E4176

Compiler diagnostic name: invalid_lexmatch_target.

Invalid lexmatch target.

lexmatch works on textual views. The target expression must have a type that can be matched by regex patterns, such as String or StringView, instead of a numeric, boolean, or other unrelated type.

Erroneous example

///|
pub fn match_number(n : Int) -> Unit {
  lexmatch n with longest {
    _ => ()
  }
}

The target is an Int, which cannot be consumed by lexmatch.

Suggestion

Match a string-like value, or convert the input before using lexmatch.

///|
pub fn match_text(text : String) -> Unit {
  lexmatch text with longest {
    _ => ()
  }
}