@@ -0,0 +1,1229 @@
+package picocli;%0A%0Aimport org.junit.Rule;%0Aimport org.junit.Test;%0Aimport org.junit.contrib.java.lang.system.SystemErrRule;%0Aimport picocli.CommandLine.Command;%0A%0Aimport static org.junit.Assert.*;%0A%0Apublic class Issue1537Ambiguous %7B%0A%0A    @Rule%0A    public SystemErrRule systemErrRule = new SystemErrRule().enableLog().muteForSuccessfulTests();%0A%0A    @Command%0A    static class MyCommand implements Runnable %7B%0A%0A        @Command(name = %22chemical-files%22, aliases = %22chem-formats%22)%0A        void sub() %7B%7D%0A%0A        public void run() %7B%7D%0A    %7D%0A%0A    @Test%0A    public void testExecute() %7B%0A        int exitCode = new CommandLine(new MyCommand()).execute(%22chem%22);%0A        assertEquals(2, exitCode);%0A%0A        String expected = String.format(%0A            %22Unmatched argument at index 0: 'chem'%25n%22 +%0A            %22Did you mean: chem-formats or chemical-files?%25n%22);%0A        assertEquals(expected, systemErrRule.getLog());%0A    %7D%0A%0A    @Test%0A    public void testParseArgs() %7B%0A        try %7B%0A            new CommandLine(new MyCommand()).parseArgs(%22chem%22);%0A            fail(%22expected exception%22);%0A        %7D catch (CommandLine.UnmatchedArgumentException ex) %7B%0A            assertEquals(%22Unmatched argument at index 0: 'chem'%22, ex.getMessage());%0A        %7D%0A    %7D%0A%7D%0A

add test (cannot reproduce)