fix(REPL): using/import statements should on top-level, #49041 (#49098)

Author: wangl-cc

stdlib/REPL/src/REPL.jl

@@ -1407,12 +1407,24 @@ function repl_eval_counter(hp)
 end
 
 function out_transform(@nospecialize(x), n::Ref{Int})
-    return quote
+    return Expr(:toplevel, get_usings!([], x)..., quote
         let __temp_val_a72df459 = $x
             $capture_result($n, __temp_val_a72df459)
             __temp_val_a72df459
         end
+    end)
+end
+
+function get_usings!(usings, ex)
+    # get all `using` and `import` statements which are at the top level
+    for (i, arg) in enumerate(ex.args)
+        if Base.isexpr(arg, :toplevel)
+            get_usings!(usings, arg)
+        elseif Base.isexpr(arg, [:using, :import])
+            push!(usings, popat!(ex.args, i))
+        end
     end
+    return usings
 end
 
 function capture_result(n::Ref{Int}, @nospecialize(x))

stdlib/REPL/test/repl.jl

@@ -1647,6 +1647,11 @@ fake_repl() do stdin_write, stdout_read, repl
     s = sendrepl2("x_47878 = range(-1; stop = 1)\n", "-1:1")
     @test contains(s, "Out[11]: -1:1")
 
+    # Test for https://github.com/JuliaLang/julia/issues/49041
+    s = sendrepl2("using Test; @test true", "In [14]")
+    @test !contains(s, "ERROR")
+    @test contains(s, "Test Passed")
+
     write(stdin_write, '\x04')
     Base.wait(repltask)
 end