comptime should not be allowed in type expressions: e.g. var foo: comptime u64

[momumi]

A comptime variable in zig uses the syntax comptime var foo: u64, however the compiler also accepts var foo: comptime u64. The compiler seems treat the latter case as equivalent to var foo: u64, but I think it should be a syntax error.

For example this program will compile and run without errors:

const std = @import("std");

pub fn main() void {
    var x: comptime u64 = std.time.milliTimestamp();

    std.debug.warn("time: {}\n", .{x});
}

On a slightly related note, the zig grammar in the docs seems to be very wrong/outdated (e.g. a CHAR_LITERAL would be a valid TypeExpr), but that's probably a separate issue.

[SpexGuy]

This was recently added as part of #8364. Closing this in the interest of having only one issue to track the change.