stage2 astgen: catch unused vars

[g-w1]

I am almost positive the actual impl works (besides a preexisting TODO in asm which I will fix, and maybe some other bugs like the struct type not getting referenced), the main work is just fixing all the code which will take a bunch of work.

If you see your code is in some of the unused vars (either in the code or ci failure), it would help me a lot if you could tell me the correct way to do it as I may not know.

Issues to file:

                            return astgen.failNodeNotes(ident, "'{s}' not accessible from inner function", .{ident_name}, &.{
                                try astgen.errNoteTok(local_ptr.token_src, "declared here", .{}),
                                // TODO add crossed function definition here note.
                                // Maybe add a note to the error about it being because of the var,
                                // maybe recommend copying it into a const variable. -SpexGuy

[Vexu]

Could you add the is_inline change from #8921 (comment) here?

[g-w1]

Oops, did not see that, I will.

[LemonBoy]

The two occurrences in lib/std/compress/* can be safely removed.
cc @jedisct1 for the crypto stuff.

Shall we add some kind of escape hatch for this? Many languages exclude from this rule variables whose name starts with an underscore.

[g-w1]

#335 (comment) should work to disable them.

[LemonBoy]

#335 (comment) should work to disable them.

Fair enough, it's a bit verbose but works without adding extra logic that's dependent on the variable's name. I like it.

[g-w1]

Last few vars:

math/complex/ldexp.zig:56:11: error: unused local constant
    const kln2 = 1246.97177782734161156; // k * ln2
          ^
hash/wyhash.zig:169:15: error: unused local constant
        const seed = self.state.seed;
              ^
os/linux/io_uring.zig:1280:11: error: unused local constant
    const connect = try ring.connect(0xcccccccc, client, &address.any, address.getOsSockLen());
          ^
crypto/bcrypt.zig:51:13: error: unused local variable
        var t: u32 = undefined;
            ^
crypto/bcrypt.zig:78:13: error: unused local variable
        var t: u32 = undefined;
            ^
crypto/aes/soft.zig:52:15: error: unused local constant
        const src = &block.repr;
              ^
crypto/aes/soft.zig:69:15: error: unused local constant
        const src = &block.repr;
              ^
crypto/aes/soft.zig:91:15: error: unused local constant
        const src = &block.repr;
              ^
crypto/aes/soft.zig:108:15: error: unused local constant
        const src = &block.repr;
              ^
crypto/25519/scalar.zig:339:15: error: unused local constant
        const t23 = @truncate(u64, z32 + c21) & 0xffffffffffffff;
              ^
crypto/25519/scalar.zig:614:15: error: unused local constant
        const t102 = @as(u64, @truncate(u64, z31 + c20)) & 0xffffffffffffff;
              ^
crypto/chacha20.zig:447:25: error: unused local variable
                    var i: u32 = 0;
                        ^

[LemonBoy]

This change surfaced a lot of big and small problems in the stdlib, awesome.
Fixing all the problems is probably better if done in a separate PR.

[LemonBoy]

@hoanga Please introduce the B_* constants for error codes. Returning 1 here is a safe default but I think errors should be bubbled up to the caller.
Speaking of get_system_info, this line looks wrong, they probably meant return error.

const count: u32 = if (os.system.get_system_info(&system_info) != 0)
    system_info.cpu_count
else
    1;

[jedisct1]

Last few vars:

crypto/bcrypt.zig:51:13: error: unused local variable
        var t: u32 = undefined;
            ^
crypto/bcrypt.zig:78:13: error: unused local variable
        var t: u32 = undefined;
            ^
crypto/aes/soft.zig:52:15: error: unused local constant
        const src = &block.repr;
              ^
crypto/aes/soft.zig:69:15: error: unused local constant
        const src = &block.repr;
              ^
crypto/aes/soft.zig:91:15: error: unused local constant
        const src = &block.repr;
              ^
crypto/aes/soft.zig:108:15: error: unused local constant
        const src = &block.repr;
              ^
crypto/25519/scalar.zig:339:15: error: unused local constant
        const t23 = @truncate(u64, z32 + c21) & 0xffffffffffffff;
              ^
crypto/25519/scalar.zig:614:15: error: unused local constant
        const t102 = @as(u64, @truncate(u64, z31 + c20)) & 0xffffffffffffff;
              ^
crypto/chacha20.zig:447:25: error: unused local variable
                    var i: u32 = 0;
                        ^

Fine to remove them all.

[jedisct1]

This is turning into an epic PR! 👍