Don't show default_vals in smart usage

src/parse/validator.rs

@@ -681,8 +681,11 @@ impl<'help, 'app, 'parser> Validator<'help, 'app, 'parser> {
         let used: Vec<Id> = matcher
             .arg_names()
             .filter(|n| {
+                // Filter out the args we don't want to specify.
                 self.p.app.find(n).map_or(true, |a| {
-                    !(a.is_set(ArgSettings::Hidden) || self.p.required.contains(&a.id))
+                    !a.is_set(ArgSettings::Hidden)
+                        && a.default_vals.is_empty()
+                        && !self.p.required.contains(&a.id)
                 })
             })
             .cloned()

tests/default_vals.rs

@@ -1,3 +1,4 @@
+mod utils;
 use clap::{App, Arg, ErrorKind};
 
 #[test]
@@ -588,6 +589,30 @@ fn multiple_defaults_override() {
     assert_eq!(m.values_of_lossy("files").unwrap(), vec!["other", "mine"]);
 }
 
+#[test]
+fn default_vals_donnot_show_in_smart_usage() {
+    let app = App::new("bug")
+        .arg(
+            Arg::new("foo")
+                .long("config")
+                .takes_value(true)
+                .default_value("bar"),
+        )
+        .arg(Arg::new("input").required(true));
+    assert!(utils::compare_output(
+        app,
+        "bug",
+        "error: The following required arguments were not provided:
+    <input>
+
+USAGE:
+    bug [OPTIONS] <input>
+
+For more information try --help",
+        true,
+    ));
+}
+
 #[test]
 fn issue_1050_num_vals_and_defaults() {
     let res = App::new("hello")