values of type '(enum literal)' must be comptime known

[Sobeston]

Working:

const std = @import("std");

const Mode = enum {
    Low, Medium, High, Custom
};

pub fn main() void {
    var xoroshiro = std.rand.Xoroshiro128.init(std.time.milliTimestamp());
    var random = xoroshiro.random;

    const mode: Mode = switch (random.float(f32)) {
        0.0...0.2 => .Low,
        0.2...0.4 => .Medium,
        0.4...0.6 => .High,
        0.6...1.0 => .Custom,
        else => unreachable,
    };

    std.debug.warn("{}\n", .{mode});
}

Not working:

const std = @import("std");

const Mode = enum {
    Low, Medium, High, Custom
};

pub fn main() void {
    var xoroshiro = std.rand.Xoroshiro128.init(std.time.milliTimestamp());
    var random = xoroshiro.random;

    const i: usize = 5;
    const mode: Mode = switch (i) {
        0 => .Custom,
        else => blk: {
            break :blk switch (random.float(f32)) {
                0.00...0.33 => .Low,
                0.33...0.66 => .Medium,
                0.66...1.00 => .High,
                else => unreachable
            };
        }
    };

    std.debug.warn("{}\n", .{mode});
}

Something wrong with inferring types and nested switches, maybe?

[fengb]

The type inferencer has a hard time with nested expressions:

• Peer type resolution cannot handle nested branches with a nullable struct result #3750 (comment)
• Unable to determine comptime value from if-statement inside switch #4255 (comment)

[SpexGuy]

Just confirming, this is a bug. It's fixed in stage 2.

[Sobeston]

Updating the code so that it builds with the latest version of zig

const std = @import("std");

const Mode = enum { Low, Medium, High, Custom };

pub fn main() void {
    var xoroshiro = std.rand.Xoroshiro128.init(@intCast(std.time.milliTimestamp()));
    var random = xoroshiro.random();

    const i: usize = 5;
    const mode: Mode = switch (i) {
        0 => .Custom,
        else => blk: {
            break :blk switch (random.intRangeAtMost(u8, 0, 100)) {
                0...33 => .Low,
                34...66 => .Medium,
                67...100 => .High,
                else => unreachable,
            };
        },
    };

    std.debug.print("{}\n", .{mode});
}

This now works, going ahead and closing the issue.