// Entry-point signature gate (ERR step E4.2). `main` must take no parameters
// and have a single-slot return: void, an integer (POSIX exit code), or `-> !`
// (the error tag rides the single return register). Anything else is a clean
// diagnostic — previously `main :: () -> string` SEGFAULTED (the JIT calls main
// as `() -> i32`, so a string return is read as garbage). The value-carrying
// failable `-> (T, !)` is also rejected for now: its multi-slot return ABI-
// mismatches the entry-point call (lands with the E4.2 wrapper). Accepted
// shapes are exercised elsewhere (e.g. 238 for integer-exit truncation).
// This file is expected to FAIL compilation (exit 1).
//
// Run: ./zig-out/bin/sx run examples/239-main-signature-reject.sx

#import "modules/std.sx";

main :: () -> string {        // ERROR: return type must be void, an integer, or `!`
    return "not an exit code";
}