Mutually recursive nested function declarations abort at runtime with no diagnostic (exit 133, no output)

[ryoppippi]

Two function declarations nested inside another function that call each other abort at runtime. The build succeeds with no diagnostic, and the binary produces no output and no error message — just exit 133 (SIGTRAP).

The same pair of functions at module top level works correctly, so the trigger is the nesting.

Repro

export {}
function outer(n: number): number {
  function even(k: number): number {
    if (k === 0) return 1
    return odd(k - 1)
  }
  function odd(k: number): number {
    if (k === 0) return 0
    return even(k - 1)
  }
  return even(n)
}
function main() {
  console.log(`r=${outer(4)}`)
}
main()

$ bun recA.ts
r=1

$ scriptc build recA.ts -o recA     # no diagnostic
$ ./recA
$ echo $?
133

Nothing is printed on stdout or stderr.

Narrowing

shape	result
mutual recursion between nested declarations	abort, exit 133
the same mutual recursion at top level	works (r=1)
nested, plain forward reference (first() calls second(), no cycle)	works
nested, backward reference only	works

So it is specifically the cycle among nested declarations, not a forward reference on its own:

// works
function outer(): number {
  function first(): number { return second() + 1 }
  function second(): number { return 41 }
  return first()
}

Where I hit it

A recursive-descent parser written the conventional way — primary/comparison/and/or nested inside parse(), with primary() calling or() for a parenthesised sub-expression. Compiled clean, aborted on every input. Restructuring to top-level functions over an explicit cursor object fixed it.

Impact

Silent, message-free abort is the worst failure mode: there is nothing to search for and nothing to point at. Even if the fix takes a while, a compile-time refusal naming the cycle would make this tractable.

Environment

• scriptc 0.0.17, @scriptc/compiler 0.0.17
• macOS 26.5.2, arm64, Node v24.18.0
• Static build (no --dynamic), default backend