diff --git a/src/parser/parser.rs b/src/parser/parser.rs
index 9fdaa4eff2c..fb43923f8c5 100644
--- a/src/parser/parser.rs
+++ b/src/parser/parser.rs
@@ -778,7 +778,7 @@ impl<'cmd> Parser<'cmd> {
                     "Parser::parse_long_arg({:?}): Got invalid literal `{:?}`",
                     long_arg, rest
                 );
-                let used: Vec<Id> = matcher
+                let mut used: Vec<Id> = matcher
                     .arg_ids()
                     .filter(|arg_id| {
                         matcher.check_explicit(arg_id, &crate::builder::ArgPredicate::IsPresent)
@@ -790,6 +790,7 @@ impl<'cmd> Parser<'cmd> {
                     })
                     .cloned()
                     .collect();
+                used.push(arg.get_id().clone());
 
                 Ok(ParseResult::UnneededAttachedValue {
                     rest: rest.to_str_lossy().into_owned(),
diff --git a/tests/builder/flags.rs b/tests/builder/flags.rs
index 83d2464b681..50ba789a4f3 100644
--- a/tests/builder/flags.rs
+++ b/tests/builder/flags.rs
@@ -142,7 +142,7 @@ fn unexpected_value_error() {
     const USE_FLAG_AS_ARGUMENT: &str = "\
 error: The value 'foo' was provided to '--a-flag' but it wasn't expecting any more values
 
-Usage: mycat [OPTIONS] [filename]
+Usage: mycat --a-flag [filename]
 
 For more information try '--help'
 ";