[commit: ghc] type-nats-simple: Just a comment to make it clear that AxiomRuleCo should be fully saturated. (c8606a7)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : type-nats-simple
Link       : http://ghc.haskell.org/trac/ghc/changeset/c8606a72b1608f551776dffb242a992db4b48a39/ghc

>---------------------------------------------------------------

commit c8606a72b1608f551776dffb242a992db4b48a39
Author: Iavor S. Diatchki <iavor.diatchki at gmail.com>
Date:   Sat Sep 7 13:42:46 2013 -0700

    Just a comment to make it clear that AxiomRuleCo should be fully saturated.


>---------------------------------------------------------------

c8606a72b1608f551776dffb242a992db4b48a39
 compiler/typecheck/TcEvidence.lhs |    2 ++
 compiler/types/Coercion.lhs       |    2 ++
 2 files changed, 4 insertions(+)

diff --git a/compiler/typecheck/TcEvidence.lhs b/compiler/typecheck/TcEvidence.lhs
index 2f3c12e..ffdce64 100644
--- a/compiler/typecheck/TcEvidence.lhs
+++ b/compiler/typecheck/TcEvidence.lhs
@@ -106,6 +106,8 @@ data TcCoercion
   | TcCoVarCo EqVar               -- variable always at role N
   | TcAxiomInstCo (CoAxiom Branched) Int [TcType] -- Int specifies branch number
                                                   -- See [CoAxiom Index] in Coercion.lhs
+  -- This is number of types and coercions are expected to macth to CoAxiomRule
+  -- (i.e., the CoAxiomRules are always fully saturated)
   | TcAxiomRuleCo CoAxiomRule [TcType] [TcCoercion]
   | TcSymCo TcCoercion
   | TcTransCo TcCoercion TcCoercion
diff --git a/compiler/types/Coercion.lhs b/compiler/types/Coercion.lhs
index 8498b7b..77d280e 100644
--- a/compiler/types/Coercion.lhs
+++ b/compiler/types/Coercion.lhs
@@ -181,6 +181,8 @@ data Coercion
   | SymCo Coercion             -- :: e -> e
   | TransCo Coercion Coercion  -- :: e -> e -> e
 
+    -- The number of types and coercions should match exactly the expectations
+    -- of the CoAxiomRule (i.e., the rule is fully saturated).
   | AxiomRuleCo CoAxiomRule [Type] [Coercion]
 
   -- These are destructors