[analyzer] Remove redundant check

[george.karpenkov]

Summary

There is no point in assigning void just to crash on it in the next line

[NoQ]

I'm in favor of changing this API into two overrides: one accepts TypedValueRegion, another accepts MemRegion and mandatory QualType. This does good job informing the caller of the problem.

lib/StaticAnalyzer/Core/RegionStore.cpp

   }
 
   if (!isa<TypedValueRegion>(MR)) {
     if (T.isNull()) {
       if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR))
         T = TR->getLocationType()->getPointeeType();
       else if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
         T = SR->getSymbol()->getType()->getPointeeType();
-      else if (isa<AllocaRegion>(MR))
-        T = Ctx.VoidTy;
     }
     assert(!T.isNull() && "Unable to auto-detect binding type!");
     assert(!T->isVoidType() && "Attempting to dereference a void pointer!");
     MR = GetElementZeroRegion(cast<SubRegion>(MR), T);
   }
 
   // FIXME: Perhaps this method should just take a 'const MemRegion*' argument
   //  instead of 'Loc', and have the other Loc cases handled at a higher level.