[REPL] Autocompletion of function arguments is broken in some cases

[giordano]

On both Julia v1.12.0-beta2 and 89003fe:

code_llvm(s<TAB>, (Float64,); debuginfo=:none)

pressing <TAB> after the s doesn't complete anything. This works as expected in Julia v1.11.

[xal-0]

Argh, this is a bad interaction between keyword argument completions and the switch to parsing the entire input: once you have the semicolon, _complete_methods returns kwargs_flag == 1, which assumes you no longer want to complete positional arguments anymore.

[xal-0]

Another bug for free, when we try to complete keyword arguments but can't evaluate the function:

julia> s = "foo(ba"; RC.completions(s, sizeof(s), Main, false, false)
ERROR: TypeError: in <:, expected Type, got a value of type Nothing
Stacktrace:
 [1] show_signature_function(io::IOBuffer, ft::Any, demangle::Bool, fargname::String, html::Bool, qualified::Bool)
   @ Base ./show.jl:2568
 [2] show_signature_function(io::IOBuffer, ft::Any)
   @ Base ./show.jl:2567
 [3] sprint(f::Function, args::Nothing; context::Nothing, sizehint::Int64)
   @ Base ./strings/io.jl:113
 [4] sprint(f::Function, args::Nothing)
   @ Base ./strings/io.jl:106
 [5] complete_methods!(out::Vector{…}, funct::Any, args_ex::Vector{…}, kwargs_ex::Set{…}, max_method_completions::Int64, exact_nargs::Bool)
   @ REPL.REPLCompletions ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.13/REPL/src/REPLCompletions.jl:835
 [6] complete_keyword_argument!(suggestions::Vector{…}, ex::Expr, last_word::String, context_module::Module; shift::Bool)
   @ REPL.REPLCompletions ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.13/REPL/src/REPLCompletions.jl:908
 [7] complete_keyword_argument!
   @ ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.13/REPL/src/REPLCompletions.jl:901 [inlined]
 [8] completions(string::String, pos::Int64, context_module::Module, shift::Bool, hint::Bool)
   @ REPL.REPLCompletions ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.13/REPL/src/REPLCompletions.jl:1099
 [9] top-level scope
   @ REPL[12]:1
Some type information was truncated. Use `show(err)` to see complete types.