Comptime ptrs incorrectly compare as unequal, if derived in different ways

[topolarity]

Zig Version

0.10.0-dev.1534+1cf134632

Steps to Reproduce

test {
    try testPtrEql(); // passes
    try comptime testPtrEql(); // fails
}

fn testPtrEql() !void {
    const S = extern struct {
        a: f32,
        b: [4]u8,
        c: f32,
    };

    var s = S{ .a = 1.5, .b = [_]u8{1, 2, 3, 4}, .c = 2.5};
    var ptr1: *const u8 = &s.b[0];
    var ptr2: *const u8 = &@as(*const [@sizeOf(S)] u8, @ptrCast(&s))[4];
    _ = &ptr1;
    _ = &ptr2;

    // These two pointers are derived in different ways, but
    // they should still be equal
    try expect(ptr1 == ptr2);
}

This can also be done in any number of other ways. For example, by creating a [*]T pointing to one field and constructing an elem ptr that happens to line up with another field.

Expected Behavior

Test should pass.

Actual Behavior

Fails in both stage1 and stage2.

[mitchellh]

Also, a real simple one: &val == &val Fails. I don’t have the test on hand but that is still an issue. There is a behavior test covering it that is currently skipped.