ringabout 88a18de44f fixes #25851; ensure --panics:on does not skip nimErr_ check after closure calls (#25855) ...

fixes #25851

## Summary: `--panics:on` drops `nimErr_` check after closure calls
(#25851)

### Bug

With `--exceptions:goto` and `--panics:on`, the compiler skipped the
`nimErr_` check after indirect closure calls whose result flows directly
into another call (e.g., `result.add elem(src)`). A raise inside the
closure was silently swallowed — the loop continued, and the next
`raise` hit the already-set `nimInErrorMode` flag, overflowing its
`bool` storage into `OverflowDefect`.

### Root Cause

**ast.nim** — `canRaise` checked `fn.typ.n[0].len < effectListLen` first
(false after the expansion) and then `exceptionEffects != nil` (also
false, nil), so it returned `false` — meaning "cannot raise." The C
codegen trusted this and omitted the `nimErr_` check.

### Fix

**ast.nim** — `canRaise` now treats `nil` `exceptionEffects` as "unknown
→ can raise" (`exceptionEffects == nil` as an additional true
condition). This is defense-in-depth: even if some other path expands
the list but leaves `exceptionEffects` nil (e.g., a type with `{.tags.}`
but no `{.raises.}`), the error check is still emitted.

### Test

tclosure_err_panic_goto.nim — exercises the double-trigger pattern
(`drawBool` sets the error flag → closure call must propagate it) with
`matrix: "; --panics:on"` covering both exception modes.

2026-06-01 16:21:37 +02:00

..

tclosure_err_panic_goto.nim

fixes #25851; ensure --panics:on does not skip nimErr_ check after closure calls (#25855)

2026-06-01 16:21:37 +02:00