alternate fix + test for #12094, refs #13804 (#20686)

(cherry picked from commit cb3af8a)
nim-lang · Apr 25, 2023 · d896946 · d896946
1 parent bf4c882
commit d896946
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Showing 3 changed files with 13 additions and 3 deletions.
diff --git 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
@@ -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
@@ -0,0 +1,11 @@
+discard """
+  errormsg: "undeclared identifier: '_'"
+"""
+
+# issue #12094, #13804
+
+template foo =
+  let _ = 1
+  echo _
+
+foo()