+ namespace IMPORT_DEST. These form a linked list; NEXT is the next
+ element of the list. If the imported namespace or declaration has
+ been aliased within the IMPORT_DEST namespace, ALIAS is set to a
+ string representing the alias. Otherwise, ALIAS is NULL.
+ DECLARATION is the name of the imported declaration, if this import
+ statement represents one. Otherwise DECLARATION is NULL and this
+ import statement represents a namespace.
+
+ C++: using namespace A;
+ Fortran: use A
+ import_src = "A"
+ import_dest = local scope of the import statement even such as ""
+ alias = NULL
+ declaration = NULL
+ excludes = NULL
+
+ C++: using A::x;
+ Fortran: use A, only: x
+ import_src = "A"
+ import_dest = local scope of the import statement even such as ""
+ alias = NULL
+ declaration = "x"
+ excludes = NULL
+ The declaration will get imported as import_dest::x.
+
+ C++ has no way to import all names except those listed ones.
+ Fortran: use A, localname => x
+ import_src = "A"
+ import_dest = local scope of the import statement even such as ""
+ alias = "localname"
+ declaration = "x"
+ excludes = NULL
+ +
+ import_src = "A"
+ import_dest = local scope of the import statement even such as ""
+ alias = NULL
+ declaration = NULL
+ excludes = ["x"]
+ All the entries of A get imported except of "x". "x" gets imported as
+ "localname". "x" is not defined as a local name by this statement.
+
+ C++: namespace LOCALNS = A;
+ Fortran has no way to address non-local namespace/module.
+ import_src = "A"
+ import_dest = local scope of the import statement even such as ""
+ alias = "LOCALNS"
+ declaration = NULL
+ excludes = NULL
+ The namespace will get imported as the import_dest::LOCALNS
+ namespace.
+
+ C++ cannot express it, it would be something like: using localname
+ = A::x;
+ Fortran: use A, only localname => x
+ import_src = "A"
+ import_dest = local scope of the import statement even such as ""
+ alias = "localname"
+ declaration = "x"
+ excludes = NULL
+ The declaration will get imported as localname or
+ `import_dest`localname. */