diff --git a/compiler/semexprs.nim b/compiler/semexprs.nim
index 73e92ab75..9e3e5e076 100644
--- a/compiler/semexprs.nim
+++ b/compiler/semexprs.nim
@@ -1522,7 +1522,7 @@ proc asgnToResultVar(c: PContext, n, le, ri: PNode) {.inline.} =
 proc asgnToResult(c: PContext, n, le, ri: PNode) =
   # Special typing rule: do not allow to pass 'owned T' to 'T' in 'result = x':
   if ri.typ != nil and ri.typ.skipTypes(abstractInst).kind == tyOwned and
-      le.typ != nil and le.typ.skipTypes(abstractInst).kind != tyOwned:
+      le.typ != nil and le.typ.skipTypes(abstractInst).kind != tyOwned and ri.kind in nkCallKinds:
     localError(c.config, n.info, "cannot return an owned pointer as an unowned pointer; " &
       "use 'owned(" & typeToString(le.typ) & ")' as the return type")
 
diff --git a/lib/pure/osproc.nim b/lib/pure/osproc.nim
index 88df65aa9..0cdc3583d 100644
--- a/lib/pure/osproc.nim
+++ b/lib/pure/osproc.nim
@@ -57,8 +57,8 @@ type
       id: Handle
     else:
       inHandle, outHandle, errHandle: FileHandle
-      inStream, outStream, errStream: Stream
       id: Pid
+    inStream, outStream, errStream: owned(Stream)
     exitStatus: cint
     exitFlag: bool
     options: set[ProcessOption]
@@ -724,15 +724,21 @@ when defined(Windows) and not defined(useNimRtl):
 
   proc inputStream(p: Process): Stream =
     streamAccess(p)
-    result = newFileHandleStream(p.inHandle)
+    if p.inStream == nil:
+      p.inStream = newFileHandleStream(p.inHandle)
+    result = p.inStream
 
   proc outputStream(p: Process): Stream =
     streamAccess(p)
-    result = newFileHandleStream(p.outHandle)
+    if p.outStream == nil:
+      p.outStream = newFileHandleStream(p.outHandle)
+    result = p.outStream
 
   proc errorStream(p: Process): Stream =
     streamAccess(p)
-    result = newFileHandleStream(p.errHandle)
+    if p.errStream == nil:
+      p.errStream = newFileHandleStream(p.errHandle)
+    result = p.errStream
 
   proc execCmd(command: string): int =
     var
diff --git a/lib/pure/strtabs.nim b/lib/pure/strtabs.nim
index 269fe11f7..0726eb15d 100644
--- a/lib/pure/strtabs.nim
+++ b/lib/pure/strtabs.nim
@@ -276,7 +276,7 @@ proc newStringTable*(keyValuePairs: varargs[string],
     inc(i, 2)
 
 proc newStringTable*(keyValuePairs: varargs[tuple[key, val: string]],
-                     mode: StringTableMode = modeCaseSensitive): StringTableRef {.
+                     mode: StringTableMode = modeCaseSensitive): owned(StringTableRef) {.
   rtlFunc, extern: "nst$1WithTableConstr".} =
   ## Creates a new string table with given `(key, value)` tuple pairs.
   ##