Explicit `never` return type in `catch` block & condition in `finally` marks the whole `finally` block as unreachable

[d-fischer]

🔎 Search Terms

finally, unreachable, condition, never

🕗 Version & Regression Information

• This builds fine in 3.2,
• produces a type error regarding the return type in 3.3 through 3.6,
• and starting 3.7, including the latest native preview, it produces the unreachable code error

⏯ Playground Link

https://www.typescriptlang.org/play/?noImplicitAny=false&ts=5.9.3#code/MYewdgzgLgBATgUwA4jlAXDAFAzBDMATwEoYBeAPhjAQDcE5zsFjMb7HKYBvAKBhhQAFnBAB3GAgDcvAL4zeoSLABmIEEzwRCYYNlYwACqIC2ASwgIAPGACuJgEYMqXPgKhxCPfgPgIotnBgMADMMgKyMMB4UMBCzKRuvogoaDjE4TCRKmZgeAA2+V5JAmYq2B62LN6+vkoQIPkIAHT5IADmWABEQghCXRk+ET6yclJAA

💻 Code

function report(e): never {
  throw e;
};

const foo = async (): Promise<number> => {
  try {
    return 3;
  } catch (e) {
    report(e);
  } finally {
    if (true) {
      console.log("heh");
    }
  }
};

🙁 Actual behavior

test.ts:11:5 - error TS7027: Unreachable code detected.

11     if (true) {
       ~~~~~~~~~~~
12       console.log("heh");
   ~~~~~~~~~~~~~~~~~~~~~~~~~
13     }
   ~~~~~

test.ts:12:7 - error TS7027: Unreachable code detected.

12       console.log("heh");
         ~~~~~~~~~~~~~~~~~~~

🙂 Expected behavior

Builds fine.

Additional information about the issue

This error vanishes if I do any of the following:

• Remove the explicit never return type of reportError (although that resurfaces the return type error)
• Remove the call to reportError entirely, or the whole catch block
• Remove the if condition from the finally block, but leave in the console.log call

I found a similar issue #61259, but it does not include a catch block, which is integral to the issue here - although the issues might still be related. Similarly to that issue, the finally block also becomes reachable when adding another return to the catch block, but it is itself unreachable.

[Andarist]

#61265 fixes this too