[REPLCompletions] allow symbol completions within incomplete macrocal…

…l expression

fix #51827

stdlib/REPL/src/REPLCompletions.jl

@@ -1053,6 +1053,11 @@ function complete_identifiers!(suggestions::Vector{Completion}, @nospecialize(ff
  if isinfix
  ex = ex.args[end]
  end
+ elseif isexpr(ex, :macrocall) && length(ex.args) > 1
+ # allow symbol completions within potentially incomplete macrocalls
+ if s[end] ≠ '`' && s[end] ≠ ')'
+ ex = ex.args[end]
+ end
  end
  end
  append!(suggestions, complete_symbol(ex, name, ffunc, context_module))

stdlib/REPL/test/replcompletions.jl

@@ -2085,6 +2085,18 @@ for (s, compl) in (("2*CompletionFoo.nam", "named"),
  @test only(c) == compl
 end
 
+# allows symbol completion within incomplete :macrocall
+# https://github.com/JuliaLang/julia/issues/51827
+macro issue51827(args...)
+ length(args) ≥ 2 || error("@issue51827: incomplete arguments")
+ return args
+end
+let s = "@issue51827 Base.ac"
+ c, r, res = test_complete_context(s)
+ @test res
+ "aquire" in c
+end
+
 let t = REPLCompletions.repl_eval_ex(:(`a b`), @__MODULE__; limit_aggressive_inference=true)
  @test t isa Core.Const
  @test t.val == `a b`