diff --git a/stdlib/REPL/src/REPLCompletions.jl b/stdlib/REPL/src/REPLCompletions.jl
index fc84bd2b8d3b2..5cd1e5b310087 100644
--- a/stdlib/REPL/src/REPLCompletions.jl
+++ b/stdlib/REPL/src/REPLCompletions.jl
@@ -527,7 +527,7 @@ function dict_identifier_key(str,tag)
         # Avoid `isdefined(::Array, ::Symbol)`
         isa(obj, Array) && return (nothing, nothing, nothing)
     end
-    begin_of_key = first(findnext(r"\S", str, nextind(str, end_of_identifier) + 1)) # 1 for [
+    begin_of_key = first(something(findnext(r"\S", str, nextind(str, end_of_identifier) + 1), 1)) # 1 for [
     begin_of_key==0 && return (true, nothing, nothing)
     partial_key = str[begin_of_key:end]
     (isa(obj, AbstractDict) && length(obj) < 1e6) || return (true, nothing, nothing)
diff --git a/stdlib/REPL/test/replcompletions.jl b/stdlib/REPL/test/replcompletions.jl
index accd6b8107295..8187150114c7a 100644
--- a/stdlib/REPL/test/replcompletions.jl
+++ b/stdlib/REPL/test/replcompletions.jl
@@ -905,6 +905,9 @@ function test_dict_completion(dict_name)
     s = "$dict_name[:α"
     c, r = test_complete(s)
     @test c == Any[":α]"]
+    s = "$dict_name["
+    c, r = test_complete(s)
+    @test !isempty(c)
 end
 test_dict_completion("CompletionFoo.test_dict")
 test_dict_completion("CompletionFoo.test_customdict")