LoopConvert no longer take as alias references to other containers.

[angelgarcia]

Summary

Fix a bug where modernize-loop-convert check would take as alias a reference to other containers. Add the pertinent test.

[alexfh]

LG

clang-tidy/modernize/LoopConvertUtils.cpp

case Stmt::UnaryOperatorClass:
     return isDereferenceOfUop(cast<UnaryOperator>(Init), IndexVar);
 
   case Stmt::CXXOperatorCallExprClass: {
     const auto *OpCall = cast<CXXOperatorCallExpr>(Init);
     if (OpCall->getOperator() == OO_Star)
       return isDereferenceOfOpCall(OpCall, IndexVar);
     if (OpCall->getOperator() == OO_Subscript) {
       assert(OpCall->getNumArgs() == 2);
-      return true;
+      return isIndexInSubscriptExpr(OpCall->getArg(1), IndexVar);
     }
     break;
   }
 
   case Stmt::CXXMemberCallExprClass:
     return true;
 
   default:

test/clang-tidy/modernize-loop-convert-extra.cpp

for (S::iterator it = s.begin(), e = s.end(); it != e; ++it) {
     {}
     alias.x = 0;
   }
   // CHECK-MESSAGES: :[[@LINE-5]]:3: warning: use range-based for loop instead
   // CHECK-FIXES: for (auto & alias : s)
   // CHECK-FIXES-NOT: MutableVal &{{[a-z_]+}} =
   // CHECK-FIXES: {}
   // CHECK-FIXES-NEXT: alias.x = 0;
+
+  dependent<int> dep, other;
+  for (dependent<int>::iterator it = dep.begin(), e = dep.end(); it != e; ++it) {
+    printf("%d\n", *it);
+    const int& idx = other[0];
+  }
+  // CHECK-MESSAGES: :[[@LINE-4]]:3: warning: use range-based for loop instead
+  // CHECK-FIXES: for (auto & elem : dep)
+  // CHECK-FIXES-NEXT: printf("%d\n", elem);
+  // CHECK-FIXES-NEXT: const int& idx = other[0];
 }
 
 } // namespace NamingAlias
 
 namespace NamingConlict {
 
 #define MAX(a, b) (a > b) ? a : b
 #define DEF 5