for rejects an inline suite that if and while accept

• Type: bug (parse inconsistency) — Track N
• Found: 2026-08-06, bughunting. Loud, not silent — but it rejects ordinary Python and the inconsistency with if/while is the tell that it is an oversight rather than a deliberate subset boundary.

Measured (self-hosted binary at 412fda7a3)

f = 1
for i in range(1, 5): f *= i     # pascal26:2: error: unexpected token
print(f)                         #   Expected: newline, but got: f (Kind: 1, Line: 2)

The same body indented on the next line compiles and prints 24. The other two compound statements accept the inline form today:

x = 1
if True: x += 5        # OK, prints 6
while x < 5: x += 1    # OK, prints 5

The body form is irrelevant — for i in range(1, 5): f = f * i fails the same way, so it is the inline suite after for, not the augmented assignment.

Why it is worth fixing rather than documenting

One-liner for is common in real Python, and this shape also masks other bugs: the case that surfaced it was a factorial loop written to probe arbitrary-precision arithmetic, and the parse error hid the actual (wrong-value) result until the loop was re-indented — see [[bug-nilpy-augmented-assignment-truncates-to-32-bits]].

Note [[bug-nilpy-one-line-class-body-restraint-is-no-longer-enforced]] is the neighbouring one-line-suite ticket; whoever takes either should read both, since the suite parser is shared ground.

Gate

Per-fix loop. A .npy test with inline for, if and while suites (and a for … else) diffed against CPython.

Log

• 2026-08-06 — resolved. PyParseSuite already accepted both the indented and the one-line body, and PyParseForIn (the container form) already used it — which is exactly why for x in xs: body worked while for i in range(4): body did not. The RANGE arm of PyParseFor and PyParseForZip hand-rolled Expect(newline) + Expect(indent) + PyParseBlock + Expect(dedent) instead; both now call PyParseSuite.

  Two lines of real change. The bug was not the parser lacking the ability — it was two sites not using the routine that already had it, which is the double-case shape devdocs/dev/normalise-dont-special-case.md is about.

  Verified: test/test_nilpy_for_inline_suite.npy (new, in make test-nilpy) — inline range / container / zip bodies, semicolon-separated statements on the line, an inline body that is itself a compound statement, for/else over an inline body, the indented form, and a nested inline-inside-indented loop. All lines match CPython. tools/gate.sh quick GREEN.