ladybird/Userland/Libraries/LibJS/Tests/async-this-value.js at 6becd13a83a910047a25a980f70fbee8498a44f5 - mirrors/ladybird - git.jellysandwich.dev

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Andreas Kling a91bb72dab LibJS: Don't overwrite cached this value on async/generator reentry

When resuming execution of a suspended function, we must not overwrite
any cached `this` value with something from the ExecutionContext.

This was causing an empty JS::Value to leak into the VM when resuming
an async arrow function, since the "this mode" for such functions is
lexical and thus ExecutionContext will have an empty `this`.

It became a problem due to the bytecode optimization where we allow
ourselves to assume that `this` remains cached after we've executed a
ResolveThisBinding in this (or the first) basic block of the executable.

Fixes https://github.com/LadybirdBrowser/ladybird/issues/138

2024-06-20 10:17:18 +02:00

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 test("this value in async function", () => {
     function X() {
         this.boog = async () => {
             this.f = await null;
         };
     }
     new X().boog();
 });