fixes #24476; remove proc type cast if they are same types for backends (#24480)

fixes #24476

closes https://github.com/nim-lang/Nim/pull/24479

(cherry picked from commit 5340005869)

compiler/ccgexprs.nim

@@ -2159,6 +2159,8 @@ proc genSomeCast(p: BProc, e: PNode, d: var TLoc) =
           [getTypeDesc(p.module, e.typ), rdCharLoc(a)], a.storage)
     elif etyp.kind == tyBool and srcTyp.kind in IntegralTypes:
       putIntoDest(p, d, e, "(($1) != 0)" % [rdCharLoc(a)], a.storage)
+    elif etyp.kind == tyProc and srcTyp.kind == tyProc and sameBackendType(etyp, srcTyp):
+      expr(p, e[1], d)
     else:
       if etyp.kind == tyPtr:
         # generates the definition of structs for casts like cast[ptr object](addr x)[]

compiler/vtables.nim

@@ -15,7 +15,6 @@ proc dispatch(x: Base, params: ...) =
 
   var disp = newNodeI(nkIfStmt, base.info)
 
-  var vTableAccess = newNodeIT(nkBracketExpr, base.info, base.typ)
   let nimGetVTableSym = getCompilerProc(g, "nimGetVTable")
   let ptrPNimType = nimGetVTableSym.typ.n[1].sym.typ
 
@@ -33,7 +32,7 @@ proc dispatch(x: Base, params: ...) =
     dispatchObject,
     newIntNode(nkIntLit, index)
   )
-  getVTableCall.typ() = base.typ
+  getVTableCall.typ() = getSysType(g, unknownLineInfo, tyPointer)
   var vTableCall = newNodeIT(nkCall, base.info, base.typ.returnType)
   var castNode = newTree(nkCast,
         newNodeIT(nkType, base.info, base.typ),