tests/gc/gcleak4.nim

doc/tut2.txt

@@ -558,10 +558,10 @@ The template body does not open a new scope. To open a new scope use a ``block``
 statement:
 
 .. code-block:: nimrod
-  template declareInScope(x: expr, t: typeDesc): stmt =
+  template declareInScope(x: expr, t: typeDesc): stmt {.immediate.} =
     var x: t
 
-  template declareInNewScope(x: expr, t: typeDesc): stmt =
+  template declareInNewScope(x: expr, t: typeDesc): stmt {.immediate.} =
     # open a new scope:
     block:
       var x: t
@@ -572,6 +572,8 @@ statement:
   declareInNewScope(b, int)
   b = 42  # does not work, `b` is unknown
 
+(The manual explains why the ``immediate`` pragma is needed for these 
+templates.)
 
 If there is a ``stmt`` parameter it should be the last in the template
 declaration. The reason is that statements can be passed to a template
@@ -580,7 +582,7 @@ via a special ``:`` syntax:
 .. code-block:: nimrod
 
   template withFile(f: expr, filename: string, mode: TFileMode,
-                    body: stmt): stmt =
+                    body: stmt): stmt {.immediate.} =
     block:
       let fn = filename
       var f: TFile

lib/system/debugger.nim

@@ -632,7 +632,12 @@ proc genericHashAux(dest: Pointer, mt: PNimType, shallow: bool,
     else:
       result = h
       var s = cast[ppointer](dest)[]
-      if s != nil: result = genericHashAux(s, mt.base, shallow, result)
+      if s != nil:
+        result = result !& genericHashAux(s, mt.base, shallow, result)
+        # hash the object header:
+        #const headerSize = sizeof(int)*2
+        #result = result !& hash(cast[pointer](cast[int](s) -% headerSize),
+        #                        headerSize)
   else:
     result = h !& hash(dest, mt.size) # hash raw bits
 

lib/system/gc.nim

@@ -100,6 +100,8 @@ proc usrToCell(usr: pointer): PCell {.inline.} =
   result = cast[PCell](cast[TAddress](usr)-%TAddress(sizeof(TCell)))
 
 proc canbeCycleRoot(c: PCell): bool {.inline.} =
+  if c.typ == nil:
+    echo "ARRGHHHHHHH"
   result = ntfAcyclic notin c.typ.flags
 
 proc extGetCellType(c: pointer): PNimType {.compilerproc.} =