From 9e3a82287731a13d49918586839e30b26d4863a8 Mon Sep 17 00:00:00 2001
From: Mark Spanbroek <mark@spanbroek.net>
Date: Wed, 10 Aug 2022 11:11:45 +0200
Subject: [PATCH] Fix: disregard early symbol lookup for error variable

---
 questionable/withoutresult.nim | 22 +++++++++++++++++++++-
 testmodules/result/test.nim    |  1 +
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/questionable/withoutresult.nim b/questionable/withoutresult.nim
index a34ccff..cabba18 100644
--- a/questionable/withoutresult.nim
+++ b/questionable/withoutresult.nim
@@ -2,12 +2,32 @@ import std/macros
 import ./without
 import ./private/binderror
 
-macro without*(condition, errorname, body): untyped =
+proc undoSymbolResolution(expression, ident: NimNode): NimNode =
+  ## Finds symbols in the expression that match the `ident` and replaces them
+  ## with `ident`, effectively undoing any symbol resolution that happened
+  ## before.
+
+  const symbolKinds = {nnkSym, nnkOpenSymChoice, nnkClosedSymChoice}
+
+  if expression.kind in symbolKinds and eqIdent($expression, $ident):
+    return ident
+
+  for i in 0..<expression.len:
+    expression[i] = undoSymbolResolution(expression[i], ident)
+
+  expression
+
+macro without*(condition, errorname, body: untyped): untyped =
   ## Used to place guards that ensure that a Result contains a value.
   ## Exposes error when Result does not contain a value.
 
   let errorIdent = ident $errorname
 
+  # Nim's early symbol resolution might have picked up a symbol with the
+  # same name as our error variable. We need to undo this to make sure that our
+  # error variable is seen.
+  let body = body.undoSymbolResolution(errorIdent)
+
   quote do:
     var error: ref CatchableError
 
diff --git a/testmodules/result/test.nim b/testmodules/result/test.nim
index b1bff65..579ddb6 100644
--- a/testmodules/result/test.nim
+++ b/testmodules/result/test.nim
@@ -286,6 +286,7 @@ suite "result":
 
     proc shouldCompile(_: type int): ?!int =
       without _ =? int.failure "error", existingName:
+        check existingName.msg == "error"
         return success 42
 
     discard int.shouldCompile()