local variable is never mutated

[shiena]

Since zig 0.12.0 there are several codes that give the local variable is never mutated error. For example

https://github.com/Sobeston/zig.guide/blob/master/website/versioned_docs/version-0.12/01-language-basics/23-optionals.md

test "orelse" {
    var a: ?f32 = null;
    var b = a orelse 0;
    try expect(b == 0);
    try expect(@TypeOf(b) == f32);
}

But don't worry. This can be avoided by using a code like _ = &a; as described by the PRs author. https://github.com/ziglang/zig/pull/18017

test "orelse" {
    var a: ?f32 = null;
    var b = a orelse 0;
    try expect(b == 0);
    try expect(@TypeOf(b) == f32);
    _ = &a;
    _ = &b;
}

[Sobeston]

Fixed this one in https://github.com/Sobeston/zig.guide/commit/51f80b5fc8f25aec2a470109ee3826ce1d8281da Thanks for the report, trying to fix the others now

[shiena]

@Sobeston Thanks for the correction. The following other code also causes the same compile error.

https://github.com/Sobeston/zig.guide/blob/master/website/versioned_docs/version-0.12/01-language-basics/24-comptime.md

• comptime blocks / x, y

https://github.com/Sobeston/zig.guide/blob/master/website/versioned_docs/version-0.12/01-language-basics/25-payload-captures.md

• optional-if / maybe_num
• error union if / ent_num
• switch capture / b

https://github.com/Sobeston/zig.guide/blob/master/website/versioned_docs/version-0.12/01-language-basics/28-anonymous-structs.md

• anonymous struct literal / pt

https://github.com/Sobeston/zig.guide/blob/master/website/versioned_docs/version-0.12/01-language-basics/29-sentinel-termination.md

• coercion / a, c, e

https://github.com/Sobeston/zig.guide/blob/master/website/versioned_docs/version-0.12/01-language-basics/30-vectors.md

• vector looping / sum

[Sobeston]

Thanks again for the detailed report! Fixed in:

• ad3804d80f99448a2801d4cb641d025269a13f7f
• 2e34474beec5b25058fa7715b36e5b329c650b75
• 21c6b61f291a6f06e60a5c41a157827deef0dcff
• 6d9c323a4da9c481c4cc0176f0d8849e7058b8d5
• e82c212677b84ff8d2f3021afa2771deecece204