foreach loop variable still defined but emtpy after scope

Variables declared as loop variables in other languages are typically only available within the loop scope. However CMake has a strange mixed behavior. The variable is empty but defined after the loop.

macro(print)
  message("var: ${var}")
  if(DEFINED var)
    message("is set")
  else()
    message("is not set")
  endif()
  if("${var}" STREQUAL "")
    message("is empty")
  else()
    message("is not empty")
  endif()
endmacro()

foreach(var IN ITEMS a b c)
  print()
endforeach()
print()

Output:

var: a
is set
is not empty
var: b
is set
is not empty
var: c
is set
is not empty
var: 
is set
is empty

Expected:

• that last 'is set' should not be