019 reject destructure unused field

✓ Passing This code compiles and runs correctly.

Code

// Destructured fields are bindings: each named field must be USED or be
// spelled `_` — KORU100 per field, the same linear discipline as any
// binding. `age` is named but never read.
~import std/io

~pub event fetch {} -> { name: []const u8, age: i64 }

~proc fetch|zig { return .{ .name = "lars", .age = 44 }; }

~fetch(): { name, age } |> std/io:print.ln("only {{ name:s }}")

input.kz

Frontend must reject with:

CONTAINS unused binding 'age'

Error Verification

Actual Compiler Output

error[KORU100]: unused binding 'age'
  --> tests/regression/000_CORE_LANGUAGE/020_EVENTS_FLOWS/020_019_reject_destructure_unused_field/input.kz:10:0
    |
 10 | ~fetch(): { name, age } |> std/io:print.ln("only {{ name:s }}")
    | ^
  hint: discard the destructured field using `_` if not needed

Flows

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fetch

Test Configuration

MUST_FAIL

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