3c738695dc
Erasing a type to a protocol when it conforms only via a free function (not an explicit impl P for T) built a vtable of unreachable thunks -> SIGABRT on first dispatch, with no diagnostic. Per specs.md erasure is impl-driven, not structural, so the erasure was never valid. Add a conformance gate (firstUnimplementedMethod in buildProtocolValue, src/ir/lower/protocol.zig): emit a located diagnostic when a protocol method has no reachable impl, or when an impl method introduces its own type params (signature mismatch — it bails lazyLowerFunction and would reach the unreachable thunk). A std.debug.panic tripwire guards the diagnostics==null path so a non-conforming erasure can never silently ship as undef. Gate<->thunk equivalence verified bidirectional. Regressions: protocols/0419 (positive struct-field dispatch), diagnostics/1197 (no-impl) + 1198 (generic-method signature mismatch). Updated memory/0808 (it erased a non-conforming type that never dispatched). Verified by 3+1 adversarial reviews, suite 788/0. Filed adjacent bug 0178 (protocol impl method type-mismatch silent miscompile).
23 lines
1.1 KiB
Plaintext
23 lines
1.1 KiB
Plaintext
// Erasing a concrete type to a protocol whose `impl` method introduces its OWN
|
|
// type parameter is a hard error, not a silent SIGABRT. Regression (issue 0176,
|
|
// adversarial-review gap 1): `impl Speaker for Dog { speak :: (self: *Dog, $T:
|
|
// Type) }` has a matching qualified name `Dog.speak`, so the conformance gate
|
|
// used to ACCEPT it — but the thunk's `lazyLowerFunction("Dog.speak")` bails on
|
|
// `type_params.len > 0` (generics are monomorphized, not registered), so
|
|
// `resolveFuncByName` returns null and the thunk hit its `else => unreachable`
|
|
// arm: a SILENT SIGABRT (exit 133, no output) at the first dispatch. The gate
|
|
// now mirrors the thunk exactly — a method that introduces its own type params
|
|
// is a SIGNATURE MISMATCH, reported here at the erasure site (exit 1).
|
|
|
|
#import "modules/std.sx";
|
|
|
|
Speaker :: protocol { speak :: (self: *Self) -> i64; }
|
|
Dog :: struct { n: i64 = 0; }
|
|
impl Speaker for Dog { speak :: (self: *Dog, $T: Type) -> i64 { return self.n; } }
|
|
|
|
main :: () {
|
|
d := Dog.{ n = 42 };
|
|
s : Speaker = d; // <- 'Dog.speak' has a mismatched signature
|
|
print("{}\n", s.speak());
|
|
}
|