fix Dict completion when using non-ASCII (fix JuliaLang#23004)

base/repl/REPLCompletions.jl

@@ -407,18 +407,18 @@ function dict_identifier_key(str,tag)
  str_close = str
  end
 
- frange, end_of_indentifier = find_start_brace(str_close, c_start='[', c_end=']')
+ frange, end_of_identifier = find_start_brace(str_close, c_start='[', c_end=']')
  isempty(frange) && return (nothing, nothing, nothing)
  obj = Main
- for name in split(str[frange[1]:end_of_indentifier], '.')
+ for name in split(str[frange[1]:end_of_identifier], '.')
  Base.isidentifier(name) || return (nothing, nothing, nothing)
  sym = Symbol(name)
  isdefined(obj, sym) || return (nothing, nothing, nothing)
  obj = getfield(obj, sym)
  # Avoid `isdefined(::Array, ::Symbol)`
  isa(obj, Array) && return (nothing, nothing, nothing)
  end
- begin_of_key = findnext(x->!in(x,whitespace_chars), str, end_of_indentifier+2)
+ begin_of_key = first(search(str, r"\S", nextind(str, end_of_identifier) + 1)) # 1 for [
  begin_of_key==0 && return (true, nothing, nothing)
  partial_key = str[begin_of_key:end]
  (isa(obj, Associative) && length(obj) < 1e6) || return (true, nothing, nothing)
@@ -547,7 +547,7 @@ function completions(string, pos)
  elseif c==']'
  c_start='['; c_end=']'
  end
- frange, end_of_indentifier = find_start_brace(string[1:prevind(string, i)], c_start=c_start, c_end=c_end)
+ frange, end_of_identifier = find_start_brace(string[1:prevind(string, i)], c_start=c_start, c_end=c_end)
  startpos = start(frange)
  i = prevind(string, startpos)
  elseif c in ["\'\"\`"...]

test/replcompletions.jl

@@ -67,6 +67,7 @@ ex = quote
  end
  test_repl_comp_dict = CompletionFoo.test_dict
  test_repl_comp_customdict = CompletionFoo.test_customdict
+ test_dict_ℂ = Dict(1=>2)
 end
 ex.head = :toplevel
 eval(Main, ex)
@@ -748,3 +749,6 @@ test_dict_completion("CompletionFoo.test_dict")
 test_dict_completion("CompletionFoo.test_customdict")
 test_dict_completion("test_repl_comp_dict")
 test_dict_completion("test_repl_comp_customdict")
+
+# Issue #23004: this should not throw:
+@test REPLCompletions.dict_identifier_key("test_dict_ℂ[\\", :other) isa Tuple