diff --git a/compiler/ccgtypes.nim b/compiler/ccgtypes.nim
index fafc19210e..b5ecee5da0 100755
--- a/compiler/ccgtypes.nim
+++ b/compiler/ccgtypes.nim
@@ -531,7 +531,9 @@ proc genProcHeader(m: BModule, prc: PSym): PRope =
   var check = initIntSet()
   fillLoc(prc.loc, locProc, prc.typ, mangleName(prc), OnUnknown)
   genProcParams(m, prc.typ, rettype, params, check)
-  genCLineDir(result, prc.ast.sons[codePos])
+  # careful here! don't access ``prc.ast`` as that could reload large parts of
+  # the object graph!
+  genCLineDir(result, prc.info)
   appf(result, "$1($2, $3)$4", 
        [toRope(CallingConvToStr[prc.typ.callConv]), rettype, prc.loc.r, params])
 
diff --git a/compiler/cgen.nim b/compiler/cgen.nim
index 51d6f2f849..a5343e3f7b 100755
--- a/compiler/cgen.nim
+++ b/compiler/cgen.nim
@@ -148,9 +148,9 @@ proc appcg(p: BProc, s: TCProcSection, frmt: TFormatStr,
            args: openarray[PRope]) = 
   app(p.s[s], ropecg(p.module, frmt, args))
 
-proc safeLineNm(t: PNode) : int =
-  result = toLinenumber(t.info)   # BUGFIX
-  if result < 0: result = 0       # negative numbers are not allowed in #line
+proc safeLineNm(info: TLineInfo): int =
+  result = toLinenumber(info)
+  if result < 0: result = 0 # negative numbers are not allowed in #line
 
 proc genCLineDir(r: var PRope, filename: string, line: int) =
   assert line >= 0
@@ -158,11 +158,11 @@ proc genCLineDir(r: var PRope, filename: string, line: int) =
     appff(r, "$N#line $2 $1$N", "; line $2 \"$1\"$n",
           [toRope(makeSingleLineCString(filename)), toRope(line)])
 
-proc genCLineDir(r: var PRope, t: PNode) = 
-  genCLineDir(r, t.info.toFullPath, t.safeLineNm)
+proc genCLineDir(r: var PRope, info: TLineInfo) = 
+  genCLineDir(r, info.toFullPath, info.safeLineNm)
 
 proc genLineDir(p: BProc, t: PNode) = 
-  var line = t.safeLineNm
+  var line = t.info.safeLineNm
   genCLineDir(p.s[cpsStmts], t.info.toFullPath, line)
   if ({optStackTrace, optEndb} * p.Options == {optStackTrace, optEndb}) and
       (p.prc == nil or sfPure notin p.prc.flags): 
@@ -447,7 +447,6 @@ proc SymInDynamicLib(m: BModule, sym: PSym) =
   var lib = sym.annex
   var extname = sym.loc.r
   loadDynamicLib(m, lib)
-  #discard cgsym(m, "nimGetProcAddr")
   if gCmd == cmdCompileToLLVM: incl(sym.loc.flags, lfIndirect)
   var tmp = mangleDynLibProc(sym)
   sym.loc.r = tmp             # from now on we only need the internal name
@@ -461,6 +460,10 @@ proc SymInDynamicLib(m: BModule, sym: PSym) =
       "$1 = linkonce global $2 zeroinitializer$n", 
       [sym.loc.r, getTypeDesc(m, sym.loc.t)])
 
+proc SymInDynamicLibPartial(m: BModule, sym: PSym) =
+  sym.loc.r = mangleDynLibProc(sym)
+  sym.typ.sym = nil           # generate a new name
+
 proc cgsym(m: BModule, name: string): PRope = 
   var sym = magicsys.getCompilerProc(name)
   if sym != nil: 
@@ -583,7 +586,7 @@ proc genProcAux(m: BModule, prc: PSym) =
 proc genProcPrototype(m: BModule, sym: PSym) = 
   useHeader(m, sym)
   if lfNoDecl in sym.loc.Flags: return 
-  if lfDynamicLib in sym.loc.Flags: 
+  if lfDynamicLib in sym.loc.Flags:
     if sym.owner.id != m.module.id and
         not ContainsOrIncl(m.declaredThings, sym.id): 
       appf(m.s[cfsVars], "extern $1 $2;$n", 
@@ -610,6 +613,8 @@ proc genProcNoForward(m: BModule, prc: PSym) =
     var q = findPendingModule(m, prc)
     if q != nil and not ContainsOrIncl(q.declaredThings, prc.id): 
       SymInDynamicLib(q, prc)
+    else:
+      SymInDynamicLibPartial(m, prc)
   elif sfImportc notin prc.flags:
     var q = findPendingModule(m, prc)
     if q != nil and not ContainsOrIncl(q.declaredThings, prc.id): 
diff --git a/compiler/extccomp.nim b/compiler/extccomp.nim
index b48c65f872..485ccc7d48 100755
--- a/compiler/extccomp.nim
+++ b/compiler/extccomp.nim
@@ -334,7 +334,7 @@ proc addFileToLink*(filename: string) =
   # BUGFIX: was ``appendStr``
 
 proc execExternalProgram*(cmd: string) = 
-  if (optListCmd in gGlobalOptions) or (gVerbosity > 0): MsgWriteln(cmd)
+  if optListCmd in gGlobalOptions or gVerbosity > 0: MsgWriteln(cmd)
   if execCmd(cmd) != 0: rawMessage(errExecutionOfProgramFailed, "")
 
 proc generateScript(projectFile: string, script: PRope) = 
diff --git a/compiler/types.nim b/compiler/types.nim
index 7c88e23352..9d5d12b06b 100755
--- a/compiler/types.nim
+++ b/compiler/types.nim
@@ -70,11 +70,6 @@ proc getOrdValue*(n: PNode): biggestInt
 proc computeSize*(typ: PType): biggestInt
 proc getSize*(typ: PType): biggestInt
 proc isPureObject*(typ: PType): bool
-proc inheritanceDiff*(a, b: PType): int
-  # | returns: 0 iff `a` == `b`
-  # | returns: -x iff `a` is the x'th direct superclass of `b`
-  # | returns: +x iff `a` is the x'th direct subclass of `b`
-  # | returns: `maxint` iff `a` and `b` are not compatible at all
 proc InvalidGenericInst*(f: PType): bool
   # for debugging
 type 
@@ -93,22 +88,6 @@ proc typeAllowed*(t: PType, kind: TSymKind): bool
 proc InvalidGenericInst(f: PType): bool = 
   result = (f.kind == tyGenericInst) and (lastSon(f) == nil)
 
-proc inheritanceDiff(a, b: PType): int = 
-  # conversion to superclass?
-  var x = a
-  result = 0
-  while x != nil: 
-    if x.id == b.id: return 
-    x = x.sons[0]
-    dec(result)
-  var y = b
-  result = 0
-  while y != nil: 
-    if y.id == a.id: return 
-    y = y.sons[0]
-    inc(result)
-  result = high(int)
-
 proc isPureObject(typ: PType): bool = 
   var t = typ
   while t.sons[0] != nil: t = t.sons[0]
@@ -553,24 +532,19 @@ type
 
   TSameTypeClosure = object {.pure.}
     cmp: TDistinctCompare
-    initSets: bool
     recCheck: int
-    a: TIntSet
-    b: TIntSet
+    s: seq[tuple[a,b: int]] # seq for a set as it's hopefully faster
+                            # (few elements expected)
 
 proc initSameTypeClosure: TSameTypeClosure =
   # we do the initialization lazy for performance (avoids memory allocations)
   nil
 
 proc containsOrIncl(c: var TSameTypeClosure, a, b: PType): bool =
-  result = c.initSets and c.a.contains(a.id) and c.b.contains(b.id)
+  result = not IsNil(c.s) and c.s.contains((a.id, b.id))
   if not result:
-    if not c.initSets:
-      c.initSets = true
-      c.a = initIntSet()
-      c.b = initIntSet()
-    c.a.incl(a.id)
-    c.b.incl(b.id)
+    if IsNil(c.s): c.s = @[]
+    c.s.add((a.id, b.id))
 
 proc SameTypeAux(x, y: PType, c: var TSameTypeClosure): bool
 proc SameTypeOrNilAux(a, b: PType, c: var TSameTypeClosure): bool =
@@ -731,7 +705,7 @@ proc SameTypeAux(x, y: PType, c: var TSameTypeClosure): bool =
     # again: Since the recursion check is only to not get caught in an endless
     # recursion, we use a counter and only if it's value is over some 
     # threshold we perform the expansive exact cycle check:
-    if c.recCheck < 20:
+    if c.recCheck < 3:
       inc c.recCheck
     else:
       if containsOrIncl(c, a, b): return true
@@ -797,6 +771,25 @@ proc compareTypes*(x, y: PType, cmp: TDistinctCompare): bool =
   c.cmp = cmp
   result = sameTypeAux(x, y, c)
   
+proc inheritanceDiff*(a, b: PType): int = 
+  # | returns: 0 iff `a` == `b`
+  # | returns: -x iff `a` is the x'th direct superclass of `b`
+  # | returns: +x iff `a` is the x'th direct subclass of `b`
+  # | returns: `maxint` iff `a` and `b` are not compatible at all
+  var x = a
+  result = 0
+  while x != nil:
+    if sameObjectTypes(x, b): return 
+    x = x.sons[0]
+    dec(result)
+  var y = b
+  result = 0
+  while y != nil:
+    if sameObjectTypes(y, a): return 
+    y = y.sons[0]
+    inc(result)
+  result = high(int)
+    
 proc typeAllowedAux(marker: var TIntSet, typ: PType, kind: TSymKind): bool
 proc typeAllowedNode(marker: var TIntSet, n: PNode, kind: TSymKind): bool = 
   result = true
diff --git a/todo.txt b/todo.txt
index 8e12797bbe..84543fae9e 100755
--- a/todo.txt
+++ b/todo.txt
@@ -16,7 +16,6 @@ Version 0.8.14
 incremental compilation
 -----------------------
 
-- fix DLL interfacing!
 - the loading has to be MUCH more lazy! --> next version: We should re-load
   symbol.ast lazily
 - adapt thread var implementation to care about the new merge operation
@@ -28,6 +27,7 @@ incremental compilation
   - test type converters
   - test G, A, B example from the documentation; test init sections
   - test method generation
+  - test DLL interfacing
 
 
 version 0.9.0
@@ -35,7 +35,7 @@ version 0.9.0
 
 - test the sort implementation again
 - const ptr/ref
-- unsigned ints and bignums
+- unsigned ints and bignums; requires abstract integer literal type
 - implement the high level optimizer
 - warning for implicit openArray -> varargs convention
 - implement explicit varargs