From d8969465a546826d093dce74b97c8e43eb75a167 Mon Sep 17 00:00:00 2001
From: metagn <metagngn@gmail.com>
Date: Sat, 29 Oct 2022 08:20:04 +0300
Subject: [PATCH] alternate fix + test for #12094, refs #13804 (#20686)

(cherry picked from commit cb3af8ad397b986699a36d1fae9052bf11250b06)
---
 compiler/semstmts.nim           |  3 +--
 compiler/semtempl.nim           |  2 +-
 tests/template/tunderscore1.nim | 11 +++++++++++
 3 files changed, 13 insertions(+), 3 deletions(-)
 create mode 100644 tests/template/tunderscore1.nim

diff --git a/compiler/semstmts.nim b/compiler/semstmts.nim
index 826b9dead9aca..7b5b2f0bc9b8e 100644
--- a/compiler/semstmts.nim
+++ b/compiler/semstmts.nim
@@ -360,8 +360,7 @@ proc addToVarSection(c: PContext; result: PNode; orig, identDefs: PNode) =
     result.add identDefs
 
 proc isDiscardUnderscore(v: PSym): bool =
-  # template generated underscore symbol name starts with _`gensym
-  if v.name.s == "_" or v.name.s.startsWith("_`"):
+  if v.name.s == "_":
     v.flags.incl(sfGenSym)
     result = true
 
diff --git a/compiler/semtempl.nim b/compiler/semtempl.nim
index 4ef20db5d1d69..c7bad18603904 100644
--- a/compiler/semtempl.nim
+++ b/compiler/semtempl.nim
@@ -227,7 +227,7 @@ proc addLocalDecl(c: var TemplCtx, n: var PNode, k: TSymKind) =
           closeScope(c)
     let ident = getIdentNode(c, n)
     if not isTemplParam(c, ident):
-      if n.kind != nkSym:
+      if n.kind != nkSym and not (n.kind == nkIdent and n.ident.s == "_"):
         let local = newGenSym(k, ident, c)
         addPrelimDecl(c.c, local)
         styleCheckDef(c.c, n.info, local)
diff --git a/tests/template/tunderscore1.nim b/tests/template/tunderscore1.nim
new file mode 100644
index 0000000000000..71af39501e955
--- /dev/null
+++ b/tests/template/tunderscore1.nim
@@ -0,0 +1,11 @@
+discard """
+  errormsg: "undeclared identifier: '_'"
+"""
+
+# issue #12094, #13804
+
+template foo =
+  let _ = 1
+  echo _
+
+foo()