emberjs/ember.js · error · Error

Attempted to resolve a modifier in a strict mode template, b

Error message

Attempted to resolve a modifier in a strict mode template, but it was not in scope: ${name}

What it means

Error "Attempted to resolve a modifier in a strict mode template, but it was not in scope: ${name}" thrown in emberjs/ember.js.

Source

Thrown at packages/@glimmer/opcode-compiler/lib/opcode-builder/helpers/resolution.ts:226

      scopeValues,
      symbols: { lexical },
    } = meta;
    let definition = expect(scopeValues, 'BUG: scopeValues must exist if template symbol is used')[
      expr[1]
    ];

    then(constants.modifier(definition as object, lexical?.at(expr[1]) ?? undefined));
  } else if (type === SexpOpcodes.GetStrictKeyword) {
    let {
      symbols: { upvars },
    } = assertResolverInvariants(meta);
    let name = unwrap(upvars[expr[1]]);
    let modifier = resolver?.lookupBuiltInModifier?.(name) ?? null;

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

      throw new Error(
        `Attempted to resolve a modifier in a strict mode template, but it was not in scope: ${name}`
      );
    }

    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion -- @fixme
    then(constants.modifier(modifier!, name));
  } else {
    let {
      symbols: { upvars },
      owner,
    } = assertResolverInvariants(meta);
    let name = unwrap(upvars[expr[1]]);
    let modifier = resolver?.lookupModifier?.(name, owner) ?? null;

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

      throw new Error(

View on GitHub (pinned to 26f97246a8)

When it happens

Trigger: Thrown at packages/@glimmer/opcode-compiler/lib/opcode-builder/helpers/resolution.ts:226 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/3ecb80095f52c45e. Report an issue: GitHub.