tagged/named rest parameter participating in circular reference causes error

[dragoncoder047]

🔎 Search Terms

named tuple element rest recursive circularly references union unions

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about everything and didn't find anything relevant

⏯ Playground Link

https://www.typescriptlang.org/play/?esModuleInterop=false&target=99&jsx=0&noFallthroughCasesInSwitch=false&ts=6.0.0-dev.20260416&noUnusedLocals=true&noUnusedParameters=true&noUncheckedIndexedAccess=true#code/KYDwDg9gTgLgBDAnmYcDiEIBMAiEDGActqgLwBQcVcAPnAM4xQCWAdgOaXV0DaARMz4AaOADpxGbHiIkeAXTlcqvPgBtBItllAAuOKwCuAWwBGwKCPGjJuAsW3y5AbnLlQkWAmSoAQgENbGW0ARjgKaloGJjZOCJUNMXEYP3Z2YCw9f0D7YGDHcgB6AoiSiIA9CsqKpUj+dWE4LV19YzMLRNEs6Ry8hRc3cGh4JBQ4LrsSACYwmrpGFg5ZuH4Eq3Gg4En8uOW1BKaQPUNTc0sklLSMsYDuqccXItKn5+eqqvIgA

💻 Code

export type GoodDocNode =
    | string
    | ["i", ...GoodDocNode[]]
    | ["li", index: number, ...GoodDocNode[]];

export type BadDocNode1 =
    | string
    | ["i", ...tagged: BadDocNode1[]]
//             ^^^^^^^^
    | ["li", index: number, ...BadDocNode1[]];

export type BadDocNode2 =
    | string
    | ["i", ...BadDocNode2[]]
    | ["li", index: number, ...tagged: BadDocNode2[]];
//                             ^^^^^^^^

🙁 Actual behavior

Error:

Type alias 'BadDocNode1' circularly references itself.
Type alias 'BadDocNode2' circularly references itself.

🙂 Expected behavior

No errors, because the only differences between the two is the name on the rest parameter in the tuple, nothing structurally is different.

Additional information about the issue

No response