RFC 3101 (rust-lang/rfcs#3101) reserves lexical forms like the following:
ident#fooident"foo"ident'f'ident#123
This isn't covered in the FLS.
They're reserved in the 2021 edition and later, and the FLS currently describes the 2021 edition.
rust-lang/rust#126452 extended the RFC to reserving forms like
Here, "reserves" means that it's a lexing-time error if any of those forms appear.
These are covered in the Reference under lex.token.reserved-prefix. That models them as separate forms of token, using grammar productions which don't overlap with the productions for accepted tokens.
There is some discussion of this approach in rust-lang/reference#1128.
RFC 3101 (rust-lang/rfcs#3101) reserves lexical forms like the following:
ident#fooident"foo"ident'f'ident#123This isn't covered in the FLS.
They're reserved in the 2021 edition and later, and the FLS currently describes the 2021 edition.
rust-lang/rust#126452 extended the RFC to reserving forms like
'ident#fooHere, "reserves" means that it's a lexing-time error if any of those forms appear.
These are covered in the Reference under
lex.token.reserved-prefix. That models them as separate forms of token, using grammar productions which don't overlap with the productions for accepted tokens.There is some discussion of this approach in rust-lang/reference#1128.