fixes getRtti, inheritance and nimChckNilDisp (#1086)

fixes `nimChckNilDisp` called for `var object`
fixes `getRtti` for `ptr` and `var` objects

Author: ringabout

src/hexer/lifter.nim

@@ -528,16 +528,23 @@ proc unravel(c: var LiftingCtx; typ: TypeCursor; paramA, paramB: TokenBuf) =
     let fn = lift(c, typ)
     maybeCallHook c, fn, paramA, paramB
 
+proc depth(s: SymId): int =
+  result = 0
+  var root = s
+  for r in inheritanceChain(s):
+    root = r
+    inc result
+
 proc setupVTableField(c: var LiftingCtx; param: TokenBuf; cls: SymId) =
   copyIntoKind c.dest, AsgnS, c.info:
     copyIntoKind c.dest, DotX, c.info:
       copyIntoKind c.dest, DerefX, c.info:
         copyTree c.dest, param
       copyIntoSymUse c.dest, pool.syms.getOrIncl(VTableField), c.info
-      c.dest.addIntLit(0, c.info)
+      c.dest.addIntLit(depth(cls), c.info)
     copyIntoKind c.dest, CallX, c.info:
       copyIntoSymUse c.dest, getCompilerProc(c, "getRtti"), c.info
-      copyIntoSymUse c.dest, cls, c.info
+      copyTree c.dest, param
 
 proc unravelDispatch(c: var LiftingCtx; orig: TypeCursor; paramA, paramB: TokenBuf) =
   #if isTrivial(c, typ):

src/hexer/vtables_backend.nim

@@ -103,7 +103,7 @@ proc evalOnce(c: var Context; dest: var TokenBuf; n: var Cursor): TempLoc =
     return result
 
   let info = n.info
-  let takeAddr = not constructsValue(n)
+  let takeAddr = not constructsValue(n) and n.exprKind notin {AddrX, HaddrX}
   let argType = getType(c.typeCache, n)
   c.needsXelim = true
 
@@ -191,7 +191,12 @@ proc trMethodCall(c: var Context; dest: var TokenBuf; n: var Cursor) =
   else:
     let info = n.info
     var temp = evalOnce(c, dest, n)
-    if typ.typeKind in {RefT, PtrT}:
+
+    var paramList = fnType
+    assert paramList.substructureKind == ParamsU
+    inc paramList
+    let param = takeLocal(paramList, SkipFinalParRi)
+    if param.typ.typeKind in {RefT, PtrT}:
       # nil check
       if not temp.needsParRi:
         c.needsXelim = true
@@ -242,10 +247,12 @@ proc trGetRtti(c: var Context; dest: var TokenBuf; n: var Cursor) =
   inc n # call
   skip n # skip "getRtti" symbol
   assert n.kind == Symbol # we have the class name here
-  let vtabName = getVTableName(c, n.symId)
+  let typ = getType(c.typeCache, n)
+  let cls = getClass(typ)
+  let vtabName = getVTableName(c, cls)
   dest.copyIntoKind AddrX, info:
     dest.addSymUse vtabName, info
-    maybeImport(c, n.symId, vtabName)
+    maybeImport(c, cls, vtabName)
   inc n
   skipParRi n
 
@@ -274,7 +281,7 @@ proc trCall(c: var Context; dest: var TokenBuf; n: var Cursor; forceStaticCall:
     dest.takeToken n # skip `(call)`
     trMethodCall c, dest, n
     takeParRi dest, n
-  elif n.kind == Symbol and n.symId == c.getRttiSym:
+  elif fn.kind == Symbol and fn.symId == c.getRttiSym:
     trGetRtti c, dest, n
   else:
     dest.takeToken n # skip `(call)`

tests/nimony/object/tmethods.nim

@@ -0,0 +1,31 @@
+import std/[assertions, syncio]
+
+type
+  TestObj = object of RootObj
+    t: int
+
+  SubObject = object of TestObj
+
+method test(t: ptr TestObj) {.base.} =
+  echo "test called"
+
+method test(t: ptr SubObject) =
+  t.t = 5
+
+block:
+  var a: SubObject = SubObject()
+
+  test(addr a)
+  assert a.t == 5
+
+method foo(t: var TestObj) {.base.} =
+  echo "test called"
+
+method foo(t: var SubObject) =
+  t.t = 5
+
+block:
+  var a: SubObject = SubObject()
+
+  foo(a)
+  assert a.t == 5