MethodError: no method matching is_syntactic_operator

[antimon2]

In Julia1.6-beta1, the following error occurs if showing an Expr containing macro calls with symbolic characters.

julia-1.6.0-beta1> :(@..{1,2,..})
:(#= REPL[1]:1 =# @Error showing value of type Expr:
ERROR: MethodError: no method matching is_syntactic_operator(::String)
Closest candidates are:
  is_syntactic_operator(::Symbol) at show.jl:1221
Stacktrace:
  [1] is_valid_identifier
    @ ./show.jl:1399 [inlined]
  [2] show_sym(io::IOContext{Base.TTY}, sym::String; allow_macroname::Bool)
    @ Base ./show.jl:1438
  [3] show_sym
    @ ./show.jl:1438 [inlined]
  [4] show_sym(io::IOContext{Base.TTY}, sym::Symbol; allow_macroname::Bool)
    @ Base ./show.jl:1442
  [5] show_unquoted(io::IOContext{Base.TTY}, ex::Expr, indent::Int64, prec::Int64, quote_level::Int64)
    @ Base ./show.jl:1942
  [6] show_list(io::IOContext{Base.TTY}, items::Vector{Any}, sep::Char, indent::Int64, prec::Int64, quote_level::Int64, enclose_operators::Bool, kw::Bool)
    @ Base ./show.jl:1385
  [7] show_list
    @ ./show.jl:1366 [inlined]
  [8] show_unquoted(io::IOContext{Base.TTY}, ex::Expr, indent::Int64, prec::Int64, quote_level::Int64)
    @ Base ./show.jl:1935
  [9] show_unquoted_quote_expr(io::IOContext{Base.TTY}, value::Any, indent::Int64, prec::Int64, quote_level::Int64)
    @ Base ./show.jl:1515
 [10] show
    @ ./show.jl:1134 [inlined]
 [11] show(io::IOContext{Base.TTY}, #unused#::MIME{Symbol("text/plain")}, x::Expr)
    @ Base.Multimedia ./multimedia.jl:47
 [12] (::REPL.var"#38#39"{REPL.REPLDisplay{REPL.LineEditREPL}, MIME{Symbol("text/plain")}, Base.RefValue{Any}})(io::Any)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:220
 [13] with_repl_linfo(f::Any, repl::REPL.LineEditREPL)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:462
 [14] display(d::REPL.REPLDisplay, mime::MIME{Symbol("text/plain")}, x::Any)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:213
 [15] display(d::REPL.REPLDisplay, x::Any)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:225
 [16] display(x::Any)
    @ Base.Multimedia ./multimedia.jl:328
 [17] #invokelatest#2
    @ ./essentials.jl:707 [inlined]
 [18] invokelatest
    @ ./essentials.jl:706 [inlined]
 [19] print_response(errio::IO, response::Any, show_value::Bool, have_color::Bool, specialdisplay::Union{Nothing, AbstractDisplay})
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:247
 [20] (::REPL.var"#40#41"{REPL.LineEditREPL, Pair{Any, Bool}, Bool, Bool})(io::Any)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:231
 [21] with_repl_linfo(f::Any, repl::REPL.LineEditREPL)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:462
 [22] print_response(repl::REPL.AbstractREPL, response::Any, show_value::Bool, have_color::Bool)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:229
 [23] (::REPL.var"#do_respond#61"{Bool, Bool, REPL.var"#72#82"{REPL.LineEditREPL, REPL.REPLHistoryProvider}, REPL.LineEditREPL, REPL.LineEdit.Prompt})(s::REPL.LineEdit.MIState, buf::Any, ok::Bool)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:798
 [24] #invokelatest#2
    @ ./essentials.jl:707 [inlined]
 [25] invokelatest
    @ ./essentials.jl:706 [inlined]
 [26] run_interface(terminal::REPL.Terminals.TextTerminal, m::REPL.LineEdit.ModalInterface, s::REPL.LineEdit.MIState)
    @ REPL.LineEdit /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/LineEdit.jl:2441
 [27] run_frontend(repl::REPL.LineEditREPL, backend::REPL.REPLBackendRef)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:1126
 [28] (::REPL.var"#44#49"{REPL.LineEditREPL, REPL.REPLBackendRef})()
    @ REPL ./task.jl:406

As a comment on #38830 I reported, I see that applying a patch merged into master solves this problem.

(↓ with my local build)

julia-1.6.0-DEV.1780> :(@..{1,2,..})
:(#= REPL[1]:1 =# @.. {1, 2, ..})

(the above is same behavior in Julia v1.5.x and v1.7-DEV).

[antimon2]

Close this issue because of PR #39160 merged into release-1.6 branch.
It seems to be incorporated when beta2 or rc1 is released.
I have confirmed the behavior with my local build.

julia-1.6.0-beta1.81> :(@..{1,2,..})
:(#= REPL[1]:1 =# @.. {1, 2, ..})