// Regression for issue 0057: a match (`if subject == { case ... }`) whose arms
// ALL diverge (each `return`s) used to fail LLVM verification (a `void` phi +
// "terminator in the middle of a basic block") — lowerMatch emitted a
// value-merge phi and a fallback `const` into arm blocks that had already
// terminated. Now a fully-diverging match produces no merge phi, and a mixed
// match (some arms diverge, some yield values) materializes the merge only
// from the value-producing arms.

#import "modules/std.sx";

// All arms diverge — the match is `noreturn`, no merge phi.
classify :: (n: i32) -> i32 {
    if n == {
        case 0: return 10;
        case 1: return 20;
        else:   return 90;
    }
    return 0;                       // unreachable
}

// Mixed: value arms + a diverging arm.
pick :: (n: i32) -> i32 {
    v := if n == {
        case 0: 1;
        case 1: return 100;         // diverging arm — no fallback const after its `ret`
        else:   3;
    };
    return v + 5;
}

main :: () -> i32 {
    r : i32 = 0;
    r = r + classify(0);            // 10
    r = r + classify(1);            // 20
    r = r + classify(7);            // 90
    r = r + pick(0);                // 1 + 5 = 6
    r = r + pick(9);                // 3 + 5 = 8  (else arm)
    print("match result: {}\n", r); // 10+20+90+6+8 = 134
    return r;
}