Specification for Enum's needs to use 'SignedInteger' in constant productions, not NumericLiteral

[mhegazy]

Courtsey of @CyrusNajmabadi

The spec currently lists this in the grammar productions for an Enum:

ConstantEnumMemberSection:
PropertyName = NumericLiteral
PropertyName = NumericLiteral , ConstantEnumMembers

This is slightly incorrect (and different from a previous version of the spec).

Specifically, previous versions used:

PropertyName = SignedInteger

The approach with "SignedInteger" is likely more correct. NumericLiteral doesn't allow for things like "-1". With the grammar productions as they exist in the latest version of the spec "-1" would be thought of as a computed expression. i.e. the negation expression of the literal '1'.

This is important if we consider "-1" as a constant or not in an enum. Right now we do. But according to the spec, it would not be.

Also, with "PropertyName = NumericLiteral" we can do "Foo = 3.14159" and that would be considered a constant. That's likely not at all what we want

[jbondc]

I'm confused by this, is it a breaking change? Prefer NumericLiteral... that's more closely aligned with JavaScript / Number.

A signedInteger enum should be declared as ~:

enum<int32> a {
  a, // 0
  b, = 1.1 // error, initializer must be a constant expression of type 'int32'
  c, = -1, // ok
  d, // 1
}

[ahejlsberg]

No longer an issue. Closing.