- introduce the concept of qualifiers on l-value types
- teach overload resolution and coercion how to drop explicitness
- require explicitness on normal [byref] arguments
- make 'this' [byref(implicit)]
- special-case '&' as a unary operator in the parser to make it
produce an expression which type-checks as turning implicit l-values
into explicit ones.
Obvious missing pieces:
- updating LangRef
- we should really complain about ever trying to rvalue-convert an
explicit l-value
- maybe qualification should play a part in overload resolution
- we should diagnose attempts to declare unary '&' operators
- there's a test case in expressions.swift which suggests my logic is
slightly off
But I am out of time, and these will have to wait.
Swift SVN r1119
inconsistent (so it needs to be killed) but that we want to retain source
range information and not kill the entire subtree that contains it.
Swift SVN r1073
a tuple with one element and no labels. This form is
treated specially in essentially every case, so it might
as well be its own expression kind.
Swift SVN r1021
