+Note [lazyId magic]
+~~~~~~~~~~~~~~~~~~~
+ lazy :: forall a?. a? -> a? (i.e. works for unboxed types too)
+
+Used to lazify pseq: pseq a b = a `seq` lazy b
+
+Also, no strictness: by being a built-in Id, all the info about lazyId comes from here,
+not from GHC.Base.hi. This is important, because the strictness
+analyser will spot it as strict!
+
+Also no unfolding in lazyId: it gets "inlined" by a HACK in CorePrep.
+It's very important to do this inlining *after* unfoldings are exposed
+in the interface file. Otherwise, the unfolding for (say) pseq in the
+interface file will not mention 'lazy', so if we inline 'pseq' we'll totally
+miss the very thing that 'lazy' was there for in the first place.
+See Trac #3259 for a real world example.
+
+lazyId is defined in GHC.Base, so we don't *have* to inline it. If it
+appears un-applied, we'll end up just calling it.
+
+-------------------------------------------------------------