From e70379811b2b2b2d3d8e4fad1c7573ea30074054 Mon Sep 17 00:00:00 2001
From: ringabout <43030857+ringabout@users.noreply.github.com>
Date: Sun, 6 Nov 2022 22:25:55 +0800
Subject: [PATCH] fixes regression #17121; adding doc comment in importc proc
 makes it silently noop at CT (#20766)

* fixes regression #17121; adding doc comment in importc proc makes it silently noop at CT

* Update compiler/vmgen.nim

Co-authored-by: Andreas Rumpf <rumpf_a@web.de>
(cherry picked from commit a228e331f30def00d4369d4e792c7454963d8c4e)
---
 compiler/vmgen.nim  | 11 ++++++++++-
 tests/vm/t17121.nim |  9 +++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 tests/vm/t17121.nim

diff --git a/compiler/vmgen.nim b/compiler/vmgen.nim
index 4cfaa86b06..af99d45e21 100644
--- a/compiler/vmgen.nim
+++ b/compiler/vmgen.nim
@@ -1630,11 +1630,20 @@ proc genTypeLit(c: PCtx; t: PType; dest: var TDest) =
   n.typ = t
   genLit(c, n, dest)
 
+proc isEmptyBody(n: PNode): bool =
+  case n.kind
+  of nkStmtList:
+    for i in 0..<n.len:
+      if not isEmptyBody(n[i]): return false
+    result = true
+  else:
+    result = n.kind in {nkCommentStmt, nkEmpty}
+
 proc importcCond*(c: PCtx; s: PSym): bool {.inline.} =
   ## return true to importc `s`, false to execute its body instead (refs #8405)
   if sfImportc in s.flags:
     if s.kind in routineKinds:
-      return getBody(c.graph, s).kind == nkEmpty
+      return isEmptyBody(getBody(c.graph, s))
 
 proc importcSym(c: PCtx; info: TLineInfo; s: PSym) =
   when hasFFI:
diff --git a/tests/vm/t17121.nim b/tests/vm/t17121.nim
new file mode 100644
index 0000000000..bf2d6423fc
--- /dev/null
+++ b/tests/vm/t17121.nim
@@ -0,0 +1,9 @@
+discard """
+  errormsg: "cannot 'importc' variable at compile time; c_printf"
+"""
+
+proc c_printf*(frmt: cstring): cint {.importc: "printf", header: "<stdio.h>", varargs, discardable.} =
+  ## foo bar
+  runnableExamples: discard
+static:
+  let a = c_printf("abc\n")