// E6BR-5 regression — the open nested-pattern ambiguity hole that PAUSED E6b,
// re-filed under Fork C as a RESOLVER-TARGET regression (NOT an E6b attempt-6).
//
// Shape: a param-impl SOURCE pattern whose concrete `*Box` leaf is NESTED inside
// an inner parameterized form that itself carries unbound pack parts
// (`Closure(*Box, ..$inner) -> $IR`). On flow/stdlib/E6b the bug lived in
// `walkConcreteSigArgs` (lower.zig:14686): it SKIPS any direct arg that has an
// unbound part instead of RECURSING into it, so the nested concrete `*Box` leaf
// is never ambiguity-checked — `impl ... for Closure(Closure(*Box, ..)->.., ..)->..`
// compiled rc=0 while the DIRECT `Closure(*Box, ..)` form (0829) errored. It was
// the 3rd consecutive major on the parameterized-pattern surface
// (bare E6BR-2 -> wrapped E6BR-4 -> nested E6BR-5).
//
// CURRENT BASE (wt-stdlib-base, E6b unmerged): both the direct AND the nested
// concrete leaf silently resolve via the pre-E6BR-4 no-author wrapper path
// (`type_bridge.resolveTemplateSignatureType`, global last-wins) — this program
// exits 0 with NO diagnostic. Run it to see the fail-before.
//
// TARGET (Fork C, flips active+green at S3.9): the whole-AST resolver walks EVERY
// reference position — including nested parameterized-pattern leaves — so the
// nested `Box` is ambiguity-checked like any other reference and the build emits
// the loud "type 'Box' is ambiguous" diagnostic and exits 1. The exact golden
// bytes are produced by the resolver at S3.9 (no oracle produces them today);
// see ../expected/e6br5-nested-pack-source-ambiguous.target.md for the spec.
//
// WHY SUBSUMED (one line): a resolver that resolves every reference position has
// no notion of "skip a nested arg with an unbound sibling" — the nested `*Box`
// leaf is resolved by construction, so the hole cannot exist.

#import "modules/std.sx";
#import "e6br5-nested-pack-source-ambiguous/a.sx";
#import "e6br5-nested-pack-source-ambiguous/b.sx";

Block :: struct { tag: s32; }

Sink :: protocol(T: Type) {
    convert :: () -> T;
}

impl Sink(Block) for Closure(Closure(*Box, ..$inner) -> $IR, ..$args) -> $R {
    convert :: (self: Closure(Closure(*Box, ..$inner) -> $IR, ..$args) -> $R) -> Block {
        .{ tag = 0 }
    }
}

main :: () -> s32 {
    0
}