Pattern matching for chars are broken

[amiralies]

let isA = c =>
  switch c {
  | 'a' => true
  }

produces this

// Generated by ReScript, PLEASE EDIT WITH CARE
'use strict';


function isA(c) {
  return true;
}

exports.isA = isA;
/* No side effect */

without warnigs.

[cristianoc]

Indeed thanks for reporting. Moving to the syntax repo.

[IwanKaramazow]

What makes this a syntax problem? Is this also unicode related?

[cristianoc]

No quotes are added in the generated code.

[cristianoc]

Which means it's probably a compiler problem.
And might need to transfer this back.

[cristianoc]

Not sure what the issue is. The generated code looks file.
Please reopen with an example that illustrates the issue.

[amiralies]

The above isA function is certainly includes a partial matching.
It should return true when the input is 'a' and throw Match_failure on other inputs.
The generated code for that block is something like this in 9.1.4

function isA(c) {
  if (c === 97) {
    return true;
  }
  throw {
        RE_EXN_ID: "Match_failure",
        _1: [
          "Main.res",
          2,
          2
        ],
        Error: new Error()
      };
}

[cristianoc]

Got it.
Have you observed anything except char? Is that the only type leading to this issue?

[cristianoc]

So the No side effect seems like the clue. Perhaps the code is transformed before it even reached the type checker, which would definitely complain.

[cristianoc]

It seems to be only for chars, e.g. not strings or integers. That's peculiar.

[amiralies]

Got it. Have you observed anything except char? Is that the only type leading to this issue?

Didn't see this happening with other types. just char and char interval (which is the same from typechecker pov)