Fix #17199 (#17348)

* don't zero out in a move in the VM

* Add testcases for #17199

* Update tests/arc/tarcmisc.nim

Co-authored-by: Timothee Cour <timothee.cour2@gmail.com>

* Update tests/vm/tissues.nim

Co-authored-by: Timothee Cour <timothee.cour2@gmail.com>

* Fix test failures

* Fix test

* Fix tests

Co-authored-by: Andreas Rumpf <rumpf_a@web.de>
Co-authored-by: Timothee Cour <timothee.cour2@gmail.com>

compiler/vmgen.nim

@@ -1354,9 +1354,10 @@ proc genMagic(c: PCtx; n: PNode; dest: var TDest; m: TMagic) =
     if dest < 0: dest = c.getTemp(arg.typ)
     gABC(c, arg, whichAsgnOpc(arg, requiresCopy=false), dest, a)
     # XXX use ldNullOpcode() here?
-    c.gABx(n, opcLdNull, a, c.genType(arg.typ))
-    c.gABx(n, opcNodeToReg, a, a)
-    c.genAsgnPatch(arg, a)
+    # Don't zero out the arg for now #17199
+    # c.gABx(n, opcLdNull, a, c.genType(arg.typ))
+    # c.gABx(n, opcNodeToReg, a, a)
+    # c.genAsgnPatch(arg, a)
     c.freeTemp(a)
   of mNodeId:
     c.genUnaryABC(n, dest, opcNodeId)

tests/arc/tarcmisc.nim

@@ -390,3 +390,35 @@ proc newPixelBuffer(): PixelBuffer =
 
 discard newPixelBuffer()
 
+
+# bug #17199
+
+proc passSeq(data: seq[string]) =
+  # used the system.& proc initially
+  let wat = data & "hello"
+
+proc test2 =
+  let name = @["hello", "world"]
+  passSeq(name)
+  doAssert name == @["hello", "world"]
+
+static: test2() # was buggy
+test2()
+
+proc merge(x: sink seq[string], y: sink string): seq[string] =
+  newSeq(result, x.len + 1)
+  for i in 0..x.len-1:
+    result[i] = move(x[i])
+  result[x.len] = move(y)
+
+proc passSeq2(data: seq[string]) =
+  # used the system.& proc initially
+  let wat = merge(data, "hello")
+
+proc test3 =
+  let name = @["hello", "world"]
+  passSeq2(name)
+  doAssert name == @["hello", "world"]
+
+static: test3() # was buggy
+test3()

tests/stdlib/tisolation.nim

@@ -7,7 +7,7 @@ import std/[isolation, json]
 
 
 
-proc main() =
+proc main(moveZeroesOut: static bool) =
   block:
     type
       Empty = ref object
@@ -19,64 +19,76 @@ proc main() =
   block: # string literals
     var data = isolate("string")
     doAssert data.extract == "string"
-    doAssert data.extract == ""
+    if moveZeroesOut:
+      doAssert data.extract == ""
 
   block: # string literals
     var data = isolate("")
     doAssert data.extract == ""
-    doAssert data.extract == ""
+    if moveZeroesOut:
+      doAssert data.extract == ""
 
   block:
     var src = "string"
     var data = isolate(move src)
     doAssert data.extract == "string"
-    doAssert src.len == 0
+    if moveZeroesOut:
+      doAssert src.len == 0
 
   block: # int literals
     var data = isolate(1)
     doAssert data.extract == 1
-    doAssert data.extract == 0
+    if moveZeroesOut:
+      doAssert data.extract == 0
 
   block: # float literals
     var data = isolate(1.6)
     doAssert data.extract == 1.6
-    doAssert data.extract == 0.0
+    if moveZeroesOut:
+      doAssert data.extract == 0.0
 
   block:
     var data = isolate(@["1", "2"])
     doAssert data.extract == @["1", "2"]
-    doAssert data.extract == @[]
+    if moveZeroesOut:
+      doAssert data.extract == @[]
 
   block:
     var data = isolate(@["1", "2", "3", "4", "5"])
     doAssert data.extract == @["1", "2", "3", "4", "5"]
-    doAssert data.extract == @[]
+    if moveZeroesOut:
+      doAssert data.extract == @[]
 
   block:
     var data = isolate(@["", ""])
     doAssert data.extract == @["", ""]
-    doAssert data.extract == @[]
+    if moveZeroesOut:
+      doAssert data.extract == @[]
 
   block:
     var src = @["1", "2"]
     var data = isolate(move src)
     doAssert data.extract == @["1", "2"]
-    doAssert src.len == 0
+    if moveZeroesOut:
+      doAssert src.len == 0
 
   block:
     var data = isolate(@[1, 2])
     doAssert data.extract == @[1, 2]
-    doAssert data.extract == @[]
+    if moveZeroesOut:
+      doAssert data.extract == @[]
 
   block:
     var data = isolate(["1", "2"])
     doAssert data.extract == ["1", "2"]
-    doAssert data.extract == ["", ""]
+    if moveZeroesOut:
+      doAssert data.extract == ["", ""]
 
   block:
     var data = isolate([1, 2])
     doAssert data.extract == [1, 2]
-    doAssert data.extract == [0, 0]
+    if moveZeroesOut:
+      doAssert data.extract == [0, 0]
 
   block:
     type
@@ -119,5 +131,5 @@ proc main() =
     doAssert $x == """@[(value: "1234")]"""
 
 
-static: main()
-main()
+static: main(moveZeroesOut = false)
+main(moveZeroesOut = true)