@intToEnum not checking for value out of range of enum tag type

[euclidianAce]

Zig Version

0.11.0-dev.1026+4172c2916

Steps to Reproduce and Observed Behavior

// enum.zig
const std = @import("std");
pub fn main() void {
    const E = enum(u3) { a, b, c, _ };
    std.debug.print("{}, {}\n", .{
        @intToEnum(E, 100),
        @intToEnum(E, 101),
    });
}

$ zig run enum.zig 
enum.main.E(4), enum.main.E(5)

It currently seems to just mask off the upper bits without checking that 100 is representable in a u3.

Expected Behavior

A safety check of some kind as documented here

Attempting to convert an integer which represents no value in the chosen enum type invokes safety-checked Undefined Behavior.

Furthermore, @intToEnum should arguably take the tag type of the given enumeration rather than anytype to prevent this at the type level.

@intToEnum(comptime DestType: type, integer: anytype) DestType
// vs.
@intToEnum(comptime DestType: type, integer: std.meta.Tag(DestType)) DestType

Possibly related:

• invalid enum value not always detected where enum size is not explicit #11761

[Vexu]

Furthermore, @intToEnum should arguably take the tag type of the given enumeration rather than anytype to prevent this at the type level.

This was intentionally changed in bb38931

Possibly related:

• invalid enum value not always detected where enum size is not explicit #11761

That is a runtime bug and this is a comptime bug, similar but unrelated.