Before You File a Proposal Please Confirm You Have Done The Following...

• I havesearched for related issues and found none that match my proposal.
• I have searched thecurrent rule list and found no rules that match my proposal.
• I haveread the FAQ and my problem is not listed.

Relevant Package

ast-spec

My proposal is suitable for this project

• I believe my proposal would be useful to the broader TypeScript community (meaning it is not a niche proposal).

Description

classTest1{constructor(private[foo]=[1],private{ bar}={bar:1},private ...baz){}}

Currently these three parameter properties are semantic errors in TS and are similarly allowed by our parser.
However they are all non-sensical. The first twodon't even transpile to generate a property!

We should make these hard errors to block the syntax so that we can refine ourTSParameterProperty.parameter type to exclude the invalid states.

An additional case which is already a hard TS parser error that we should pre-narrow the types for -- the.left of an assignment parameter propertymust always be anIdentifier.