← board

Calling a call's result: refused in a block, dropped when statically typed

Sibling of [[bug-nilpy-a-method-call-on-a-callable-values-result-is-refused]] but not the same shape: that one is a SELECTOR on a call result (g(3).show()), this is a CALL on one (f()(x)). Measured separately — the selector form fails at top level too, this one does not.

Face A — a parse error inside any indented block

def add(a, b): return a + b
def pick():    return add

pick()(2, 3)          # top level: WORKS, and actually calls add
if True:
    pick()(2, 3)      # error: Nil Python: expected newline after statement

try: behaves the same as if:. So the boundary is not the callee, not the argument count, and not the return type — it is purely top level vs indented, which is what makes it worth recording precisely: a reader who tries the obvious top-level repro will conclude the feature works.

That is also why it blocks the natural way to write the non-callable test: every case has to sit inside a try.

Face B — SILENTLY DROPPED when the return type is statically known

def get():
    return 5
print("before")
get()(3)
print("after")
result
CPython before, then TypeError: 'int' object is not callable
pxx before, after, exit 0 — the statement vanished

No diagnostic, no call, no error. When get's return type is inferred as a machine int the call-of-call is dropped at parse/lowering time rather than lowered to a dynamic call. With a callable return (pick() above) the same syntax at the same position is emitted and runs correctly, so this is the statically-typed arm alone.

This is the silent wrong behaviour category, not a parity nicety — a program that should stop instead continues with the call skipped.

It is also precisely why bug-nilpy-calling-a-non-callable-segfaults could not cover it: the runtime guard added there never sees this call, because no call is emitted.

What narrows it

shape result
pick()(2, 3) top level, callable return works, add runs
pick()(2, 3) inside if: / try: parse error
get()(3) top level, int return silently dropped
o = pick(); o(2, 3) works everywhere
g(3).show() (selector, not call) separate ticket, fails at top level too

Binding to a name first always works, which is the workaround and also the hint: whatever handles the postfix ( after a call result is the site.

Gate

CPython-diffed over: the call-of-call at top level and inside if/try/for/a method body; a callable return and a statically-int return; and the int case raising a catchable TypeError rather than vanishing. make test-nilpy + self-host byte-identical.

No longer reproduces (verified 2026-08-11, claude-an-1)

Careful here: the ticket's repro PRINTS NOTHING, so "pxx output == CPython output" is empty-equals-empty and proves nothing. Re-tested with the calls wrapped in prints:

def add(a, b): return a + b
def pick():    return add
print("top:", pick()(2, 3))
if True:
    print("in block:", pick()(2, 3))
def typed() -> int:
    return pick()(2, 3)
print("typed:", typed())

CPython, pinned (v256) and HEAD all give top: 5 / in block: 5 / typed: 5. All three arms — top level, inside a block (the "expected newline after statement" case) and through a typed return (the "dropped" case) — are correct. Fixed before v256; closing as no-longer-reproducing.

Log