--gc:destructors: next steps; WIP

lib/system.nim

@@ -1519,7 +1519,13 @@ when not defined(JS) and not defined(nimscript) and hostOS != "standalone":
 when not defined(JS) and not defined(nimscript) and hasAlloc and not defined(gcDestructors):
   proc addChar(s: NimString, c: char): NimString {.compilerProc, benign.}
 
-proc add*[T](x: var seq[T], y: T) {.magic: "AppendSeqElem", noSideEffect.}
+when defined(gcDestructors):
+  proc add*[T](x: var seq[T], y: sink T) {.magic: "AppendSeqElem", noSideEffect.} =
+    let xl = x.len
+    setLen(x, xl + 1)
+    x[xl] = y
+else:
+  proc add*[T](x: var seq[T], y: T) {.magic: "AppendSeqElem", noSideEffect.}
 proc add*[T](x: var seq[T], y: openArray[T]) {.noSideEffect.} =
   ## Generic proc for adding a data item `y` to a container `x`.
   ## For containers that have an order, `add` means *append*. New generic
@@ -3856,7 +3862,7 @@ proc shallow*(s: var string) {.noSideEffect, inline.} =
   ## marks a string `s` as `shallow`:idx:. Subsequent assignments will not
   ## perform deep copies of `s`. This is only useful for optimization
   ## purposes.
-  when not defined(JS) and not defined(nimscript):
+  when not defined(JS) and not defined(nimscript) and not defined(gcDestructors):
     var s = cast[PGenericSeq](s)
     # string literals cannot become 'shallow':
     if (s.reserved and strlitFlag) == 0:
@@ -4031,7 +4037,9 @@ proc locals*(): RootObj {.magic: "Plugin", noSideEffect.} =
   ##   # -> B is 1
   discard
 
-when hasAlloc and not defined(nimscript) and not defined(JS):
+when hasAlloc and not defined(nimscript) and not defined(JS) and
+    not defined(gcDestructors):
+  # XXX how to implement 'deepCopy' is an open problem.
   proc deepCopy*[T](x: var T, y: T) {.noSideEffect, magic: "DeepCopy".} =
     ## performs a deep copy of `y` and copies it into `x`.
     ## This is also used by the code generator

lib/system/repr.nim

@@ -25,24 +25,6 @@ proc reprPointer(x: pointer): string {.compilerproc.} =
     discard c_sprintf(buf, "%p", x)
     return $buf
 
-proc `$`(x: uint64): string =
-  if x == 0:
-    result = "0"
-  else:
-    result = newString(60)
-    var i = 0
-    var n = x
-    while n != 0:
-      let nn = n div 10'u64
-      result[i] = char(n - 10'u64 * nn + ord('0'))
-      inc i
-      n = nn
-    result.setLen i
-
-    let half = i div 2
-    # Reverse
-    for t in 0 .. half-1: swap(result[t], result[i-t-1])
-
 proc reprStrAux(result: var string, s: cstring; len: int) =
   if cast[pointer](s) == nil:
     add result, "nil"

lib/system/strmantle.nim

@@ -278,3 +278,21 @@ proc nimBoolToStr(x: bool): string {.compilerRtl.} =
 proc nimCharToStr(x: char): string {.compilerRtl.} =
   result = newString(1)
   result[0] = x
+
+proc `$`(x: uint64): string =
+  if x == 0:
+    result = "0"
+  else:
+    result = newString(60)
+    var i = 0
+    var n = x
+    while n != 0:
+      let nn = n div 10'u64
+      result[i] = char(n - 10'u64 * nn + ord('0'))
+      inc i
+      n = nn
+    result.setLen i
+
+    let half = i div 2
+    # Reverse
+    for t in 0 .. half-1: swap(result[t], result[i-t-1])