Remove a?.b = c and delete a?.b

[claudepache]

Those are merely by-products of the spec mechanics (Nil reference), rather the intended semantics of optional chaining.

The proposed semantics may also be somewhat confusing for users, and it makes more difficult to have simple understanding of what short-circuiting does.

Those could be re-added later in case clear semantics and compelling use cases are found.

Strategy for fixing the issue:

• use proper grammar and/or use static semantics in order to have SyntaxError where possible;
• PutValue on a Nil Reference should throw a TypeError. Ditto for the delete operator.

[claudepache]

I have kept delete a?.b because:

• it has a reasonable use case, Should delete a?.b be allowed or forbidden? tc39/proposal-optional-chaining#14 (comment);
• it could hardly be confusing;
• it is consistent with delete a.b not throwing when a evaluates to a primitive value different from null/undefined.