From fb31e86537dab922d91f37b8e4954e0bfa748932 Mon Sep 17 00:00:00 2001
From: ringabout <43030857+ringabout@users.noreply.github.com>
Date: Wed, 1 Apr 2026 05:32:24 +0800
Subject: [PATCH] fixes #25632; errors incompatibility between {.error.} and
 {.exportc} pragmas in semProcAux (#25639)

fixes #25632
fixes #25631
fixes #25630

This pull request introduces a compatibility check between the
`{.error.}` and `{.exportc.}` pragmas in procedure declarations.
Specifically, it prevents a procedure from being marked with both
pragmas at the same time, as this combination is now considered invalid.

Pragma compatibility enforcement:

* Added a check in `semProcAux` (in `compiler/semstmts.nim`) to emit a
local error if a procedure is declared with both `{.error.}` and
`{.exportc.}` pragmas, preventing their incompatible usage.
---
 compiler/semstmts.nim | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/compiler/semstmts.nim b/compiler/semstmts.nim
index 7e07143837..285b84cfc7 100644
--- a/compiler/semstmts.nim
+++ b/compiler/semstmts.nim
@@ -2552,6 +2552,9 @@ proc semProcAux(c: PContext, n: PNode, kind: TSymKind,
   if not hasProto:
     implicitPragmas(c, s, n.info, validPragmas)
 
+  if {sfError, sfExportc} * s.flags == {sfError, sfExportc}:
+    localError(c.config, n.info, "{.error.} and {.exportc.} pragmas are incompatible")
+
   if n[pragmasPos].kind != nkEmpty and sfBorrow notin s.flags:
     setEffectsForProcType(c.graph, s.typ, n[pragmasPos], s)
   s.typ.incl tfEffectSystemWorkaround