[JuliaLowering] Refactor function desugaring (#61342)
A number of fixes that hopefully make up for the large diff. Currently
atop https://github.com/JuliaLang/julia/pull/61213
Changes:
1. Handle destructuring (tuple) params first, like flisp does, since
it's
simpler to assume every param is a single identifier later.
2. Structure "expand function", "method-def-expr",
"keyword-method-def-expr",
and "optional positional wrappers" to call each other like flisp does. I
think it's simpler this way, and it also affects the order of the
methods
(closure boxes unfortunately depend on this right now; see discussion in
#61051).
3. Don't rewrite constructors with callbacks passed to
expand_function_def. I
think this was originally since matching the function name was too
messy, but
validation.jl and pattern-matching make this doable (even flisp uses its
own
pattern-lambda language here)
4. Keep args bundled with their types for longer
5. Keep typevars bundled with their bounds for longer with new
`K"_typevar"`
(flisp does this with 3-long lists).
6. Set the first argument to `:method` expressions to `nothing` if the
function
is local. I think flisp does this to remove unnecessary data
dependencies.
7. Add `valid_st2` (just for internal use).
8. Push the generated function wrapper (previously `generated_function`,
now
`_generated_body`) down to wrap the body of the function instead, and
introduce it in `est_to_dst` instead of macro expansion. That
information
needs to travel with the function body anyway to get to the right
`method_def_expr` calls.
Fixes:
- fix https://github.com/JuliaLang/JuliaLowering.jl/issues/158, failure
to
detect inter-arg static param dependencies. As discussed with
@topolarity,
we're trying out something slightly different from flisp commented on in
`optional_positional_defs`
- fix https://github.com/JuliaLang/JuliaLowering.jl/issues/157.
- fix https://github.com/JuliaLang/JuliaLowering.jl/issues/156.
Destructuring
args are now treated the same in function-name position.
- fix https://github.com/JuliaLang/JuliaLowering.jl/issues/155, unused
args not
marked unused. This is part of function desugaring in flisp and I've
tried to
match that logic within the JL framework. This means
`Symbol("#unused#")`
becomes `K"Placeholder"` in `est_to_dst`, the reverse happens in
`to_lowered_expr`, and generated functions do their own detection for
the
quoted arglist.
- Initial support for method table overlays
- fix and test anonymous generated functions
https://github.com/JuliaLang/JuliaLowering.jl/issues/152 is also worth
checking
TODO (later):
- Support globalref properly (validator and existing lowering recognize
it, but
it isn't generally expected as an lvalue in desugaring)
- Overlays need more work
- Destructured args in generated functions may need to be special-cased,
since
desugaring pushes statements into the body
- Fix `where` expression in function name
(https://github.com/JuliaLang/julia/pull/35861). This PR fixes the
desugaring
part, but scope resolution appears to fail.
---------
Co-authored-by: Cody Tapscott <topolarity@tapscott.me>
