7 files changed, 19 insertions, 23 deletions
diff --git a/lib/pure/dynlib.nim b/lib/pure/dynlib.nim
index d030ad532..97bc51bc5 100644
--- a/lib/pure/dynlib.nim
+++ b/lib/pure/dynlib.nim
@@ -72,10 +72,7 @@ proc unloadLib*(lib: LibHandle) {.gcsafe.}
 
 proc raiseInvalidLibrary*(name: cstring) {.noinline, noreturn.} =
   ## raises an `EInvalidLibrary` exception.
-  var e: ref LibraryError
-  new(e)
-  e.msg = "could not find symbol: " & $name
-  raise e
+  raise newException(LibraryError, "could not find symbol: " & $name)
 
 proc symAddr*(lib: LibHandle, name: cstring): pointer {.gcsafe.}
   ## retrieves the address of a procedure/variable from `lib`. Returns nil
diff --git a/lib/pure/includes/oserr.nim b/lib/pure/includes/oserr.nim
index 25e221d3b..947bdd9a9 100644
--- a/lib/pure/includes/oserr.nim
+++ b/lib/pure/includes/oserr.nim
@@ -73,7 +73,7 @@ proc raiseOSError*(errorCode: OSErrorCode; additionalInfo = "") {.noinline.} =
   ## See also:
   ## * `osErrorMsg proc <#osErrorMsg,OSErrorCode>`_
   ## * `osLastError proc <#osLastError>`_
-  var e: ref OSError; new(e)
+  var e: owned(ref OSError); new(e)
   e.errorCode = errorCode.int32
   e.msg = osErrorMsg(errorCode)
   if additionalInfo.len > 0:
diff --git a/lib/pure/osproc.nim b/lib/pure/osproc.nim
index af0e2e782..1888df813 100644
--- a/lib/pure/osproc.nim
+++ b/lib/pure/osproc.nim
@@ -126,7 +126,7 @@ proc startProcess*(command: string,
                    args: openArray[string] = [],
                    env: StringTableRef = nil,
                    options: set[ProcessOption] = {poStdErrToStdOut}):
-              Process {.rtl, extern: "nosp$1", tags: [ExecIOEffect, ReadEnvEffect,
+              owned Process {.rtl, extern: "nosp$1", tags: [ExecIOEffect, ReadEnvEffect,
               RootEffect].}
   ## Starts a process. `Command` is the executable file, `workingDir` is the
   ## process's working directory. If ``workingDir == ""`` the current directory
@@ -470,7 +470,7 @@ when defined(Windows) and not defined(useNimRtl):
                               addr bytesWritten, nil)
     if a == 0: raiseOSError(osLastError())
 
-  proc newFileHandleStream(handle: Handle): FileHandleStream =
+  proc newFileHandleStream(handle: Handle): owned FileHandleStream =
     new(result)
     result.handle = handle
     result.closeImpl = hsClose
@@ -573,7 +573,7 @@ when defined(Windows) and not defined(useNimRtl):
                  workingDir: string = "",
                  args: openArray[string] = [],
                  env: StringTableRef = nil,
-                 options: set[ProcessOption] = {poStdErrToStdOut}): Process =
+                 options: set[ProcessOption] = {poStdErrToStdOut}): owned Process =
     var
       si: STARTUPINFO
       procInfo: PROCESS_INFORMATION
@@ -840,7 +840,7 @@ elif not defined(useNimRtl):
                  workingDir: string = "",
                  args: openArray[string] = [],
                  env: StringTableRef = nil,
-                 options: set[ProcessOption] = {poStdErrToStdOut}): Process =
+                 options: set[ProcessOption] = {poStdErrToStdOut}): owned Process =
     var
       pStdin, pStdout, pStderr: array[0..1, cint]
     new(result)
diff --git a/lib/pure/streams.nim b/lib/pure/streams.nim
index 6c69a9bb6..ff2b72725 100644
--- a/lib/pure/streams.nim
+++ b/lib/pure/streams.nim
@@ -34,7 +34,7 @@
 
 include "system/inclrtl"
 
-proc newEIO(msg: string): ref IOError =
+proc newEIO(msg: string): owned(ref IOError) =
   new(result)
   result.msg = msg
 
@@ -403,7 +403,7 @@ when not defined(js):
     else:
       s.data = nil
 
-  proc newStringStream*(s: string = ""): StringStream =
+  proc newStringStream*(s: string = ""): owned StringStream =
     ## creates a new stream from the string `s`.
     new(result)
     result.data = s
@@ -446,7 +446,7 @@ when not defined(js):
     if writeBuffer(FileStream(s).f, buffer, bufLen) != bufLen:
       raise newEIO("cannot write to stream")
 
-  proc newFileStream*(f: File): FileStream =
+  proc newFileStream*(f: File): owned FileStream =
     ## creates a new stream from the file `f`.
     new(result)
     result.f = f
@@ -460,7 +460,7 @@ when not defined(js):
     result.writeDataImpl = fsWriteData
     result.flushImpl = fsFlush
 
-  proc newFileStream*(filename: string, mode: FileMode = fmRead, bufSize: int = -1): FileStream =
+  proc newFileStream*(filename: string, mode: FileMode = fmRead, bufSize: int = -1): owned FileStream =
     ## creates a new stream from the file named `filename` with the mode `mode`.
     ## If the file cannot be opened, nil is returned. See the `system
     ## <system.html>`_ module for a list of available FileMode enums.
@@ -469,7 +469,7 @@ when not defined(js):
     var f: File
     if open(f, filename, mode, bufSize): result = newFileStream(f)
 
-  proc openFileStream*(filename: string, mode: FileMode = fmRead, bufSize: int = -1): FileStream =
+  proc openFileStream*(filename: string, mode: FileMode = fmRead, bufSize: int = -1): owned FileStream =
     ## creates a new stream from the file named `filename` with the mode `mode`.
     ## If the file cannot be opened, an IO exception is raised.
     var f: File
@@ -522,7 +522,7 @@ else:
         raise newEIO("cannot write to stream")
       inc(s.pos, bufLen)
 
-  proc newFileHandleStream*(handle: FileHandle): FileHandleStream =
+  proc newFileHandleStream*(handle: FileHandle): owned FileHandleStream =
     new(result)
     result.handle = handle
     result.pos = 0
@@ -535,7 +535,7 @@ else:
     result.writeData = hsWriteData
 
   proc newFileHandleStream*(filename: string,
-                            mode: FileMode): FileHandleStream =
+                            mode: FileMode): owned FileHandleStream =
     when defined(windows):
       discard
     else:
diff --git a/lib/pure/strtabs.nim b/lib/pure/strtabs.nim
index 2568f83c2..f158bb2fc 100644
--- a/lib/pure/strtabs.nim
+++ b/lib/pure/strtabs.nim
@@ -247,7 +247,7 @@ proc `[]=`*(t: StringTableRef, key, val: string) {.
     rawInsert(t, t.data, key, val)
     inc(t.counter)
 
-proc newStringTable*(mode: StringTableMode): StringTableRef {.
+proc newStringTable*(mode: StringTableMode): owned StringTableRef {.
   rtlFunc, extern: "nst$1".} =
   ## Creates a new empty string table.
   ##
@@ -260,7 +260,7 @@ proc newStringTable*(mode: StringTableMode): StringTableRef {.
   newSeq(result.data, startSize)
 
 proc newStringTable*(keyValuePairs: varargs[string],
-                     mode: StringTableMode): StringTableRef {.
+                     mode: StringTableMode): owned StringTableRef {.
   rtlFunc, extern: "nst$1WithPairs".} =
   ## Creates a new string table with given `key, value` string pairs.
   ##
@@ -290,10 +290,7 @@ proc newStringTable*(keyValuePairs: varargs[tuple[key, val: string]],
   for key, val in items(keyValuePairs): result[key] = val
 
 proc raiseFormatException(s: string) =
-  var e: ref ValueError
-  new(e)
-  e.msg = "format string: key not found: " & s
-  raise e
+  raise newException(ValueError, "format string: key not found: " & s)
 
 proc getValue(t: StringTableRef, flags: set[FormatFlag], key: string): string =
   if hasKey(t, key): return t.getOrDefault(key)
diff --git a/lib/pure/times.nim b/lib/pure/times.nim
index 1bb23a311..5fd57c843 100644
--- a/lib/pure/times.nim
+++ b/lib/pure/times.nim
@@ -959,7 +959,7 @@ proc newTimezone*(
           {.tags: [], raises: [], benign.},
       zonedTimeFromAdjTimeImpl: proc (adjTime: Time): ZonedTime
           {.tags: [], raises: [], benign.}
-    ): Timezone =
+    ): owned Timezone =
   ## Create a new ``Timezone``.
   ##
   ## ``zonedTimeFromTimeImpl`` and ``zonedTimeFromAdjTimeImpl`` is used
diff --git a/lib/system.nim b/lib/system.nim
index c0f32961b..7bd3aa625 100644
--- a/lib/system.nim
+++ b/lib/system.nim
@@ -1638,6 +1638,8 @@ when defined(nimV2) and not defined(nimscript):
     new(r)
     return r
 else:
+  template owned*(t: typeDesc): typedesc = t
+
   proc new*[T](a: var ref T) {.magic: "New", noSideEffect.}
     ## Creates a new object of type ``T`` and returns a safe (traced)
     ## reference to it in ``a``.