Diagnostics#

When the code generator cannot make sense of a model it reports a message with a stable code. The codes are grouped by what went wrong, so the first digits already tell you where to look:

Range	Area
`E1001`, `E2008`, `M10xx`	State machine structure — reused from the UML backends
`E30xx`	Type references — a name that should denote a type
`E31xx`	Features and usages — attributes, ports, actions, flow nodes
`W31xx`	Warnings — the model is accepted, but probably not what you meant

E… prevents usable code from being produced. W… and M… let generation continue.

Type references#

Code	Message	Typical cause
`E3001`	unresolved type ‘X’	Typo, missing import, or the type lives in another file that is not reachable from the primary one
`E3002`	ambiguous type ‘X’	Two wildcard imports bring in the same name — qualify it (`Pkg::X`)
`E3003`	type ‘X’ has wrong kind	e.g. an item definition used where a port definition is required
`E3004`	type ‘X’ is not visible	The type exists but is `private` in the package that owns it

Features and usages#

Code	Message	Typical cause
`E3101`	unresolved feature ‘X’	The attribute, port or part named here does not exist on the part or any of its base parts
`E3103`	feature ‘X’ has wrong kind	e.g. an attribute used where a port is expected
`E3105`	cannot connect … / incompatible connection types	A `connect` joins two `in` ports, two `out` ports, or ports of different types
`E3107`	action usage ‘X’ has no definition	`entry X;` or `do action X;` names an action that is not declared on the part or its base parts
`E3109`	action usage ‘X’ binds n parameters but the definition declares m	The call site passes the wrong number of parameters, or an `in`/`out` direction does not match
`E3111`	cannot resolve performer chain ‘X’	A segment of `a.b.setOn` does not exist — or the chain ends on a collection, which cannot be performed on. Perform on a named member instead
`E3113`	flow node ‘X’ is used as K1 but was already declared as K2	The same name appears twice in one action flow with different meanings
`E3119`	cannot resolve port ‘X’ used in a send action	The port is not declared on the part or any of its base parts

Warnings#

Code	Message	What to do
`W3115`	‘x’ adds values with different units	Units are normalized but never converted. Either write both operands in the same unit, or ignore the warning if the mix is intended. Only `+` and `-` are checked — `U*I` is ordinary physics and stays quiet. See Attributes
`W3117`	‘x’ declares a new empty action	You wrote `entry action x;` where an action `x` already exists. That declares a second, empty one. To perform the existing action write `entry x;` or `entry references x;`. See States

State machine structure#

These come from the shared state machine backend and also appear for UML models.

Code	Meaning
`E1001`	A default state is missing. With an init state leading into a choice, the `else` path is usually the one that is absent
`E2008`	A transition starts in a state that is not known in this machine — check for a typo in the source state, or a transition that starts in a history state
`M1024` / `M1032`	A state is not reachable — no transition leads to it
`M1054`	A state has no outgoing transition, which usually indicates a dead end

Reading the location#

Messages carry the source position where available:

tl.sysml:212:9: W3117: 'setYellow' declares a new empty action.
                To perform an existing one write 'setYellow;' or 'references setYellow'.

Run the generator with -d to get the symbol table dump alongside the diagnostics; it shows how each name was classified (def, usage, use+def, connect) and which references were bound. That is usually the fastest way to see why a name did not resolve.

Cross-checking against the reference implementation#

The generator accepts a few constructs that stricter tools reject, and it cannot detect every modelling error. If a model generates cleanly but a SysML editor complains, the editor is usually right. See Tooling for how to validate a model against the SysML v2 reference implementation.