fix #18327 (#18328)

Author: ringabout

compiler/semtypes.nim

@@ -1295,7 +1295,7 @@ proc semProcTypeNode(c: PContext, n, genericParams: PNode,
         let param = strTableGet(c.signatures, arg.name)
         if param != nil: typ = param.typ
         else:
-          localError(c.config, a.info, "parameter '$1' requires a type" % param.name.s)
+          localError(c.config, a.info, "parameter '$1' requires a type" % arg.name.s)
           typ = errorType(c)
       let lifted = liftParamType(c, kind, genericParams, typ,
                                  arg.name.s, arg.info)

tests/errmsgs/t18327.nim

@@ -0,0 +1,5 @@
+discard """
+  errormsg: "parameter 'n' requires a type"
+"""
+
+proc fn3(n) = discard