Reference to 'X' Is Ambiguous

Reference to 'X' is ambiguous

Ok after creating a new Project and coping everything to this project the build was successful however i got this "Malformed or corrupted AST file" error several times again but it can be solved by:

Clean the project
Deleting everything inside '~/Library/Developer/Xcode/DerivedData/ModuleCache/' (the button inside the organizer window did not work for me)
Clean once more
Build project

after that it works just fine except that i have to do this fix from time to time

i also did a diff to the old project and it seems a lot of frameworks and other old stuff got stuck in there from testing things so in case you have this check your project settings file for old stuff.

i thought that xcode and me can be friends one day. guess not...

Why did I get rid of an error (reference to is ambiguous) just by removing using namespace std; in c++?

This is because left is the manipulator defined in C++ under namespace std.As,you are using it in your program as a global variable,it causes ambiguity.
If you rename left to lef(or any other name that is not keyword or manipulator)in your program,your program works perfectly.

Check this link to know about left manipulator:
http://www.cplusplus.com/reference/ios/left

Hope it helps!!

Reference to 'internal' is ambiguous when converting to matrix?

The function you are trying to call is in the internal namespace which is nested inside the Rcpp namespace as you can see in the docs. Presumably you are using at least two namespaces with a nested namespace called internal. Therefore simply specifying

NumericMatrix testDFtoNM(DataFrame x) {
  NumericMatrix y = Rcpp::internal::convert_using_rfunction(x, "as.matrix");  
  return y;
}

should resolve the ambiguity.

Reference to ' ' is ambigous error in Xcode

Actually This error was cleared when I shift from iOS SDK 6.1 to 7.1(or any version higher that 6.1)

Reference to '' is ambiguous when including pure C header to Obj-C iOS project

You are including *.c files from prefix.h which is wrong. Always include only header files (*.h).

When you are including the implementation (*.c) files, the contents of the file is inserted as is, therefore you get the same definition in multiple places, leading to name collisions.

Why ambiguous reference error while using Left without parameters type?

It's because there's no common inferred types and you didn't specify the types for all the Either.

scala> for (v1 <- Right(2)) yield v1
res13: scala.util.Either[Nothing,Int] = Right(2)

Solution is to give them common types

for {
  v1 <- Left[Int,Int](1)
  v2 <- Right[Int,Int](2)
  v3 <- Right[Int,Int](3)
  v4 <- Left[Int,Int](4)
} yield v1 + v2 + v3 + v4

Which gives Left(1). This result makes sense due to Either being right-biased and for comprehension serving as a flatMap.

According to the documentation:
"Either is right-biased, which means that Right is assumed to be the default case to operate on. If it is Left, operations like map, flatMap, ... return the Left value unchanged"

https://www.scala-lang.org/api/2.12.0/scala/util/Either.html

Reference to 'X' Is Ambiguous