Simplify calling of the suggestion function.

args.go

@@ -33,7 +33,7 @@ func legacyArgs(cmd *Command, args []string) error {
 
 	// root command with subcommands, do subcommand checking.
 	if !cmd.HasParent() && len(args) > 0 {
-		return fmt.Errorf("unknown command %q for %q%s", args[0], cmd.CommandPath(), cmd.SuggestFunc()(args[0]))
+		return fmt.Errorf("unknown command %q for %q%s", args[0], cmd.CommandPath(), cmd.SuggestFunc(args[0]))
 	}
 	return nil
 }
@@ -58,7 +58,7 @@ func OnlyValidArgs(cmd *Command, args []string) error {
 		}
 		for _, v := range args {
 			if !stringInSlice(v, validArgs) {
-				return fmt.Errorf("invalid argument %q for %q%s", v, cmd.CommandPath(), cmd.SuggestFunc()(args[0]))
+				return fmt.Errorf("invalid argument %q for %q%s", v, cmd.CommandPath(), cmd.SuggestFunc(args[0]))
 			}
 		}
 	}

command.go

@@ -483,16 +483,16 @@ func (c *Command) Help() error {
 	return nil
 }
 
-// SuggestFunc returns either the function set by SetSuggestFunc for this command
-// or a parent, or it returns a function with default suggestion behavior.
-func (c *Command) SuggestFunc() func(string) string {
+// SuggestFunc returns suggestions for the provided typedName using either
+// the function set by SetSuggestFunc for this command, parent's or a default one.
+func (c *Command) SuggestFunc(typedName string) string {
 	if c.suggestFunc != nil && !c.DisableSuggestions {
-		return c.suggestFunc
+		return c.suggestFunc(typedName)
 	}
 	if c.HasParent() {
-		return c.Parent().SuggestFunc()
+		return c.Parent().SuggestFunc(typedName)
 	}
-	return c.findSuggestions
+	return c.findSuggestions(typedName)
 }
 
 // UsageString returns usage string.