Should matching construct be a primary expression?

[JLHwung]

The readme mentions that

The pattern matching construct should be usable as an expression:

return match { … }
let foo = match { … }
() => match { … }

Based on the examples, I assume match () {} is a PrimaryExpression, which, if so, will align to other similar structs introduced in proposals like do-expressions and module blocks.

Being a primary expression means that besides the examples mentioned above, the following codes are also valid, I don't see a strong reason to disallow them.

match (res) { when (200) { res } }.code // match can start a member chain without parenthesis
match (res) { when (200) { res } } + 1 // match can be in BinaryExpression without parenthesis

We will then need to modify AssignmentTargetType to disallow match in LHS:

match (res) { when (200) { res } } = 1
match (res) { when (200) { res } } += 1

[ljharb]

I agree that both of the first two should be valid, and the last two should not be.

[mpcsh]

I've captured this information and will merge it into the repo for future reference.