From 1e72e254105f5b167589591c87c0995d3b73d973 Mon Sep 17 00:00:00 2001
From: ringabout <43030857+ringabout@users.noreply.github.com>
Date: Thu, 8 Dec 2022 17:37:02 +0800
Subject: [PATCH] fixes #9839; fixes noReturn pragma doesn't work for
 non-simple templates (#21048)

(cherry picked from commit c5eb3fd4f0798eaa31b834f5dbe3f563e55c2b03)
---
 compiler/semstmts.nim              |  9 ++++++---
 tests/controlflow/tunreachable.nim | 32 ++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 3 deletions(-)
 create mode 100644 tests/controlflow/tunreachable.nim

diff --git a/compiler/semstmts.nim b/compiler/semstmts.nim
index d650ab3d09..3436ea0396 100644
--- a/compiler/semstmts.nim
+++ b/compiler/semstmts.nim
@@ -2410,9 +2410,12 @@ proc semStmtList(c: PContext, n: PNode, flags: TExprFlags, expectedType: PType =
     else:
       n.typ = n[i].typ
       if not isEmptyType(n.typ): n.transitionSonsKind(nkStmtListExpr)
-    if n[i].kind in nkLastBlockStmts or
-        n[i].kind in nkCallKinds and n[i][0].kind == nkSym and
-        sfNoReturn in n[i][0].sym.flags:
+    var m = n[i]
+    while m.kind in {nkStmtListExpr, nkStmtList} and m.len > 0: # from templates
+      m = m.lastSon
+    if m.kind in nkLastBlockStmts or
+        m.kind in nkCallKinds and m[0].kind == nkSym and
+        sfNoReturn in m[0].sym.flags:
       for j in i + 1..<n.len:
         case n[j].kind
         of nkPragma, nkCommentStmt, nkNilLit, nkEmpty, nkState: discard
diff --git a/tests/controlflow/tunreachable.nim b/tests/controlflow/tunreachable.nim
new file mode 100644
index 0000000000..fe5568218c
--- /dev/null
+++ b/tests/controlflow/tunreachable.nim
@@ -0,0 +1,32 @@
+discard """
+  cmd: "nim check --hints:off --warningAsError:UnreachableCode $file"
+  action: "reject"
+  nimout: '''
+tunreachable.nim(23, 8) Error: unreachable code after 'return' statement or '{.noReturn.}' proc [UnreachableCode]
+tunreachable.nim(30, 8) Error: unreachable code after 'return' statement or '{.noReturn.}' proc [UnreachableCode]
+'''
+"""
+  
+# bug #9839
+template myquit1():untyped=
+  ## foo
+  quit(1)
+template myquit2():untyped=
+  echo 123
+  myquit1()
+
+proc main1()=
+
+  # BUG: uncommenting this doesn't give `Error: unreachable statement`
+  myquit2()
+
+  echo "after"
+
+main1()
+
+proc main2() =
+  myquit1()
+
+  echo "after"
+
+main2()