From 2c6191aa4da97acdc6dc40e9a959e1ec75fae4d4 Mon Sep 17 00:00:00 2001
From: ringabout <43030857+ringabout@users.noreply.github.com>
Date: Tue, 9 Jun 2026 04:59:16 +0800
Subject: [PATCH] fixes #22122; raise effects for complex expressions (#25845)

fixes #22122

The root cause is in the effect tracker: raise was recording the whole
conditional expression as one exception source, so semantic checking
only saw the widened common base type instead of the concrete exception
classes from each branch.

(cherry picked from commit e942da94b5b52fa7e09b133d52125037ba69c7b7)
---
 compiler/sempass2.nim          | 22 +++++++++-
 tests/effects/tcase_raises.nim | 74 ++++++++++++++++++++++++++++++++++
 2 files changed, 95 insertions(+), 1 deletion(-)
 create mode 100644 tests/effects/tcase_raises.nim

diff --git a/compiler/sempass2.nim b/compiler/sempass2.nim
index 4ff8ca3126..73c849b3a9 100644
--- a/compiler/sempass2.nim
+++ b/compiler/sempass2.nim
@@ -496,6 +496,26 @@ proc addRaiseEffect(a: PEffects, e, comesFrom: PNode) =
     if not isDefectException(e.typ):
       throws(a.exc, e, comesFrom)
 
+proc addRaiseEffectsFromExpr(a: PEffects, e, comesFrom: PNode) =
+  if e.isNil:
+    return
+  let x = skipConvCastAndClosure(e)
+  case x.kind
+  of nkStmtList, nkStmtListExpr, nkBlockStmt, nkBlockExpr:
+    if x.len > 0:
+      addRaiseEffectsFromExpr(a, x.lastSon, comesFrom)
+  of nkIfExpr, nkIfStmt:
+    for branch in items(x):
+      if branch.len > 0:
+        addRaiseEffectsFromExpr(a, branch.lastSon, comesFrom)
+  of nkCaseStmt:
+    for i in 1..<x.len:
+      let branch = x[i]
+      if branch.len > 0:
+        addRaiseEffectsFromExpr(a, branch.lastSon, comesFrom)
+  else:
+    addRaiseEffect(a, x, x)
+
 proc addTag(a: PEffects, e, comesFrom: PNode) =
   var aa = a.tags
   for i in 0..<aa.len:
@@ -1321,7 +1341,7 @@ proc track(tracked: PEffects, n: PNode) =
     if n[0].kind != nkEmpty:
       n[0].info = n.info
       #throws(tracked.exc, n[0])
-      addRaiseEffect(tracked, n[0], n)
+      addRaiseEffectsFromExpr(tracked, n[0], n)
       for i in 0..<n.safeLen:
         track(tracked, n[i])
       createTypeBoundOps(tracked, n[0].typ, n.info)
diff --git a/tests/effects/tcase_raises.nim b/tests/effects/tcase_raises.nim
new file mode 100644
index 0000000000..166a79d5c2
--- /dev/null
+++ b/tests/effects/tcase_raises.nim
@@ -0,0 +1,74 @@
+from std/os import osLastError, osErrorMsg, OSErrorCode, raiseOSError,
+                   newOSError, `==`
+
+{.push raises: [].}
+
+const
+  EPERM* = OSErrorCode(1)
+  ECONNABORTED* = OSErrorCode(53)
+  ETIMEDOUT* = OSErrorCode(60)
+  ENOTCONN* = OSErrorCode(107)
+  EMFILE* = OSErrorCode(24)
+  ENFILE* = OSErrorCode(23)
+  ENOBUFS* = OSErrorCode(55)
+  ENOMEM* = OSErrorCode(12)
+
+type
+  AsyncError* = object of CatchableError
+  TransportErrorBase* = object of AsyncError
+  TransportOsError* = object of TransportErrorBase
+    code*: OSErrorCode
+  TransportTooManyError* = object of TransportErrorBase
+  TransportAbortedError* = object of TransportErrorBase
+
+template getConnectionAbortedError*(
+           code: OSErrorCode
+         ): ref TransportAbortedError =
+  let msg =
+    case code
+    of OSErrorCode(0), ECONNABORTED:
+      "[ECONNABORTED] Connection has been aborted before being accepted"
+    of EPERM:
+      "[EPERM] Firewall rules forbid connection"
+    of ETIMEDOUT:
+      "[ETIMEDOUT] Operation has been timed out"
+    of ENOTCONN:
+      "[ENOTCONN] Transport endpoint is not connected"
+    else:
+      "[" & $int(code) & "] Connection has been aborted"
+  newException(TransportAbortedError, msg)
+
+template getTransportTooManyError*(
+           code = OSErrorCode(0)
+         ): ref TransportTooManyError =
+  let msg =
+    case code
+    of OSErrorCode(0):
+      "Too many open transports"
+    of EMFILE:
+      "[EMFILE] Too many open files in the process"
+    of ENFILE:
+      "[ENFILE] Too many open files in system"
+    of ENOBUFS:
+      "[ENOBUFS] No buffer space available"
+    of ENOMEM:
+      "[ENOMEM] Not enough memory availble"
+    else:
+      "[" & $int(code) & "] Too many open transports"
+  newException(TransportTooManyError, msg)
+
+template getTransportError*(ecode: OSErrorCode): untyped =
+  case ecode
+  of ECONNABORTED, EPERM, ETIMEDOUT, ENOTCONN:
+    getConnectionAbortedError(ecode)
+  of EMFILE, ENFILE, ENOBUFS, ENOMEM:
+    getTransportTooManyError(ecode)
+  else:
+    (ref TransportOsError)(code: ecode,
+                           msg: "(" & $int(ecode) & ") " & osErrorMsg(ecode))
+
+proc raiseTransportError*(err: OSErrorCode) {.
+     raises: [TransportAbortedError, TransportTooManyError, TransportOsError],
+     noreturn.} =
+  ## Raises transport specific OS error.
+  raise getTransportError(err)
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