// letshadow — #152 regression pin. A `let` binding must NOT be visible
// during its OWN initializer: `let x = f(x)` evaluates f(x) in the OUTER
// scope (Hare: harec check.c clet runs cexpr before scope_define). Both
// stages once linked the binding into the cgen localfind chain BEFORE
// emitting the init, so the init read the fresh UNINIT shadow slot — a
// silent miscompile identical on both stages (byte-id GREEN over it), so
// this is a RUNTIME assertion. Signalled-then-exit(+10) pinpoints the row.
//
// Run with `out/bin/ww run test/wcc/989_letshadow.ww`; exit 0 = all pass.

package main;

import os;

let signalled: i32 = 0;
fn fail() void = { os.exit(signalled + 10); };

fn id(s: str) str = { return s; };

// Row 1 — PARAM self-shadow (ken's headline, the c3-posix shape):
// `let p = id(p)` must read the PARAM p, not the uninit shadow.
// "hello" → len(5)*100 + 'h'(104) = 604 (pre-fix: 0, the zero slot).
fn paramshadow(p: str) i32 = {
	let p = id(p);
	return (p.len: i32) * 100 + (p[0]: i32);
};

// Row 2 — LET shadows an OUTER-scope LET in its OWN init. ww rejects
// same-block redeclaration, so the inner let lives in a nested block;
// its init must read the OUTER x (=5) since the inner x isn't linked
// yet → 6 (pre-fix: garbage from the fresh uninit shadow slot).
fn letinletinit() i32 = {
	let x: i32 = 5;
	let r: i32 = 0;
	{
		let x: i32 = x + 1;
		r = x;
	};
	return r;
};

// Row 3 — CONTROL (rename, no shadow). Already correct both pre/post;
// pins no-regression. "hi" → 2.
fn renamecontrol(p: str) i32 = {
	let p2 = id(p);
	return p2.len: i32;
};

// Row 4 — UNIFORM-arm proof: arrlit self-ref. The inner `let a = [a, a]`
// (nested block; ww rejects same-block redeclaration) shadows the outer
// a; both elements must read the OUTER a (=3) → 6. Proves the N_ARRLIT
// arm defers the link too, not just the value-init arm.
fn arrlitselfref() i32 = {
	let a: i32 = 3;
	let r: i32 = 0;
	{
		let a: [2]i32 = [a, a];
		r = a[0] + a[1];
	};
	return r;
};

export fn main() i32 = {
	signalled = 1; if (paramshadow("hello") != 604) { fail(); };
	signalled = 2; if (letinletinit() != 6) { fail(); };
	signalled = 3; if (renamecontrol("hi") != 2) { fail(); };
	signalled = 4; if (arrlitselfref() != 6) { fail(); };
	return 0;
};