emberjs/ember.js · error · Error

Attempted to resolve a ${type} in a strict mode template, bu

Error message

Attempted to resolve a ${type} in a strict mode template, but that value was not in scope: ${meta.symbols.upvars![expr[1]] ?? '{unknown variable}'}

What it means

Error "Attempted to resolve a ${type} in a strict mode template, but that value was not in scope: ${meta.symbols.upvars![expr[1]] ?? '{unknown variable}'}" thrown in emberjs/ember.js.

Source

Thrown at packages/@glimmer/opcode-compiler/lib/opcode-builder/helpers/resolution.ts:444

  expr: Expressions.GetStrictFree,
  resolver: Nullable<ClassicResolver>,
  meta: BlockMetadata,
  constants: ResolutionTimeConstants,
  type: string
): number {
  let {
    symbols: { upvars },
  } = assertResolverInvariants(meta);

  let name = unwrap(upvars[expr[1]]);
  let helper = resolver?.lookupBuiltInHelper?.(name) ?? null;

  if (DEBUG && helper === null) {
    assert(!meta.isStrictMode, 'Strict mode errors should already be handled at compile time');

    // Keyword helper did not exist, which means that we're attempting to use a
    // value of some kind that is not in scope
    throw new Error(
      `Attempted to resolve a ${type} in a strict mode template, but that value was not in scope: ${
        // eslint-disable-next-line @typescript-eslint/no-non-null-assertion -- @fixme
        meta.symbols.upvars![expr[1]] ?? '{unknown variable}'
      }`
    );
  }

  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion -- @fixme
  return constants.helper(helper!, name);
}

View on GitHub (pinned to 26f97246a8)

When it happens

Trigger: Thrown at packages/@glimmer/opcode-compiler/lib/opcode-builder/helpers/resolution.ts:444 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of emberjs/ember.js@26f97246a8 (2026-09-01). Data as JSON: /api/errors/4a2120b0a89ca021. Report an issue: GitHub.