Nested `with` blocks (#22042)

* Implemented with-nesting in underscoredCalls()

* Add tests for nested with

1 files changed, 14 insertions, 6 deletions

diff --git a/lib/std/private/underscored_calls.nim b/lib/std/private/underscored_calls.nim
index f0bcbcc74..8b0392641 100644
--- a/lib/std/private/underscored_calls.nim
+++ b/lib/std/private/underscored_calls.nim
@@ -12,6 +12,8 @@
 
 import macros
 
+proc underscoredCalls*(result, calls, arg0: NimNode)
+
 proc underscoredCall(n, arg0: NimNode): NimNode =
   proc underscorePos(n: NimNode): int =
     for i in 1 ..< n.len:
@@ -19,13 +21,19 @@ proc underscoredCall(n, arg0: NimNode): NimNode =
     return 0
 
   if n.kind in nnkCallKinds:
-    result = copyNimNode(n)
-    result.add n[0]
+    if n[0].kind in {nnkIdent, nnkSym} and n[0].eqIdent("with"):
+      expectKind n[1], {nnkIdent, nnkSym}
 
-    let u = underscorePos(n)
-    for i in 1..u-1: result.add n[i]
-    result.add arg0
-    for i in u+1..n.len-1: result.add n[i]
+      result = newStmtList()
+      underscoredCalls(result, n[2 .. ^1].newStmtList, newDotExpr(arg0, n[1]))
+    else:
+      result = copyNimNode(n)
+      result.add n[0]
+
+      let u = underscorePos(n)
+      for i in 1..u-1: result.add n[i]
+      result.add arg0
+      for i in u+1..n.len-1: result.add n[i]
   elif n.kind in {nnkAsgn, nnkExprEqExpr}:
     var field = n[0]
     if n[0].kind == nnkDotExpr and n[0][0].eqIdent("_"):