How to set the floating point mode in a struct or module scope by using a comptime block?

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1

The doc of @setRuntimeSafety says:

The floating point mode is inherited by child scopes, and can be overridden in any scope. You can set the floating point mode in a struct or module scope by using a comptime block.

But it looks setting the floating point mode in a struct or module scope by using a comptime block doesn’t work.

var x: f64 = 0.0;

comptime {
    @setFloatMode(.optimized); // Not work.
}

pub fn main() void {
    //@setFloatMode(.optimized); // This line works.
    
    const y = 0.0 / x;
    @import("std").debug.print("{}\n", .{y}); 
}