no-duplicate-type-param-tags

Disallow duplicate generic tags (@typeParam / @template) for the same type parameter name.

Targeted pattern scope

This rule checks TypeDoc comments on generic declarations (functions, methods, classes, interfaces, and type aliases).

What this rule reports

This rule reports when a type parameter name is documented multiple times in one comment block.

Why this rule exists

Duplicate generic docs introduce conflicting descriptions and reduce documentation clarity for API consumers.

❌ Incorrect

/**
 * Identity helper.
 * @typeParam TValue Value type.
 * @template TValue Duplicate value type.
 * @param value Input value.
 * @returns Same value.
 */
export function identity<TValue>(value: TValue): TValue {
    return value;
}

✅ Correct

/**
 * Identity helper.
 * @typeParam TValue Value type.
 * @param value Input value.
 * @returns Same value.
 */
export function identity<TValue>(value: TValue): TValue {
    return value;
}

Behavior and migration notes

The rule reports duplicates but does not autofix, since choosing which content to keep is semantic.

ESLint flat config example

import typedocPlugin from "eslint-plugin-typedoc";

export default [
    {
        plugins: { typedoc: typedocPlugin },
        rules: {
            "typedoc/no-duplicate-type-param-tags": "error",
        },
    },
];

When not to use it

Disable only if your team intentionally duplicates generic docs (rare and usually accidental).

Package documentation

TypeDoc package documentation:

• TypeDoc @typeParam tag

Further reading

Rule catalog ID: R016

• TypeDoc comments and tags

Adoption resources

• Pair with require-type-param-tags and no-extra-type-param-tags for strong generic-doc consistency.