Why am I getting a "Variable foo is declared in case [...] Reference error when accessing" warning?

Minimal example I have is this (it's TypeScript, if it makes a difference):

switch (something) {
    case 1:
        switch (something_else) {
            case "a":
                const foo = 123;
                const bar = foo * 2;
                break;
            case "b":
                const foo = 456;
                const bar = foo * 2;
        }
        break;
    case 2:
        const foo = "foo";
        break;
}

I get the following warning:

However, I can't see any problem; there is no switch fallthrough, the code is not in a loop, so there is no chance of accidentally using a variable declared in a different switch clause; is this an overzealous static code analyzer, or is the code at fault?

Thanks in advance!