Why doesn't ZLS give errors for incorrect usage of function?

Help
1

I have this minimal working example with just doing zig init and changing main.zig to this.

const std = @import("std");
const Allocator = std.mem.Allocator;

const MyType = struct {
    const Self = @This();
    pub fn init(a: Allocator, somedata: usize) Self {
        _ = a;
        _ = somedata;

        return Self{};
    }
};

pub fn main(init: std.process.Init) !void {

    // incorrect usage of MyType.init, missing arg somedata
    const my_instance = MyType.init(init.gpa);
    _ = my_instance;
}

And when I run :lua vim.diagnostic.open_float() it shows nothing, and if I press my diagnostic key <leader>X for trouble.nvim it just says no diagnostics.

Screenshot_20260614_130654
Screenshot_20260614_1306541920×1036 82.5 KB

Is my editor setup wrong or zls setup incorrect?

➜  zls_mwe  zig version
0.16.0
➜  zls_mwe  zls version
0.16.0
➜  zls_mwe  zls env
{
 "version": "0.16.0",
 "global_cache_dir": "/home/cocoa/.cache/zls",
 "global_config_dir": "/home/cocoa/.config/kdedefaults",
 "local_config_dir": "/home/cocoa/.config",
 "config_file": null,
 "log_file": "/home/cocoa/.cache/zls/zls.log"
}
2

You need to ensure zls is compiling your code, otherwise its diagnostics are very limited Build-On-Save - zigtools

You dont have to duplicate everything, that is only needed to avoid a bug in the build system that will generate and install the executable even if the installation step is never run. The custom backends, and incremental, are fast enough that it doesn’t have any impact, and the bug will be fixed in the future.

1 Like
3

Yay! tysm for the fix. One question tho, why doesn’t this also show me errors on the src/root.zig file?

//! By convention, root.zig is the root source file when making a package.
const std = @import("std");
const Io = std.Io;

pub fn f(_: usize) void {}

// calls f() incorrectly
pub fn g() void {
    return f();
}

I added the following to my build.zig

    // Step that makes zls compile check
    const check = b.step("check", "check if it compiles");
    check.dependOn(&exe.step);

    // also make it check root.zig hopefully?
    check.dependOn(&mod.step);

First part works, second part doesn’t because the module doesn’t have an associated compilation step I think?

4

That is likely because of lazy evaluation by the compiler.
Are you actually calling g anywhere?

5
  1. that file needs to be compiled, either as an import to your executable, or its own library/object which will have to be added as dependencies of your check step
  2. once it is part of the compilation, it needs to be used. Zig won’t even analyse things that are not used. The only errors you’d get for unused things are syntax errors.