X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=docs%2Fusers_guide%2Fusing.xml;h=b274f62d515ae4282f0c3ad052f9fe343e0ed7e9;hb=57aa4c8a73431b78a37428eb32af5978bfdc5f2b;hp=8cbcd35fca6cb6f6dcf01dbb8865bcaa9dc42ea1;hpb=0065d5ab628975892cea1ec7303f968c3338cbe1;p=ghc-hetmet.git

diff --git a/docs/users_guide/using.xml b/docs/users_guide/using.xml
index 8cbcd35..b274f62 100644
--- a/docs/users_guide/using.xml
+++ b/docs/users_guide/using.xml
@@ -1383,6 +1383,16 @@ f "2"    = 2
 	    <para>Turns off the full laziness optimisation (also known as
 	      let-floating).  Full laziness increases sharing, which can lead
 	      to increased memory residency.</para>
+
+            <para>NOTE: GHC doesn't implement complete full-laziness.
+            When optimisation in on, and
+            <option>-fno-full-laziness</option> is not given, some
+            transformations that increase sharing are performed, such
+            as extracting repeated computations from a loop.  These
+            are the same transformations that a fully lazy
+            implementation would do, the difference is that GHC
+            doesn't consistently apply full-laziness, so don't rely on
+            it.</para>
 	  </listitem>
 	</varlistentry>