Lint rules

Every rule the linter ships, with a page each. A page says what the rule checks and shows an example message and an example form in FSH, with the lines the rule reports highlighted. sdc-lint explain <rule-id> prints the full documentation: why the rule matters, how to fix what it reports and what it cannot see.

Each example is one of the rule's lint cases: a minimal form in YAML, compiled by SUSHI. Testing rules with lint cases explains how they are written and checked.

Core rules

The sdc rules check the expressions of a Questionnaire against the SDC specification and the FHIRPath engine. They run by default, at the severity shown, which a config can change (Configuration). lint/stale-suppression checks the suppressions in the config.

Rule	Default	Reports
sdc/dependency-cycle	warning	Reports declarations whose expressions reference each other in a cycle.
sdc/duplicate-declaration	error	Reports a name declared more than once on one item or on the root.
sdc/external-expression	info	Reports an expression whose content is only behind a reference.
sdc/fragment-parse-error	error	Reports a FHIRPath expression embedded in an x-fhir-query that does not parse.
sdc/language-not-allowed	error	Reports an expression language that SDC does not allow at its location.
sdc/language-not-in-value-set	warning	Reports an expression language that FHIR R4 and R5 do not define.
sdc/parse-error	error	Reports a FHIRPath expression that does not parse.
sdc/query-syntax	error	Reports an x-fhir-query that is not a FHIR search.
sdc/reserved-name	error	Reports a declaration of a name that FHIRPath, FHIR or SDC defines.
sdc/shadowed-declaration	info	Reports a name an item declares that an ancestor item or the root also declares.
sdc/uncatalogued-expression	info	Reports an expression in a place the linter does not recognise.
sdc/undefined-variable	error	Reports a %name that is not available where it is used.
sdc/unknown-function	error	Reports a call to a function that fhirpath.js does not implement.
sdc/unresolved-linkid	warning	Reports a literal linkId that no item in the Questionnaire has.
sdc/unused-declaration	warning	Reports a variable that no expression references.
lint/stale-suppression	warning	Reports a suppression that is no longer needed.

Smart Forms rules

The smart-forms rules report where Smart Forms behaves differently from SDC, in the versions selected in compat. They run only when the plugin is listed in an .mjs config (The Smart Forms plugin).

Rule	Default	Reports
smart-forms/unsupported-expression-language	error	Reports an expression Smart Forms ignores because of its language.
smart-forms/expression-evaluated-as-fhirpath	error	Reports an expression Smart Forms evaluates as FHIRPath whatever its language.
smart-forms/questionnaire-variable-unavailable	error	Reports a reference to %questionnaire or %qitem, which Smart Forms does not supply.
smart-forms/unsupported-query-embedding	error	Reports a {{…}} embedding in an x-fhir-query that Smart Forms population does not fill as written.
smart-forms/variable-name-collision	error	Reports a name declared on two elements, or named like a sourceQueries result, which Smart Forms stores as one value.
smart-forms/repeating-group-variable	warning	Reports a variable on or below a repeating group whose value differs between repetitions, of which Smart Forms keeps one.
smart-forms/named-expression-not-referenceable	error	Reports a reference to a named expression that Smart Forms does not make available to other expressions.
smart-forms/forward-variable-reference	warning	Reports a variable that references a variable or itemPopulationContext that Smart Forms evaluates after it when it prefills the form.
smart-forms/unsupported-template-extract-context	error	Reports a templateExtractContext Smart Forms ignores because it is not a valueString.