# Missing type information in \`mojo doc\` JSON for parametric aliases (new feature in nightly)

**URL:** <https://forum.modular.com/t/missing-type-information-in-mojo-doc-json-for-parametric-aliases-new-feature-in-nightly/1916>\
**Category:** Mojo\
**Created:** [July 7, 2025, 8:06am UTC](https://forum.modular.com/t/missing-type-information-in-mojo-doc-json-for-parametric-aliases-new-feature-in-nightly/1916 "2025-07-07T08:06:01Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![mlange-42](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/mlange-42/32/179_2.png) [@mlange-42](https://forum.modular.com/u/mlange-42)\
**Post date:** [July 7, 2025, 8:06am UTC](https://forum.modular.com/t/missing-type-information-in-mojo-doc-json-for-parametric-aliases-new-feature-in-nightly/1916/1 "2025-07-07T08:06:01Z")

</div>

Given this example parametric alias:

```mojo
alias ParametricAlias[x: Int]: Int = x + 1

```

It is currently not possible to reconstruct the signature from the `mojo doc` JSON.

### Actual behavior

In the JSON, the alias looks like this:

```json
{
    "deprecated": "",
    "description": "",
    "kind": "alias",
    "name": "ParametricAlias",
    "parameters": [
        {
            "description": "",
            "kind": "parameter",
            "name": "x",
            "passingKind": "pos_or_kw",
            "type": "Int"
        }
    ],
    "summary": "A parametric alias",
    "value": "(x + 1)"
}

```

While the type of the parameter is provided, the type of the alias itself is missing.

### Expected behavior

Provide the type of the alias in the `mojo doc` JSON.  
Alternatively, provide the full alias signature as a field of the JSON.

Filed a bug report: [#4980](https://github.com/modular/modular/issues/4980)

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex001/uploads/modular/original/1X/2751e0fbdc595a99718b216730957e9db4448cfd.jpeg) [@system](https://forum.modular.com/u/system)\
**Post date:** [January 3, 2026, 8:06am UTC](https://forum.modular.com/t/missing-type-information-in-mojo-doc-json-for-parametric-aliases-new-feature-in-nightly/1916/2 "2026-01-03T08:06:36Z")

</div>

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