consider using LiteralPropertyName instead of PropertyName

[michaelficarra]

You certainly would not want the name to be evaluated and potentially different for each instance. If the name is only evaluated once, that is a strange inconsistency between how the left and right expressions are evaluated. Additionally, properties like [a] = [0] really look like destructuring bindings, which would be confusing for readers.

[jeffmo]

We need to retain computed property names for purposes of things like symbol-named properties (at least):

var stuff = Symbol("stuff");
class Foo {
  [stuff] = 42;
}

On the syntax looking like an assignment front: I think this confusion has come up in a few other places and as a result I've been toying with a few options. Perhaps a special field-initializer operator such as =: or maybe even <- would help make it clear that these initializations are not assignments in the normal sense.

[jeffmo]

=: could get a little funky looking with type annotations:

class Foo {
  foo:number =: 42
}

<- is pretty pleasant, though:

class Foo {
  foo:number <- 42
}

[michaelficarra]

I initially was thinking : for consistency with object properties, but that would get in the way of your type annotations if both are optional. Sticking with = is fine, since it is consistent with destructuring/parameter defaults, an even more related concept. Still, I wish there was a way to support the symbol use case without allowing arbitrary expressions. Please ensure the semantics are defined in a way that evaluates the property name only once.