: opened at line {open_line}, column {open_col}, not closed | Mismatched bracket |
| E0014 | Missing semicolon after {statement} | Missing semicolon |
E1xxx -- Type Checking
Errors produced during the type checking phase, covering variable types, function calls, pattern matching, generic instantiation, concurrency semantics, and error propagation.
| Error Code | Template | Description |
|---|---|---|
| E1001 | Unknown variable: '{name}' | Unknown variable |
| E1002 | Expected type '{expected}', found type '{found}' | Type mismatch |
| E1003 | Unknown type: '{type}' | Unknown type |
| E1010 | Function '{func}' expects {expected} arguments, found {found} | Argument count mismatch |
| E1011 | Parameter type mismatch: expected '{expected}', found '{found}' | Parameter type mismatch |
| E1012 | Return type mismatch: expected '{expected}', found '{found}' | Return type mismatch |
| E1013 | Function not found: '{func}' | Function not found |
| E1020 | Cannot infer type for '{expr}' | Cannot infer type |
| E1021 | Type inference conflict: {reason} | Type inference conflict |
| E1030 | Pattern non-exhaustive: missing patterns {patterns} | Pattern non-exhaustive |
| E1031 | Unreachable pattern: '{pattern}' | Unreachable pattern |
| E1040 | Operation '{op}' is not supported for type '{type}' | Operation not supported |
| E1041 | Index out of bounds: valid range is 0..{max}, found {index} | Index out of bounds |
| E1042 | Field '{field}' not found in struct '{struct}' | Field not found |
| E1050 | Logical operation requires boolean operands, found '{left}' and '{right}' | Boolean operand required |
| E1051 | Logical NOT requires boolean operand, found '{type}' | Logical NOT requires boolean operand |
| E1052 | Cannot dereference type '{type}', expected pointer type | Invalid dereference |
| E1053 | Cannot access field on non-struct type '{type}' | Non-struct field access |
| E1054 | Condition must be boolean, found '{type}' | Condition type mismatch |
| E1055 | Constraint type '{type}' can only be used in generic context | Constraint in non-generic context |
| E1060 | Expected {expected} type argument(s), found {found} | Type argument count mismatch |
| E1061 | Cannot instantiate generic type with given arguments | Cannot instantiate generic |
| E1081 | `?` is only allowed inside functions returning Result | ? is only allowed inside functions returning Result |
| E1082 | `?` requires a Result expression, found '{type}' | ? requires a Result expression |
| E1083 | Result error type mismatch for `?`: expected '{expected}', found '{found}' | ? error type mismatch |
| E1090 | Type: Type = Type | Unspeakable (Easter egg) |
| E1091 | Generic meta-type self-reference is not allowed: '{decl}' | Invalid generic meta-type |
| E1062 | Const generic constraint violation: {reason} | const generic constraint violation |
| E1064 | Invalid binding position(s) {positions} for function with {total} parameter(s) | Invalid binding position index (RFC-004) |
| E1095 | Unknown interface: '{name}' | Unknown interface (RFC-011a) |
| E1096 | Interface '{name}' expects {expected} type argument(s), found {found} | Interface instantiation argument count mismatch |
| E1097 | Interface member '{member}' conflicts with field of type '{type}' | Interface member conflicts with field name |
| E1098 | Type '{type}' does not implement '{interface}.{method}' | Interface method not implemented |
| E1099 | Signature mismatch for '{type}.{method}': expected '{expected}', found '{found}' | Interface method signature mismatch |
| E1100 | Duplicate implementation of '{type}.{method}' (override is not allowed) | Duplicate method implementation (override forbidden) |
| E1101 | Type '{type}' does not implement interface '{interface}' and cannot enter this existential position | Type does not implement interface (existential type member check) |
E2xxx -- Semantic Analysis
Errors produced during the semantic analysis phase, covering scope, variable lifetime, ownership, and function signature resolution.
| Error Code | Template | Description |
|---|---|---|
| E2001 | Variable '{name}' is not in scope | Scope error |
| E2002 | Duplicate definition: '{name}' is already defined in this scope | Duplicate definition |
| E2003 | Ownership constraint violated: {reason} | Ownership error |
| E2010 | Cannot assign to immutable variable '{name}' | Immutable assignment |
| E2011 | Use of uninitialized variable '{name}' | Use of uninitialized variable |
| E2012 | Mutability conflict: cannot use mutable reference in immutable context | Mutability conflict |
| E2013 | Cannot shadow existing variable '{name}' | Variable shadowing |
| E2014 | '{name}' has been moved and cannot be used | Use of moved variable |
| E2090 | Invalid signature: {reason} | Invalid signature |
| E2091 | Invalid signature: unknown type '{type_name}' | Signature unknown type |
| E2092 | Invalid signature: missing '->' | Signature missing arrow |
| E2093 | Invalid signature: duplicate parameter '{name}' | Duplicate parameter name |
| E2094 | Invalid signature: generic '{name}' shadows outer generic | Generic parameter shadowing |
| E2095 | Invalid signature: parameter '{name}' shadows generic | Parameter name shadows generic |
E4xxx -- Generics and Traits
Errors related to generic constraints and the trait system.
| Error Code | Template | Description |
|---|---|---|
| E4001 | Type '{type}' does not satisfy the trait bound '{trait}' | Generic constraint violation |
| E4002 | Trait '{trait}' not found | Trait not found |
| E4003 | Missing implementation for trait '{trait}' for type '{type}' | Missing trait implementation |
| E4004 | Conflicting trait implementations for '{trait}' | Conflicting trait implementations |
| E4005 | Associated type '{assoc_type}' not found in '{container}' | Associated type not found |
E5xxx -- Modules and Imports
Errors related to the module system and imports.
| Error Code | Template | Description |
|---|---|---|
| E5001 | Module '{module}' not found | Module not found |
| E5002 | Failed to import module '{module}': {reason} | Import error |
| E5003 | Export '{export}' not found in module '{module}' | Export not found |
| E5004 | Circular dependency detected: {path} | Circular dependency |
| E5005 | Invalid module path: '{path}' | Invalid module path |
| E5006 | Duplicate import: '{name}' is already imported | Duplicate import |
| E5007 | Module '{module}' exports: {available} | Module export hint |
E6xxx -- Runtime
Errors produced during the runtime phase.
| Error Code | Template | Description |
|---|---|---|
| E6001 | Division by zero in expression: {expr} | Division by zero |
| E6003 | Array index out of bounds: valid range is 0..{max}, found {index} | Array index out of bounds |
| E6004 | Stack overflow: recursion depth exceeded limit {limit} | Stack overflow |
| E6005 | Assertion failed: {condition} | Assertion failed |
| E6006 | Function not found: '{func}' | Function not found (runtime) |
| E6007 | Runtime error: {message} | Runtime error |
E7xxx -- I/O and System
I/O operations and system-level errors.
| Error Code | Template | Description |
|---|---|---|
| E7001 | File not found: '{path}' | File not found |
| E7002 | Permission denied: '{path}' | Permission denied |
| E7003 | I/O error: {reason} | I/O error |
| E7004 | Network error: {reason} | Network error |
E8xxx -- Internal Compiler Errors
Internal compiler errors, typically indicating a bug in the compiler itself. If you encounter such errors, please report them at GitHub Issues.
| Error Code | Template | Description |
|---|---|---|
| E8001 | Internal compiler error: {message} | Internal compiler error |
| E8002 | Unexpected compiler panic: {reason} | Unexpected panic |
| E8003 | Compiler phase error: {phase} - {message} | Compiler phase error |
W1xxx -- Warnings
Warnings related to dead code detection. Warnings do not prevent compilation but indicate potential issues in the code.
| Error Code | Template | Description |
|---|---|---|
| W1001 | Unused exported function: '{name}' | Unused exported function |
| W1002 | Unused exported type: '{name}' | Unused exported type |
| W1003 | Unused import: '{name}' | Unused import |
| W1004 | Unused exported variable: '{name}' | Unused exported variable |
| W1005 | Unused exported method: '{name}' | Unused exported method |
| W1063 | const generic constraint cannot be evaluated: `{constraint}` ({var} = {value}) | const generic constraint cannot be evaluated |
| W1080 | Constraint cannot be proven at compile-time, degraded to runtime check | Compile-time proof degradation |
A total of 118 diagnostic codes (111 error codes + 7 warning codes), with the define_codes! registry (src/util/diagnostic/codes/) as the authoritative source; the complete registration list for each code follows the registry, and this page lists common codes by family.