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`, `E32xx`	Features and usages — attributes, ports, actions, flow nodes, signals, units
`W31xx`, `W32xx`	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
`E3231`	port ‘X’ of part ‘P’ is already delegated to ‘a.b’	A `bind` or `connect` between a boundary port and a port inside it stands for is refused because the boundary port already stands for another port. A delegation makes its two ends one feature, so it needs exactly one port inside. See Ports
`E3245`	port ‘X’ of part ‘P’ and ‘a.b’ are delegated to each other but face opposite ways	One of the two receives what the other sends. A delegated port carries the direction of the port it stands for — give both the same direction
`E3246`	port ‘X’ of part ‘P’ is typed by ‘T’ and ‘a.b’ by ‘U’	A delegation makes the two ports one feature, which needs one port type
`E3248`	’event_’ / ’eventQueue_’ is reserved for the events the state machine of ‘P’ processes	A machine that accepts signals keeps the current event and its queue under these names. Rename the model’s feature
`E3249`	‘accept E::lit’ names an enumeration literal, not a type	A trigger accepts an occurrence of a type. Declare the event as one (`attribute def lit;`) and write `accept lit`, or test the value in a guard (`if msg == E::lit`). See States

Units and durations#

Code	Message	Typical cause
`E3250`	‘accept after 500 [ms]’: ‘ms’ is not declared	SI declares no prefixed second. Declare the unit in the model once — the message shows the declaration to write. See States
`E3251`	‘x’ is not a DurationValue, which is what a time trigger waits for	An `accept after` names a number or a feature without a duration unit. Give it one, as in `x [s]`
`E3254`	‘xs[2]’: a bracket after a value is its measurement reference	In SysML a bracket after a value names its unit. To index a collection write `xs#(2)`

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
`W3210`	‘a := b’ assigns Real to Integer, which discards the fraction	The model binds a real value to an integer feature. Declare the attribute `Real`, or round explicitly. Reported against the model rather than left to a C++ compiler, which mentions it only on some toolchains
`W3171`	calc ‘X’ ends in an expression but declares no result	The result type is not inferred: write `return : <type>;` beside the expression. See Calculations
`W3173`	calc ‘X’ states its result twice	The calculation gives both a `return … = value` and a trailing expression. The declared value is the one generated; drop the other
`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
`W3214`	‘send … via p’ in ‘P’ goes against the port’s direction	The item’s feature is `in` (or `out`) in the port definition, possibly turned round by a conjugated port (`~`), so the port receives what the model sends through it, or sends what it accepts. A send needs the feature `out` at that port, an accept needs it `in`
`W3212`	‘accept x : T’ cannot bind ‘x’	The machine has an event enum of its own and receives only the event’s value, not the item’s data. The transition still fires; accept through a port (`via`) to read the item
`W3213`	port ‘p’ is read by the state machine of ‘P’ and by action ‘a’	Each arriving element reaches only one of the two. Read the port in one place
`W3172`	the sequence ’(…)’ of ‘xs’ is parsed and not generated	A collection is filled from the members it declares; write `( )` for an empty one
`W3303`	n line(s) could not be routed around the boxes and were drawn straight through them	Only from `-l svg`. The drawing is still written, but those lines cross whatever lies between their ends instead of going around it, which reads as a mistake in the model rather than in the picture. Usually a sign that the boxes leave too little room - drawing with fewer compartments (`-pc`) or less depth (`-pcd`) gives the router space

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 with a SysML editor#

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 the editors and graphical environments that validate a model against the language itself.