Related versions: Babel 7.13.9 V8 9.1.216

await as BindingIdentifier of FunctionDeclaration

C = class { static { function await() {} } };

Babel throws, V8 passes.

According to #27 (comment), a function boundary includes parameters and body. So the binding identifier await should throw here.

await as IdentifierReference in ConciseBody of ArrowFunctionExpression

C = class { static { () => await } };

Babel throws, V8 passes.

C = class { static { () => arguments } }

Babel throws, V8 throws.

In the spec we have same treatment for IdentifierReference when its SV is arguments or await, so they should either both throw or both pass. I am not clear whether function boundary includes an arrow function. But since this already throw

C = class { static p = () => arguments }

I am good to throw for C = class { static { () => arguments } }.

I don't have strong opinion for C = class { static { () => await } };, I tend to forbid it even though we allow C = class { static p = () => await }.

/cc @syg since you implemented static block features.