// Phase 4 (FFI-linkage) interplay diagnostic: `extern` and `export` are the two
// values of the same linkage axis — a declaration is either an import (`extern`)
// or a definition (`export`), never both. The parser rejects the redundant
// second keyword with a clear message (instead of the bare "expected ';'" the
// body parser would otherwise emit).
//
// Expected: one error caret on the second keyword; exit 1.

f :: (a: i32) -> i32 extern export;

main :: () -> i32 { 0 }