E0076

Warning name: lexmatch_first_match

This warning described an earlier experimental form of first-match lexmatch and is not emitted by the current compiler.

Current lexmatch expressions use re"..." case patterns and may use the default first-match strategy. For a single boolean check, a regex match expression is usually more concise.

Erroneous example

///|
fn classify(input : String) -> String {
  lexmatch input {
    "if" => "keyword"
    _ => "other"
  }
}

///|
test {
  ignore(classify)
}

Suggestion

Rewrite the old string-piece pattern syntax with re"..." cases, or use a regex match expression when only a boolean result is needed.

///|
fn classify(input : String) -> String {
  if input =~ re"^if$" {
    "keyword"
  } else {
    "other"
  }
}

///|
test {
  ignore(classify)
}