fix(parser): Don't suggest -- as often

clap_builder/src/error/mod.rs

@@ -446,6 +446,7 @@ impl<F: ErrorFormatter> Error<F> {
         subcmd: String,
         did_you_mean: Vec<String>,
         name: String,
+        suggested_trailing_arg: bool,
         usage: Option<StyledStr>,
     ) -> Self {
         use std::fmt::Write as _;
@@ -456,15 +457,19 @@ impl<F: ErrorFormatter> Error<F> {
 
         #[cfg(feature = "error-context")]
         {
-            let mut styled_suggestion = StyledStr::new();
-            let _ = write!(
-                styled_suggestion,
-                "to pass '{}{subcmd}{}' as a value, use '{}{name} -- {subcmd}{}'",
-                invalid.render(),
-                invalid.render_reset(),
-                valid.render(),
-                valid.render_reset()
-            );
+            let mut suggestions = vec![];
+            if suggested_trailing_arg {
+                let mut styled_suggestion = StyledStr::new();
+                let _ = write!(
+                    styled_suggestion,
+                    "to pass '{}{subcmd}{}' as a value, use '{}{name} -- {subcmd}{}'",
+                    invalid.render(),
+                    invalid.render_reset(),
+                    valid.render(),
+                    valid.render_reset()
+                );
+                suggestions.push(styled_suggestion);
+            }
 
             err = err.extend_context_unchecked([
                 (ContextKind::InvalidSubcommand, ContextValue::String(subcmd)),
@@ -474,7 +479,7 @@ impl<F: ErrorFormatter> Error<F> {
                 ),
                 (
                     ContextKind::Suggested,
-                    ContextValue::StyledStrs(vec![styled_suggestion]),
+                    ContextValue::StyledStrs(suggestions),
                 ),
             ]);
             if let Some(usage) = usage {

clap_builder/src/parser/parser.rs

@@ -474,6 +474,10 @@ impl<'cmd> Parser<'cmd> {
             }
         }
 
+        let suggested_trailing_arg = !trailing_values
+            && self.cmd.has_positionals()
+            && (arg_os.is_long() || arg_os.is_short());
+
         if !(self.cmd.is_args_conflicts_with_subcommands_set() && valid_arg_found) {
             let candidates = suggestions::did_you_mean(
                 &arg_os.display().to_string(),
@@ -489,6 +493,7 @@ impl<'cmd> Parser<'cmd> {
                         .get_bin_name()
                         .unwrap_or_else(|| self.cmd.get_name())
                         .to_owned(),
+                    suggested_trailing_arg,
                     Usage::new(self.cmd).create_usage_with_title(&[]),
                 );
             }
@@ -505,9 +510,6 @@ impl<'cmd> Parser<'cmd> {
             }
         }
 
-        let suggested_trailing_arg = !trailing_values
-            && self.cmd.has_positionals()
-            && (arg_os.is_long() || arg_os.is_short());
         ClapError::unknown_argument(
             self.cmd,
             arg_os.display().to_string(),

tests/builder/error.rs

@@ -187,3 +187,25 @@ For more information, try '--help'.
 ";
     assert_error(err, expected_kind, MESSAGE, true);
 }
+
+#[test]
+#[cfg(feature = "error-context")]
+#[cfg(feature = "suggestions")]
+fn cant_use_trailing_subcommand() {
+    let cmd = Command::new("test").subcommand(Command::new("bar"));
+
+    let res = cmd.try_get_matches_from(["test", "baz"]);
+    assert!(res.is_err());
+    let err = res.unwrap_err();
+    let expected_kind = ErrorKind::InvalidSubcommand;
+    static MESSAGE: &str = "\
+error: unrecognized subcommand 'baz'
+
+  tip: a similar subcommand exists: 'bar'
+
+Usage: test [COMMAND]
+
+For more information, try '--help'.
+";
+    assert_error(err, expected_kind, MESSAGE, true);
+}

tests/builder/subcommands.rs

@@ -103,7 +103,6 @@ fn subcmd_did_you_mean_output() {
 error: unrecognized subcommand 'subcm'
 
   tip: a similar subcommand exists: 'subcmd'
-  tip: to pass 'subcm' as a value, use 'dym -- subcm'
 
 Usage: dym [COMMAND]
 
@@ -123,7 +122,6 @@ fn subcmd_did_you_mean_output_ambiguous() {
 error: unrecognized subcommand 'te'
 
   tip: some similar subcommands exist: 'test', 'temp'
-  tip: to pass 'te' as a value, use 'dym -- te'
 
 Usage: dym [COMMAND]
 
@@ -504,7 +502,6 @@ For more information, try 'help'.
 error: unrecognized subcommand 'baz'
 
   tip: a similar subcommand exists: 'bar'
-  tip: to pass 'baz' as a value, use ' -- baz'
 
 Usage: <COMMAND>