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Severity: warning
Category: Keywords
Stage: Stage 1

Description

SJS reserves a set of identifiers for current or planned language features. Using one of these reserved words as a variable name, function name, parameter name, or property name is syntactically accepted today, but will become a parse error in a future SJS version when the keyword is activated.

Reserved / future keywords that trigger this warning include (non-exhaustive):

where, effect, region, struct, opaque, macro, trait, impl, yield (outside generator context), async (outside async context), await (outside async context).

Example

// ✗ warning
let where = "home"             // SJS-W004 — `where` is a reserved SJS keyword
function struct() { }          // SJS-W004 — `struct` is a reserved SJS keyword

const effect = () => console.log("side effect")  // SJS-W004

Suppression / Fix

Rename the identifier to a non-reserved name:

// ✓ correct
let location = "home"
function buildStruct() { }

const runEffect = () => console.log("side effect")

If the identifier is a property key in an object literal (not a binding), the warning is suppressed because property keys are not evaluated as keyword tokens:

// ✓ correct — property key, not a binding
const config = { where: "home" }

Related codes

  • SJS-E008 — use of a currently-active reserved keyword in an invalid position
Documentation