Error Codes

cnegc diagnostics use stable error codes so errors can be documented and referenced consistently. All diagnostics show source path, line, and column.

Parse errors (E1xxx)

Code	Description
E1001	Expected token missing in current grammar position
E1002	Unexpected token for current grammar rule
E1003	Invalid type syntax
E1004	Invalid character during lexing
E1005	Unterminated string literal
E1006	Invalid assignment target in statement syntax
E1007	result type prefix is missing its inner type
E1008	ptr or slice type prefix is missing its inner type

Semantic errors (E3xxx)

Code	Description
E3001	Duplicate function name
E3002	Unknown name
E3003	Duplicate local binding in the same scope
E3004	Type mismatch
E3005	Control-flow condition is not bool
E3006	Assignment to immutable binding
E3007	Non-void function does not return on every path
E3008	Incorrect function call arity
E3009	Unknown or invalid field access
E3010	Invalid indexing target
E3011	Array literal size mismatch
E3012	Unknown declared type or module-qualified type without matching import
E3013	Duplicate struct name
E3014	Invalid call target or module-as-value usage
E3015	err used without an expected result type
E3016	Duplicate import alias
E3017	Module file could not be resolved or loaded
E3018	Cyclic module import
E3019	free requires a pointer or string value
E3020	Internal typed IR lowering invariant failed
E3021	LLVM backend does not support the requested feature yet
E3022	External backend toolchain step failed
E3023	Public API exposes a private type
E3024	result.value used without a proven-ok check
E3025	Module-level constant initializer uses a runtime-only operation
E3026	Cyclic module-level constant definition
E3027	Duplicate or conflicting top-level constant name
E3028	Integer literal is out of range for the target type
E3029	if expression branch does not produce a value
E3030	if expression branch types do not match
E3031	addr target is not addressable
E3032	deref requires a pointer value
E3033	try used outside a result ... function
E3034	try initializer is not a result ... value
E3035	addr cannot target an immutable binding
E3036	addr cannot target a module constant
E3037	free cannot release a slice value
E3038	free cannot release a result wrapper directly
E3039	Array size must be a non-negative integer constant
E3040	Array repeat count must be a non-negative integer constant
E3041	zalloc requires an enclosing zone block
E3042	Zone-owned value cannot escape through return
E3043	free cannot release zone-owned memory
E3044	Zone-owned value cannot escape into outer storage
E3045	Zone-owned value cannot cross a function call boundary yet

Runtime memory errors (R4xxx)

Code	Description
R4001	Allocation failed
R4002	realloc used on an unmanaged pointer
R4003	free used on an unmanaged pointer
R4004	Memory leak summary reported at shutdown
R4005	Leaked allocation detail reported at shutdown
R4006	Allocation size overflow
R4008	realloc failed and preserved the original pointer
R4009	realloc size overflow
R4010	Double free detected
R4011	free used on an interior pointer instead of the allocation start
R4013	Use-after-free detected within the quarantine window
R4016	Buffer overflow detected by allocator guard checks
R4017	Buffer underflow detected by allocator guard checks

Diagnostic style

• Show source path, line, and column.
• One clear primary sentence per diagnostic.
• Prefer describing both expected and actual types for mismatches.
• Reject ambiguous truthiness in conditions with E3005.
• Report missing struct fields directly at the literal or access site.
• Recover after common syntax mistakes when possible so multiple real errors can be reported in one pass.