Diagnostic index

Every diagnostic code the compiler can emit, with a one-line summary of the cause, grouped by category. For step-by-step cause-and-fix guidance on the most common ones, see the troubleshooting guides.

There are 327 codes in total.

Agents

Code	Summary	Construct
bynk.agent.construction_arity	An agent was constructed with the wrong number of key arguments.	agent_decl
bynk.agent.handler_arity	An agent handler was called with the wrong number of arguments.	agent_decl
bynk.agent.handler_not_found	Called a handler the agent does not declare.	agent_decl
bynk.agent.key_mismatch	An agent key argument has the wrong type.	agent_decl
bynk.agent.outside_context	An agent was declared outside a context.	agent_decl
bynk.agent.return_not_effect	An agent handler’s return type is not an Effect.	agent_decl
bynk.agents.bad_state_initialiser	An agent store field initialiser is not a static value of the field’s type.	store_field
bynk.agents.non_zeroable_state_field	An agent store field has no initialiser and no implicit zero value.	store_field

Assertions

Code	Summary	Construct
bynk.assert.non_bool	assert was given a non-Bool expression.	assert_expr
bynk.assert.outside_test	assert was used outside a test case body.	assert_expr

Boundaries

Code	Summary	Construct
bynk.boundary.structural_mismatch	Data crossing a context boundary did not match the expected shape.

Capabilities

Code	Summary	Construct
bynk.capability.op_arity	A capability operation was called with the wrong number of arguments.	capability_decl
bynk.capability.outside_context	A capability was declared outside a context.	capability_decl
bynk.capability.unknown_operation	Referenced an operation the capability does not declare.	capability_decl

Consumes

Code	Summary	Construct
bynk.consumes.alias_conflict	Two consumes aliases collide.	consumes_decl
bynk.consumes.capability_name_clash	Two flattened consumes U { Cap } capabilities collide, or one clashes with a local capability.	consumes_decl
bynk.consumes.in_commons	consumes appears in a commons (it is only valid in a context).	consumes_decl
bynk.consumes.name_conflict	A consumes name collides with another name in scope.	consumes_decl
bynk.consumes.self_reference	A context consumes itself.	consumes_decl
bynk.consumes.service_arity	A consumed service was called with the wrong number of arguments.	consumes_decl
bynk.consumes.target_is_commons	consumes targets a commons instead of a context.	consumes_decl
bynk.consumes.unknown_context	consumes names a context that does not exist.	consumes_decl
bynk.consumes.unknown_service	Called a service the consumed context does not declare.	consumes_decl

Contexts

Code	Summary	Construct
bynk.context.consumes_cycle	Contexts form a consumes dependency cycle.
bynk.context.external_construction	A context-owned type was constructed from outside that context.
bynk.context.external_provider	A bodiless (external) provider was declared outside an adapter.	provider_decl
bynk.context.opaque_inspection	An opaquely-exported type was inspected from outside its context.

Cron

Code	Summary	Construct
bynk.cron.bad_params	A cron handler declares more than one parameter, or a non-Int one.	cron_handler
bynk.cron.duplicate_schedule	Two cron handlers declare the same schedule.	cron_handler
bynk.cron.invalid_schedule	A cron expression is not five whitespace-separated fields.	cron_handler
bynk.cron.return_not_effect_result	A cron handler does not return Effect[Result[(), E]].	cron_handler

Effects

Code	Summary	Construct
bynk.effect.bind_in_pure_context	An <- bind was used in a pure (non-effectful) context.	effect_let_stmt
bynk.effect.bind_on_non_effect	An <- bind was applied to a non-Effect value.	effect_let_stmt
bynk.effect.capability_in_pure_context	A capability was used in a pure context.
bynk.effect.cross_context_in_pure_context	A cross-context call was made in a pure context.
bynk.effect.fn_value_in_pure_context	An effectful function value was called in a pure context; like a capability call, it is legal only where the enclosing body is effectful.	call

Exports

Code	Summary	Construct
bynk.exports.capability_not_provided	An exported capability has no provider in its context.	exports_decl
bynk.exports.conflicting_visibility	A type is exported with conflicting visibilities.	exports_decl
bynk.exports.duplicate_export	The same name is exported more than once.	exports_decl
bynk.exports.duplicate_in_clause	A name appears twice in one exports clause.	exports_decl
bynk.exports.undeclared_capability	exports capability names a capability that is not declared.	exports_decl
bynk.exports.undeclared_type	exports names a type that is not declared.	exports_decl

Given capabilities

Code	Summary	Construct
bynk.given.cross_context_unknown_capability	given B.Cap names a capability the consumed context does not export.	given_clause
bynk.given.undeclared_capability	A handler uses a capability it did not declare with given.	given_clause
bynk.given.unknown_capability	given names a capability that does not exist.	given_clause
bynk.given.unused_capability	A given capability is never used (warning).	given_clause

HTTP

Code	Summary	Construct
bynk.http.body_on_get_or_delete	A GET or DELETE handler declares a body parameter.	http_handler
bynk.http.duplicate_route	Two handlers share the same method and route.	http_handler
bynk.http.extra_param	A handler parameter is neither a path parameter nor body.	http_handler
bynk.http.invalid_path	An HTTP route path is malformed.	http_handler
bynk.http.path_param_not_stringy	A path parameter’s type is not constructible from a string.	http_handler
bynk.http.reserved_prefix	A route uses the reserved /_bynk/ prefix.	http_handler
bynk.http.return_not_effect_http_result	An HTTP handler does not return Effect[HttpResult[T]].	http_handler
bynk.http.unbound_path_param	A :name route segment has no matching handler parameter.	http_handler

Lexer

Code	Summary	Construct
bynk.lex.bad_escape	An invalid escape sequence in a string literal.	string_literal
bynk.lex.float_literal_overflow	A float literal does not fit a finite 64-bit float.	float_literal
bynk.lex.integer_overflow	An integer literal is out of range.	number_literal
bynk.lex.unclosed_doc_block	A documentation block is not closed.
bynk.lex.unexpected_character	An unexpected character in the source.
bynk.lex.unterminated_interpolation	An interpolation hole \(…) is not closed on its line.	string_literal
bynk.lex.unterminated_string	A string literal is not terminated.	string_literal

Mock and mocks

Code	Summary	Construct
bynk.mock.arity	Mock[T] was given the wrong number of pin arguments.	mock_expr
bynk.mock.duplicate_target	A mocks target is declared more than once.	mocks_decl
bynk.mock.in_commons_test	mocks used in a commons test, where there is no dependency to inject.	mocks_decl
bynk.mock.literal_violates	A pinned Mock[T] value violates the type’s refinement.	mock_expr
bynk.mock.needs_pin	A bare Mock[T] cannot generate a value (e.g. a Matches string); pin one.	mock_expr
bynk.mock.outside_test	Mock[T] was used outside a test case body.	mock_expr
bynk.mock.pin_not_literal	A Mock[T] pin argument is not a compile-time literal.	mock_expr
bynk.mock.pin_unsupported	A pin was given for a type kind that does not support pinning.	mock_expr
bynk.mock.signature_mismatch	A mocks implementation’s signature does not match the capability.	mocks_decl
bynk.mock.unknown_target	mocks names a capability that is not in scope.	mocks_decl
bynk.mock.unknown_type	Mock[T] names a type that does not resolve.	mock_expr
bynk.mock.unsupported_kind	Mock[T] cannot fabricate a value for this kind of type.	mock_expr

Other

Code	Summary	Construct
bynk.actor.bearer_identity_not_string_constructible	A Bearer actor’s identity is not a string-constructible type.
bynk.actor.bearer_missing_secret	A Bearer actor does not name its signing secret.
bynk.actor.binder_shadows_param	A by actor binder collides with a handler parameter of the same name.
bynk.actor.by_on_agent	A by actor clause was placed on an agent on call handler, which has no actor.
bynk.actor.duplicate_sum_scheme	Two peers in a multi-actor sum share an authentication scheme.
bynk.actor.identity_not_sealed	An actor identity type is not a context-ownable (sealed) value type.
bynk.actor.missing_by_on_http	An HTTP handler lacks the required by actor clause.
bynk.actor.outside_context	An actor was declared outside a context (e.g. in a commons).
bynk.actor.refinement_base_unsupported	A refinement actor’s base is not a Bearer actor (no claims to authorise against).
bynk.actor.refinement_in_sum	A refinement actor appears as a member of a multi-actor sum.
bynk.actor.refinement_predicate_unsupported	A refinement actor’s where predicate is outside the closed claim-predicate set.
bynk.actor.scheme_not_admissible	An actor’s scheme is not admissible on this handler’s protocol.
bynk.actor.signature_identity_unsupported	A Signature actor declared an identity, which is not yet supported.
bynk.actor.signature_missing_header	A Signature actor does not name its signature header.
bynk.actor.signature_missing_secret	A Signature actor does not name its signing secret.
bynk.actor.signature_requires_body	A Signature handler does not take a body parameter.
bynk.actor.signature_tolerance_without_timestamp	A Signature actor set tolerance without a timestamp header.
bynk.actor.sum_requires_binder	A multi-actor sum by clause has no binder to match the resolved actor.
bynk.actor.unknown_actor	A handler’s by clause names an actor that is not declared.
bynk.actor.unknown_scheme	An actor declares an authentication scheme that is not compiler-known.
bynk.actor.unreachable_sum_arm	A multi-actor sum has an arm unreachable after a catch-all (None) peer.
bynk.adapter.consumes_context	An adapter consumed a context; adapter dependencies are adapter-to-adapter.	consumes_decl
bynk.adapter.consumes_requires_selection	An adapter used a whole-unit or aliased consumes; adapters must select capabilities with consumes U { Cap, … }.	consumes_decl
bynk.adapter.disallowed_item	An adapter declared a service, agent, or other item it may not contain.	adapter_decl
bynk.adapter.duplicate_binding	An adapter declared more than one binding clause.	binding_decl
bynk.adapter.no_binding	An adapter declares an external provider but no binding module to supply it.	adapter_decl
bynk.adapter.provider_has_body	A provider inside an adapter has a Bynk body; adapter providers must be external.	provider_decl
bynk.cell.invalid_target	A := write targets something that is not a store Cell field.
bynk.cell.self_reference	A := right-hand side reads the cell being written (a read-modify-write); use .update.
bynk.duration.literal_overflow	A Duration literal (<int>.<unit>) exceeds the representable millisecond range.
bynk.generics.no_bounds	A type parameter carries a bound ([A: …]); bounded generics are not in v0.20a.	fn_decl
bynk.generics.no_generic_types	A type declaration carries a type-parameter list; generic type declarations are not in v0.20a (type parameters belong to functions).	type_decl
bynk.generics.type_arg_mismatch	Inferred or explicit type arguments conflict, have the wrong arity, target a non-generic function, or a type parameter shadows a declared type.	call
bynk.generics.uninferable_type_arg	A generic function’s type parameter could not be inferred from the arguments and was not given explicitly (name[T](…)); a bare generic function also cannot be passed as a value in v0.20a.	call
bynk.held.branch_divergence	Branches of a conditional leave a held value (e.g. Connection[F]) in inconsistent ownership states — one consumes or stores it, another leaves it owned (§2.9.5, real-time track slice 2).
bynk.held.consume_on_borrow	A consuming operation (close/put/take) is called on a borrowed held reference — borrows admit only non-consuming operations like send (§2.9.3, real-time track slice 2).
bynk.held.leak	A held value (Connection[F]) is still owned at scope exit — it must be disposed (stored, closed, or transferred) before the handler returns (§2.9.1, real-time track slice 2).
bynk.held.unsupported_map_op	A held Map[K, Connection] is given an update/upsert — a held resource cannot be transformed by a (Connection) -> Connection function; use put/get/remove (real-time track slice 3b-ii).
bynk.held.unsupported_storage	A held value (Connection[F]) is stored in a Set/Log/Cache — held values may only live in Cell[Option[Connection]] or Map[K, Connection] (§2.9.3, real-time track slice 2).
bynk.held.use_after_consume	A held value (Connection[F]) is used after a consuming operation (close/put/take) ended its lifetime (§2.9.2, real-time track slice 2).
bynk.index.bad_argument	An @indexed argument is not a by: <field> label.
bynk.index.missing	A query filters a map by equality on a field that is not @indexed (a perf-hint warning).
bynk.index.unkeyable_key	An @indexed(by: k) field is not value-keyable.
bynk.index.unknown_key	An @indexed(by: k) field is not a field of the map’s value type.
bynk.index.unused	A declared @indexed(by: k) is never used by an equality filter (a hygiene warning).
bynk.integration.duplicate_participant	A context is listed more than once in a wires clause.	wires_decl
bynk.integration.duplicate_suite	Two integration tests share the same suite name.	integration_decl
bynk.integration.mock_in_integration	mocks is not allowed in an integration test.	mocks_decl
bynk.integration.too_few_participants	An integration test wires fewer than two contexts.	wires_decl
bynk.integration.unknown_participant	A wires clause names something that is not a declared context.	wires_decl
bynk.integration.unwired_dependency	A participant consumes a context that is not wired into the integration test.	integration_decl
bynk.invariant.cross_agent_reference	An invariant predicate references another agent; invariants are per-agent.
bynk.invariant.duplicate_name	An agent declares two invariants with the same name.
bynk.invariant.impure_predicate	An invariant predicate uses an effectful or test-only construct.
bynk.invariant.not_bool	An invariant predicate does not have type Bool.
bynk.lambda.unannotated_param	A lambda parameter has no type annotation in a position where no function type is expected to infer it from.	lambda_expr
bynk.list.deprecated_function	A bynk.list free function (map/filter/find/any/all) is deprecated in favour of the List method form (warning; auto-fixable).
bynk.namespace.reserved	A user unit is named bynk or bynk.*; the bynk root is reserved for the toolchain.
bynk.query.join_key_mismatch	A joinOn/leftJoin left and right key function return different types.
bynk.query.sum_needs_numeric	A sum/average key function does not return a numeric type (Int, Float, or Duration).
bynk.requires.unpinned_dependency	An adapter binding … requires { … } entry has an unpinned version range.	binding_decl
bynk.send.in_pure_context	A ~> send was used in a pure (non-effectful) context.	effect_send_stmt
bynk.send.non_effect	A ~> send was applied to a non-Effect value.	effect_send_stmt
bynk.send.requires_unit	A ~> send targets an operation whose reply is not Effect[()].	effect_send_stmt
bynk.store.annotation_kind_mismatch	A storage annotation is used on a kind it does not apply to (e.g. @ttl on a Map).
bynk.store.annotation_unsupported	A known storage annotation (@ttl/@retain/@indexed/@bounded) is used before the slice that supports it.
bynk.store.cache_needs_clock	A handler performs a Cache operation (TTL expiry reads the clock) without declaring given Clock.
bynk.store.cache_ttl_required	A Cache field is missing its required @ttl(<duration>) annotation (a keyed store with no expiry is a Map).
bynk.store.kind_arity	A storage kind was applied to the wrong number of type arguments (e.g. Cell[A, B]).
bynk.store.kind_unsupported	A known storage kind (Queue) is used before the slice that supports it.
bynk.store.log_needs_clock	A handler calls Log.append (which stamps the current time) without declaring given Clock.
bynk.store.unknown_annotation	A store field carries an annotation outside the closed @indexed/@ttl/@retain/@bounded set.
bynk.store.unknown_kind	A store field’s type is not a known storage kind.
bynk.store.unknown_op	A storage-Map/Set operation is not a recognised entry/membership method.
bynk.target.browser_bundle_only	The browser platform builds only the in-process Bundle topology; --target workers is not a browser build.
bynk.target.vendor_conflict	One deployment unit’s in-process closure uses platform-native capabilities from two mutually-exclusive platforms.	consumes_decl
bynk.target.vendor_required	A deployment unit uses a platform-native capability but the build selects another --platform.	consumes_decl
bynk.ws.message_frame_param	A WebSocket on message handler does not have exactly one parameter of the service’s inbound (in:) frame type — the decoded frame (real-time track slice 3b-iii).
bynk.ws.open_given_unsupported	A WebSocket on open handler declares given capabilities — unsupported at v1, since on Workers the handler runs inside the connection-hosting Durable Object, which has no composition root to supply them (real-time track slice 3b).
bynk.ws.open_transfer_shape	A WebSocket on open handler does not transfer its connection into exactly one agent, so the Workers upgrade has no single Durable Object to route to (real-time track slice 3b).
bynk.ws.route_param_mismatch	A WebSocket on message/on close route parameter does not match the on open parameter at the same position — route values are recovered positionally from the connection, so they must be a type-compatible prefix of the on open parameters (real-time track slice 3b-iii).

Parser

Code	Summary	Construct
bynk.parse.consumes_after_decls	consumes appears after other declarations.	consumes_decl
bynk.parse.empty_agent	An agent body is empty.	agent_decl
bynk.parse.empty_capability	A capability body is empty.	capability_decl
bynk.parse.empty_interpolation	An interpolation hole \(…) contains no expression.
bynk.parse.empty_match	A match has no arms.	match_expr
bynk.parse.empty_mock_body	A mocks body is empty.	mocks_decl
bynk.parse.empty_service	A service body is empty.	service_decl
bynk.parse.expected_agent_key	Expected a key declaration in an agent.	agent_decl
bynk.parse.expected_agent_storage	An agent declares no storage — it has no store fields.
bynk.parse.expected_base_type	Expected a base type.	base_type
bynk.parse.expected_capability_op	Expected a capability operation.	capability_op
bynk.parse.expected_expression	Expected an expression.
bynk.parse.expected_handler	Expected a handler.	handler
bynk.parse.expected_item	Expected a declaration.
bynk.parse.expected_predicate	Expected a refinement predicate.	refinement
bynk.parse.expected_provider_op	Expected a provider operation.	provider_op
bynk.parse.expected_token	Expected a specific token.
bynk.parse.expected_type	Expected a type.
bynk.parse.expected_unit_header	Expected a commons or context header.
bynk.parse.expected_visibility	Expected a visibility keyword.	exports_decl
bynk.parse.exports_after_decls	exports appears after other declarations.	exports_decl
bynk.parse.extra_tokens	Unexpected tokens after an otherwise complete construct.
bynk.parse.generic_arg_count	Wrong number of generic type arguments.	generic_type_ref
bynk.parse.handler_in_agent	A protocol handler (on GET/schedule/message) was declared in an agent.	handler
bynk.parse.invariant_after_handler	An invariant was declared after a handler; invariants precede handlers.
bynk.parse.malformed_float_literal	A float literal is missing a digit on one side of the . (1., .5).	float_literal
bynk.parse.non_associative	A non-associative operator was chained (e.g. a == b == c).	binary_expr
bynk.parse.orphan_doc_block	A documentation block is not attached to a declaration (warning).
bynk.parse.reserved_keyword	A reserved keyword was used as an identifier.	identifier
bynk.parse.self_outside_method	self used outside a method or handler.	self_expr
bynk.parse.storage_after_phase	Agent storage (state / store) is declared after the invariants or handlers.
bynk.parse.unexpected_adapter	An adapter appeared where it is not allowed.
bynk.parse.unexpected_context	A context appeared where it is not allowed.	context_decl
bynk.parse.unexpected_eof	Unexpected end of input.
bynk.parse.unexpected_test	A test appeared where it is not allowed.	test_decl
bynk.parse.unknown_effect_method	An unknown method on Effect.
bynk.parse.unknown_handler_kind	An unknown handler form (expected call, an HTTP method, schedule, or message).	handler
bynk.parse.unknown_predicate	An unknown refinement predicate.	predicate_name
bynk.parse.uses_after_decls	uses appears after other declarations.	uses_decl

Project

Code	Summary	Construct
bynk.project.file_and_directory	A unit exists as both a file and a directory.
bynk.project.inconsistent_commons_name	A source file’s path does not match its declared name.
bynk.project.inconsistent_test_path	A test file’s path does not match its target’s name.
bynk.project.kind_conflict	A name is declared as both a commons and a context.
bynk.project.no_root	No project root could be determined.
bynk.project.no_sources	The project contains no source files.
bynk.project.read_failed	A source file could not be read.

Providers

Code	Summary	Construct
bynk.provider.dependency_cycle	Providers form a capability dependency cycle through given.	provider_decl
bynk.provider.extra_operation	A provides block implements an operation not in the capability.	provider_decl
bynk.provider.missing_operation	A provides block is missing a capability operation.	provider_decl
bynk.provider.outside_context	provides was declared outside a context.	provider_decl
bynk.provider.signature_mismatch	A provides operation’s signature does not match the capability.	provider_decl
bynk.provider.unknown_capability	provides names a capability that does not exist.	provider_decl

Queue

Code	Summary	Construct
bynk.queue.bad_params	An on message handler does not take exactly one message parameter.	queue_handler
bynk.queue.duplicate_consumer	Two on message handlers consume the same queue.	queue_handler
bynk.queue.invalid_name	A from queue("…") binding has an empty queue name.	queue_handler
bynk.queue.return_not_queue_result	An on message handler does not return Effect[QueueResult].	handler

Record spread

Code	Summary	Construct
bynk.record_spread.field_type_mismatch	A record-spread override has the wrong type for the field.	record_spread
bynk.record_spread.non_record_base	The base of a record spread is not a record.	record_spread
bynk.record_spread.type_mismatch	A record spread’s base is a different record type.	record_spread
bynk.record_spread.unknown_field	A record spread overrides a field the record does not have.	record_spread

Refinement

Code	Summary	Construct
bynk.refine.literal_violates	A literal does not satisfy the refined type’s predicate.	refined_type

Resolution

Code	Summary	Construct
bynk.resolve.ambiguous_variant	A variant name is ambiguous across several sum types.
bynk.resolve.arity_mismatch	A function was called with the wrong number of arguments.	call
bynk.resolve.duplicate_actor	Two actors share a name.
bynk.resolve.duplicate_agent	Two agents share a name.	agent_decl
bynk.resolve.duplicate_capability	Two capabilities share a name.	capability_decl
bynk.resolve.duplicate_field	A record declares a field twice.	record_type
bynk.resolve.duplicate_field_init	A record construction initialises a field twice.	record_construction
bynk.resolve.duplicate_fn	Two functions share a name.	fn_decl
bynk.resolve.duplicate_method	Two methods share a name.	fn_decl
bynk.resolve.duplicate_param	A parameter name is repeated.	param
bynk.resolve.duplicate_provider	A capability is provided more than once.	provider_decl
bynk.resolve.duplicate_service	Two services share a name.	service_decl
bynk.resolve.duplicate_type	Two types share a name.	type_decl
bynk.resolve.duplicate_variant	A sum type declares a variant twice.	sum_type
bynk.resolve.fn_without_call	A function was referenced without being called.
bynk.resolve.let_shadows_fn	A let binding shadows a function.	let_stmt
bynk.resolve.let_shadows_type	A let binding shadows a type.	let_stmt
bynk.resolve.method_unknown_type	A method is defined on an unknown type.
bynk.resolve.missing_field	A record construction omits a required field.	record_construction
bynk.resolve.name_conflict	Two declarations share a name.
bynk.resolve.not_a_record_type	Record syntax was used on a non-record type.	record_construction
bynk.resolve.opaque_record_construction	An opaque type was constructed with record syntax.	record_construction
bynk.resolve.param_as_function	A value (such as a parameter) was called as a function.	call
bynk.resolve.recursive_record_field	A record directly contains a field of its own type.	record_type
bynk.resolve.self_outside_method	self referenced outside a method or handler.	self_expr
bynk.resolve.type_as_function	A type name was called as if it were a function.	call
bynk.resolve.type_in_expr	A type name was used where a value is expected.
bynk.resolve.unconsumed_context	A context’s service was called without a consumes declaration.	consumes_decl
bynk.resolve.unknown_field	Accessed a field the record does not have.	field_access
bynk.resolve.unknown_function	Called a function that does not exist.	call
bynk.resolve.unknown_name	Referenced a name that is not in scope.
bynk.resolve.unknown_static_member	Referenced an unknown static member (e.g. T.x).	field_access
bynk.resolve.unknown_type	Referenced a type that does not exist.

Services

Code	Summary	Construct
bynk.service.missing_from	A from-less service has a handler other than on call.	service_decl
bynk.service.mixed_protocols	A service mixes handler forms that do not match its from <protocol>.	service_decl
bynk.service.outside_context	A service was declared outside a context.	service_decl
bynk.service.return_not_effect	A service handler’s return type is not an Effect.	service_decl
bynk.service.unknown_protocol	A from <protocol> names an unknown protocol (e.g. a transport like Kafka).	service_decl
bynk.service.websocket_header	The from WebSocket header is malformed — it binds frame types as WebSocket(in: <type>, out: <type>) (real-time track slice 3).
bynk.service.websocket_multiple	A context holds more than one from WebSocket service — at v1 the Workers upgrade routes by the Upgrade: websocket header alone, so one WebSocket service per context (real-time track slice 3b).
bynk.service.websocket_open_arity	A from WebSocket service must hold exactly one on open handler (the edge upgrade), and at most one on message (inbound) and one on close (real-time track slice 3/3b-iii).

Tests

Code	Summary	Construct
bynk.test.duplicate_case_name	Two test cases share a description.	test_case
bynk.test.unknown_target	A test block targets a unit that does not exist.	test_decl

Type checking

Code	Summary	Construct
bynk.types.ambiguous_constructor	Ok/Err is ambiguous between Result and HttpResult; qualify it.
bynk.types.argument_mismatch	A function argument has the wrong type.	call
bynk.types.call_arity	A function value was applied with the wrong number of arguments.	call
bynk.types.cannot_infer_option_type_param	The value type of None could not be inferred.	none_expr
bynk.types.cannot_infer_result_type_params	The type parameters of a Result could not be inferred.
bynk.types.constructor_arity	A variant constructor got the wrong number of arguments.
bynk.types.constructor_base_mismatch	A .of constructor was given an argument of the wrong base type.
bynk.types.duplicate_variant_arm	A match has two arms for the same variant.	match_arm
bynk.types.empty_refinement	A refinement admits no values (contradictory predicates).	refinement
bynk.types.err_value_mismatch	An Err payload has the wrong type.	err_expr
bynk.types.field_access_on_non_record	Field access on a value that is not a record.	field_access
bynk.types.field_refinement_not_base	An inline field refinement requires a base or refined type.	record_field
bynk.types.field_value_mismatch	A record field was given a value of the wrong type.	record_construction
bynk.types.function_at_boundary	A function type appeared in a serialisable or boundary position (a record field, sum payload, service/agent handler signature, capability operation signature, agent state field, or agent key); functions cannot serialise or cross a boundary.	function_type_ref
bynk.types.held_at_boundary	A held value (Connection[F]) appears in a serialisable or boundary position — a held resource is built and disposed in place, never persisted or sent across a boundary (§2.9, real-time track slice 2).
bynk.types.held_not_comparable	A held value (Connection[F]) is compared with ==/!= — held values have identity, not value-equality (§2.9.3, real-time track slice 2).
bynk.types.if_branch_mismatch	The branches of an if have different types.	if_expr
bynk.types.if_non_bool_cond	An if condition is not a Bool.	if_expr
bynk.types.interpolation_non_scalar	An interpolation hole holds a value with no string form.
bynk.types.invalid_regex	A Matches predicate contains an invalid regular expression.	refinement
bynk.types.inverted_range	An InRange predicate has its bounds inverted.	refinement
bynk.types.is_base_mismatch	An is refinement check is applied to a value of the wrong base type.	is_expr
bynk.types.is_non_sum	is was applied to a value that is not a sum type.	is_expr
bynk.types.is_unknown_variant	is names a variant the type does not have.	is_expr
bynk.types.json_uncodable	A Json.encode/Json.decode target type cannot pass through the typed JSON codec (functions, effects, error builtins).	method_call
bynk.types.key_not_orderable	A sortBy/min/max key function does not return an orderable type (Int, Float, String, Duration, or Instant).
bynk.types.lambda_mismatch	A lambda’s parameter count, parameter annotations, or body type do not match the expected function type.	lambda_expr
bynk.types.let_annotation_mismatch	A let value does not match its type annotation.	let_stmt
bynk.types.list_element_mismatch	A list-literal element has a different type from the list’s element type.	list_literal
bynk.types.match_arm_mismatch	A match arm has a different type from the others.	match_arm
bynk.types.match_non_sum_discriminant	match was applied to a value that is not a sum type.	match_expr
bynk.types.method_arity	A method was called with the wrong number of arguments.	method_call
bynk.types.method_not_found	Called a method the type does not have.	method_call
bynk.types.method_on_non_named_type	A method was called on a built-in type that has no methods.	method_call
bynk.types.mixed_pattern_bindings	A pattern mixes named and positional bindings.	variant_pattern
bynk.types.negative_length	A length predicate was given a negative value.	refinement
bynk.types.no_numeric_coercion	Int and Float were mixed without an explicit conversion — in an operation or in refinement bounds.	binary_expr, refinement
bynk.types.non_exhaustive_match	A match does not cover every variant.	match_expr
bynk.types.ok_value_mismatch	An Ok payload has the wrong type.	ok_expr
bynk.types.opaque_raw_outside	.raw on an opaque type was used outside its defining commons.	field_access
bynk.types.opaque_record_construction	An opaque type was constructed with record syntax.	record_construction
bynk.types.opaque_unsafe_outside	.unsafe on an opaque type was used outside its defining context.	field_access
bynk.types.pattern_arity	A pattern binds the wrong number of payload fields.	variant_pattern
bynk.types.pattern_type_mismatch	A pattern’s type does not match the matched value.	variant_pattern
bynk.types.predicate_base_mismatch	A predicate does not apply to the type’s base (e.g. a string predicate on an Int).	refinement
bynk.types.query_at_boundary	A Query type appears in a storable or boundary-crossing position — a query is built and executed in place, never persisted or sent (ADR 0115).
bynk.types.question_error_mismatch	? propagates an error type incompatible with the function’s.	question_expr
bynk.types.question_on_non_result	? was applied to a non-Result value.	question_expr
bynk.types.question_outside_result	? used in a function that does not return a Result.	question_expr
bynk.types.return_mismatch	A returned value does not match the declared return type.
bynk.types.some_value_mismatch	A Some payload has the wrong type.	some_expr
bynk.types.stream_at_boundary	A Stream type appears in a storable or boundary-crossing position — a stream is a live value-over-time source, never persisted or sent across a boundary (real-time track slice 0).
bynk.types.stream_not_comparable	A Stream value is compared with ==/!= — a stream is a live value-over-time source, not a comparable value (real-time track slice 0).
bynk.types.type_mismatch	Two types that were required to match did not.
bynk.types.uninferable_element_type	An empty [] (or List.empty() / Map.empty()) has no expected type to infer its element type from.	list_literal
bynk.types.unkeyable_distinct	A distinct/distinctBy element or key is not value-keyable (String, Int, or a refined/opaque type over them).
bynk.types.unkeyable_map_key	A Map key type is not value-keyable (String, Int, or a refined/opaque type over them).	generic_type_ref
bynk.types.unknown_field	Referenced a field the record type does not declare.	field_access
bynk.types.unknown_pattern_field	A pattern names a field the variant does not have.	variant_pattern
bynk.types.unknown_static_member	Referenced an unknown static member on a type.	field_access
bynk.types.unknown_variant_in_pattern	A pattern names a variant the sum type does not have.	variant_pattern
bynk.types.unreachable_arm	A match arm is unreachable.	match_arm
bynk.types.variant_arity	A variant constructor got the wrong number of payload values.
bynk.types.variant_missing_payload	A variant requiring a payload was used without one.
bynk.types.variant_payload_mismatch	A variant payload has the wrong type.

Uses

Code	Summary	Construct
bynk.uses.name_conflict	A uses name collides with another name.	uses_decl
bynk.uses.self_reference	A commons uses itself.	uses_decl
bynk.uses.target_is_context	uses targets a context instead of a commons.	uses_decl
bynk.uses.unknown_commons	uses names a commons that does not exist.	uses_decl