1 files changed, 52 insertions, 0 deletions
diff --git a/Help/policy/CMP0054.rst b/Help/policy/CMP0054.rst
new file mode 100644
index 000000000..1e000a662
--- /dev/null
+++ b/Help/policy/CMP0054.rst
@@ -0,0 +1,52 @@
+CMP0054
+-------
+
+Only interpret :command:`if` arguments as variables or keywords when unquoted.
+
+CMake 3.1 and above no longer implicitly dereference variables or
+interpret keywords in an :command:`if` command argument when
+it is a :ref:`Quoted Argument` or a :ref:`Bracket Argument`.
+
+The ``OLD`` behavior for this policy is to dereference variables and
+interpret keywords even if they are quoted or bracketed.
+The ``NEW`` behavior is to not dereference variables or interpret keywords
+that have been quoted or bracketed.
+
+Given the following partial example:
+
+::
+
+  set(A E)
+  set(E "")
+
+  if("${A}" STREQUAL "")
+    message("Result is TRUE before CMake 3.1 or when CMP0054 is OLD")
+  else()
+    message("Result is FALSE in CMake 3.1 and above if CMP0054 is NEW")
+  endif()
+
+After explicit expansion of variables this gives:
+
+::
+
+  if("E" STREQUAL "")
+
+With the policy set to ``OLD`` implicit expansion reduces this semantically to:
+
+::
+
+  if("" STREQUAL "")
+
+With the policy set to ``NEW`` the quoted arguments will not be
+further dereferenced:
+
+::
+
+  if("E" STREQUAL "")
+
+This policy was introduced in CMake version 3.1.
+CMake version |release| warns when the policy is not set and uses
+``OLD`` behavior.  Use the :command:`cmake_policy` command to set
+it to ``OLD`` or ``NEW`` explicitly.
+
+.. include:: DEPRECATED.txt