IdentifierStart cannot occur following a NumericLiteral

[DanielRosenwasser]

From 11.8.3 - NumericLiterals:

The SourceCharacter immediately following a NumericLiteral must not be an IdentifierStart or DecimalDigit.

NOTE For example:

3in

is an error and not the two input elements 3 and in.

So the following should be an error:

let hasFour = 3in[null, null, null, null];