From 1124bb88f87025348ce0a71863dad30d48d6b2c2 Mon Sep 17 00:00:00 2001
From: ringabout <43030857+ringabout@users.noreply.github.com>
Date: Fri, 14 Aug 2026 22:45:17 +0800
Subject: [PATCH] Add tests for nimvm scope handling and undeclared identifiers

---
 tests/vm/t26048.nim           |  9 +++++++++
 tests/vm/twhennimvmscope1.nim | 12 ++++++++++++
 tests/vm/twhennimvmscope2.nim | 13 +++++++++++++
 tests/vm/twhennimvmscope3.nim | 10 ++++++++++
 tests/whenstmt/t26044.nim     | 16 ++++++++++++++++
 5 files changed, 60 insertions(+)
 create mode 100644 tests/vm/t26048.nim
 create mode 100644 tests/vm/twhennimvmscope1.nim
 create mode 100644 tests/vm/twhennimvmscope2.nim
 create mode 100644 tests/vm/twhennimvmscope3.nim
 create mode 100644 tests/whenstmt/t26044.nim

diff --git a/tests/vm/t26048.nim b/tests/vm/t26048.nim
new file mode 100644
index 0000000000..7191dac6ce
--- /dev/null
+++ b/tests/vm/t26048.nim
@@ -0,0 +1,9 @@
+# issue #26048, `$` declarations must not leak from `when nimvm`
+
+type U = object
+
+when nimvm:
+  proc `$`(_: U): string = "s"
+
+var n: U
+doAssert $n != "s"
diff --git a/tests/vm/twhennimvmscope1.nim b/tests/vm/twhennimvmscope1.nim
new file mode 100644
index 0000000000..c535ad3437
--- /dev/null
+++ b/tests/vm/twhennimvmscope1.nim
@@ -0,0 +1,12 @@
+# issue #23687
+
+when nimvm:
+  proc mytest(a: int) =
+    echo a
+else:
+  template mytest(a: int) =
+    echo a + 42
+
+proc xxx() =
+  mytest(100) #[tt.Error
+  ^ undeclared identifier: 'mytest']#
diff --git a/tests/vm/twhennimvmscope2.nim b/tests/vm/twhennimvmscope2.nim
new file mode 100644
index 0000000000..70d8319f5a
--- /dev/null
+++ b/tests/vm/twhennimvmscope2.nim
@@ -0,0 +1,13 @@
+# issue #23688
+
+when nimvm:
+  proc mytest(a: int) =
+    echo a
+else:
+  template mytest(a: untyped) =
+    echo a + 42
+
+proc xxx() =
+  mytest(100) #[tt.Error
+  ^ undeclared identifier: 'mytest']#
+xxx()
diff --git a/tests/vm/twhennimvmscope3.nim b/tests/vm/twhennimvmscope3.nim
new file mode 100644
index 0000000000..1b99519db7
--- /dev/null
+++ b/tests/vm/twhennimvmscope3.nim
@@ -0,0 +1,10 @@
+# issue #13450, example 3
+
+proc bar() =
+  when nimvm:
+    let y = 1
+  else:
+    let y = 2
+  discard y #[tt.Error
+          ^ undeclared identifier: 'y']#
+bar()
diff --git a/tests/whenstmt/t26044.nim b/tests/whenstmt/t26044.nim
new file mode 100644
index 0000000000..ec21f059ff
--- /dev/null
+++ b/tests/whenstmt/t26044.nim
@@ -0,0 +1,16 @@
+# issue #26044
+
+discard """
+  cmd: "nim check --hints:off --warnings:off $file"
+  action: reject
+  nimout: '''
+t26044.nim(15, 11) Error: undeclared identifier: 'g'
+t26044.nim(15, 11) Error: expression 'g' has no type (or is ambiguous)
+'''
+"""
+
+proc p =
+  when nimvm:
+    var g: int
+  discard g
+p()