From 2977a316542ee71f31aaedcc38eb0494f2f5ff23 Mon Sep 17 00:00:00 2001
From: Andreas Rumpf <rumpf_a@web.de>
Date: Mon, 4 May 2020 07:43:22 +0200
Subject: [PATCH] destructors: don't produce stupid code for 'cast' (#14208)
 [backport:1.2]

* destructors: don't produce stupid code for 'cast'

* fixes #14207

(cherry picked from commit b6fb609e0d263a209c6db48dd367f13eb7f4ff87)
---
 compiler/dfa.nim               |  4 ++--
 compiler/injectdestructors.nim |  4 ++++
 tests/arc/tarcmisc.nim         | 14 ++++++++++++++
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/compiler/dfa.nim b/compiler/dfa.nim
index 0cefec2858d1d..7db5f5f65af50 100644
--- a/compiler/dfa.nim
+++ b/compiler/dfa.nim
@@ -541,8 +541,8 @@ template genNoReturn(c: var Con; n: PNode) =
   c.code.add Instr(n: n, kind: goto, dest: high(int) - c.code.len)
 
 proc genRaise(c: var Con; n: PNode) =
-  genJoins(c, n)
   gen(c, n[0])
+  genJoins(c, n)
   if c.inTryStmt > 0:
     c.tryStmtFixups.add c.gotoI(n)
   else:
@@ -553,11 +553,11 @@ proc genImplicitReturn(c: var Con) =
     gen(c, c.owner.ast[resultPos])
 
 proc genReturn(c: var Con; n: PNode) =
-  genJoins(c, n)
   if n[0].kind != nkEmpty:
     gen(c, n[0])
   else:
     genImplicitReturn(c)
+  genJoins(c, n)
   genNoReturn(c, n)
 
 const
diff --git a/compiler/injectdestructors.nim b/compiler/injectdestructors.nim
index 29199aa415b44..5aec088aa4bda 100644
--- a/compiler/injectdestructors.nim
+++ b/compiler/injectdestructors.nim
@@ -910,6 +910,10 @@ proc p(n: PNode; c: var Con; mode: ProcessMode): PNode =
       for i in 0..<n.len:
         result[i] = p(n[i], c, mode)
       inc c.hasUnstructuredCf
+    of nkCast:
+      result = shallowCopy(n)
+      result[0] = n[0]
+      result[1] = p(n[1], c, mode)
     else:
       result = shallowCopy(n)
       for i in 0..<n.len:
diff --git a/tests/arc/tarcmisc.nim b/tests/arc/tarcmisc.nim
index ce8e902c6b1ca..c0583a64045ac 100644
--- a/tests/arc/tarcmisc.nim
+++ b/tests/arc/tarcmisc.nim
@@ -1,5 +1,6 @@
 discard """
   output: '''
+123xyzabc
 destroyed: false
 destroyed: false
 closed
@@ -8,6 +9,19 @@ destroying variable
   cmd: "nim c --gc:arc $file"
 """
 
+proc takeSink(x: sink string): bool = true
+
+proc b(x: sink string): string =
+  if takeSink(x):
+    return x & "abc"
+
+proc bbb(inp: string) =
+  let y = inp & "xyz"
+  echo b(y)
+
+bbb("123")
+
+
 # bug #13691
 type Variable = ref object
   value: int