unhelpful error message on invalid bytes inside multi line string literal

[Techatrix]

Zig Version

0.14.0-dev.764+eb1a199df

Steps to Reproduce and Observed Output

// example.zig
const foo =
    \\const S = struct {
    \\<TAB>// hello
    \\}
;

Running zig fmt --check example.zig outputs:

example.zig:3:1: error: expected ';' after declaration
    \\ // hello
^

This message had me so confused that I though that there was a bug in the parser or tokenizer. Luckily it was just #20885 rejecting tabs inside multiline string literals.

Expected Output

I would expect an error message that does fulfills these requirements:

• mention that invalid bytes have been encountered
• mention where the invalid byte is located
• mention the value of the byte

Something like this:

:3:6: error: found 'invalid bytes' inside multiline string literals
:3:6: note: invalid byte: '\\x09'

[jiacai2050]

This bug also bite me, does this mean we are not allowed to use tab in multi line string?

[Vexu]

does this mean we are not allowed to use tab in multi line string?

Yes, see ziglang/zig-spec#38 for details.

[jayschwa]

The unhelpful error also occurs when a comment has an invalid byte.

[sweetbbak]

I just spent longer than I want to admit tracking down a bug that ended up being a tab in a comment... I feel like this is an error that zig fmt could have easily fixed, but it currently doesn't.