broken unicode escape sequence in jsx

[scottbessler]

Steps to reproduce

tsconfig.json

{
    "compilerOptions": {
        "outDir": "./dist",
        "declaration": true,
        "moduleResolution": "node",
        "strict": true,
        "skipLibCheck": true,
        "jsx": "react-jsx"
    }
}

repro.tsx

export const Repro = () => {
    return (<div><span>⚠</span>
        ⚠
    </div>)
}

Behavior with typescript@5.8

> tsc
> grep children dist/repro.js
    return ((0, jsx_runtime_1.jsxs)("div", { children: [(0, jsx_runtime_1.jsx)("span", { children: "\u26A0" }), "\u26A0"] }));

Behavior with tsgo

> tsgo
> grep children dist/repro.js
    return (jsx_runtime_1.jsxs("div", { children: [jsx_runtime_1.jsx("span", { children: "\u26A0" }), "\uFFFD"] }));

Its worth noting that the issue happens with the unicode character on a line by itself but not when there is other stuff in the same line.

[jakebailey]

Probably related to #1701 but, why have you done this? 😭

[scottbessler]

Probably related to #1701 but, why have you done this? 😭

Its actually a CLI tool using Ink, and its a status icon. :)

[jakebailey]

I see, you're saying it's literally https://www.compart.com/en/unicode/U+26A0.

[scottbessler]

I see, you're saying it's literally https://www.compart.com/en/unicode/U+26A0.

Well, it happens to multiple characters, but yeah that was one of the literals I was using.

[jakebailey]

Yeah, it's just a bug then, this is a valid character so not sure where it's gone wrong.