ffi: Panic on incorrect FFI parameters

[fucksophie]

Code

const user32 = Deno.dlopen("user32.dll", {
    SystemParametersInfoA: {
        parameters: [
            "u32", 
            "u32",
            "pointer", 
            "u32", 
        ], 
        result: "i32" 
    } 
});

const result = user32.symbols.SystemParametersInfoA(0x0014, null, new TextEncoder().encode("D:/flower1.jpg"), 0x01)

Panic

============================================================
Deno has panicked. This is a bug in Deno. Please report this
at https://github.com/denoland/deno/issues/new.
If you can reliably reproduce this panic, include the
reproduction steps and re-run with the RUST_BACKTRACE=1 env
var set and include the backtrace in your report.

Platform: windows x86_64
Version: 1.17.1
Args: ["deno", "run", "--unstable", "--allow-all", "natives.ts"]

thread 'main' panicked at 'Expected ffi arg value to be an unsigned integer', ext\ffi\lib.rs:281:6
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Mitigation

In this case, you can replace the null in user32.symbols.Syst... to 0, to match the symbol's parameters and the panic no longer occurs.

[fucksophie]

I think
64fe46b would fix this