Throw in catch causes type narrowing in finally block

[markusjohnsson]

TypeScript Version: 3.7.x-dev.201xxxxx
3.6,
3.7-beta

Search Terms:
try catch finally never

Code

function f() {
    let a: number | null = null;
    try {
        a = 123;
        return a;
    }
    catch (e) {
        throw e;  // remove line and error disappears
    }
    finally {
        console.log(a); // works fine, logs 123
        if (a != null && a.toFixed(0) == "123") { 
             // Property 'toFixed' does not exist on type 'never'.(2339)
        }
    }
}

f();

Expected behavior:
a should have type number | null in the finally block.

Actual behavior:
a has type null in the finally block and narrowing with a != null it becoms never

Playground Link:
http://www.typescriptlang.org/play/index.html?ts=3.7-Beta&ssl=1&ssc=1&pln=20&pc=5#code/GYVwdgxgLglg9mABMAFASkQbwFCL4gGwFMpEBDALkTBAFsAjIgJ0QB9qQCDEBeDrgNzZc+KEwCeWEfnxleiAIwAmAMxCZMpiRBMkZdfgC+0xBDJQIAC0QoiGHBtGWmcAO6IiAxCeMzgMMDIuSRwTGQgEAGc4YgA6AjgAcxQyNANHGGAbOQBCPhouRAAyIvJYqDgAMRgADyIAExQABgwePgAiZRV2+zDHb37EXyNsY2xUNKA

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