Compilation of my ghc tree with ghc-6.12.2 -dcore-lint fails.

In the middle of the work on GHC backend I triggered a bug in GHC 6.12.2. When using 6.12.2 to compile compiler/cmm/CmmSpillReload.hs we get:

*** Core Lint Errors: in result of Simplifier mode gentle, iteration 1 out of 4 ***
	<no location info>:
	    In the expression: ic_a1xa @ $co$_a1wz
	    Kinds don't match in type application:
	    Type variable: co_wild_B1 :: e_a1tx ~ Compiler.Hoopl.Graph.C
	    Arg type: $co$_a1wz :: e_a1zK ~ Compiler.Hoopl.Graph.C

After discussing with simonpj, I have snapshotted the source tree, as I could not reduce the test case.

When compiling with ghc-6.12.2 -dcore-lint, the compilation fails in the stage 1. It is enough to invoke 'make' in the tree to get to the compilation error. I attach the dump of -dcore-lint output.

The file causing the bug is compiler/cmm/CmmSpillReload.hs. On line 131, there is a description of a change that makes the source compile.