150 effect required arm presence test rejected

✗ Failing This test is currently failing.

Failed: wrong-error

Error Details

output_emitted.zig:43:9: error: expected type 'bool', found 'fn (i64) void'

Failure Output

🎯 Compiler coordination: Passes: 15 (flow-based: frontend, analysis, emission)
Error: output_emitted.zig:43:9: error: expected type 'bool', found 'fn (i64) void'
    if (pong) {
        ^~~~
referenced by:
    flow0: output_emitted.zig:62:43
    main: output_emitted.zig:517:22
    4 reference(s) hidden; use '-freference-trace=6' to see all references

Code

// MUST_FAIL — presence-testing a REQUIRED arm. Designed 2026-07-03: the
// presence expression (`if(pong)` / `when pong`) exists because OPTIONAL
// handlers may be absent. A required arm is always installed — the
// exhaustiveness check guarantees it — so testing for it is a meaningless
// always-true and almost certainly a misread of the contract. Reject it
// and say why, rather than folding to `true` silently.
import std/io

pub event ping { x: i64 }
! pong i64

ping = if(pong)
| then |> pong(x)
| else |> pong(0)

ping(x: 41)
! pong v |> std/io:print.ln("{{ v:d }}")

input.k

Backend must reject with:

CONTAINS 'pong'
CONTAINS always installed

Error Verification

Actual Compiler Output

🎯 Compiler coordination: Passes: 15 (flow-based: frontend, analysis, emission)
Error: output_emitted.zig:43:9: error: expected type 'bool', found 'fn (i64) void'
    if (pong) {
        ^~~~
referenced by:
    flow0: output_emitted.zig:62:43
    main: output_emitted.zig:517:22
    4 reference(s) hidden; use '-freference-trace=6' to see all references

Flows

subflow ~ping click a branch to expand · @labels scroll to their anchor

if (pong)

flow ~ping click a branch to expand · @labels scroll to their anchor

ping (x: 41)

Test Configuration

MUST_FAIL

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