Merge master into the ghc-new-co branch

[ghc-hetmet.git] / compiler / hsSyn / HsLit.lhs

diff --git a/compiler/hsSyn/HsLit.lhs b/compiler/hsSyn/HsLit.lhs
index 0874dda..4a565ff 100644 (file)
--- a/compiler/hsSyn/HsLit.lhs
+++ b/compiler/hsSyn/HsLit.lhs
@@ -63,8 +63,7 @@ instance Eq HsLit where
 data HsOverLit id      -- An overloaded literal
   = OverLit {
        ol_val :: OverLitVal, 
 data HsOverLit id      -- An overloaded literal
   = OverLit {
        ol_val :: OverLitVal, 

-       ol_rebindable :: Bool,          -- True <=> rebindable syntax
-                                       -- False <=> standard syntax
+       ol_rebindable :: Bool,          -- Note [ol_rebindable]

        ol_witness :: SyntaxExpr id,    -- Note [Overloaded literal witnesses]
        ol_type :: PostTcType }
   deriving (Data, Typeable)
        ol_witness :: SyntaxExpr id,    -- Note [Overloaded literal witnesses]
        ol_type :: PostTcType }
   deriving (Data, Typeable)

@@ -79,6 +78,19 @@ overLitType :: HsOverLit a -> Type
 overLitType = ol_type
 \end{code}
 
 overLitType = ol_type
 \end{code}
 

+Note [ol_rebindable]
+~~~~~~~~~~~~~~~~~~~~
+The ol_rebindable field is True if this literal is actually 
+using rebindable syntax.  Specifically:
+
+  False iff ol_witness is the standard one
+  True  iff ol_witness is non-standard
+
+Equivalently it's True if
+  a) RebindableSyntax is on
+  b) the witness for fromInteger/fromRational/fromString
+     that happens to be in scope isn't the standard one
+

 Note [Overloaded literal witnesses]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *Before* type checking, the SyntaxExpr in an HsOverLit is the
 Note [Overloaded literal witnesses]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *Before* type checking, the SyntaxExpr in an HsOverLit is the

@@ -89,7 +101,7 @@ This witness should replace the literal.
 
 This dual role is unusual, because we're replacing 'fromInteger' with 
 a call to fromInteger.  Reason: it allows commoning up of the fromInteger
 
 This dual role is unusual, because we're replacing 'fromInteger' with 
 a call to fromInteger.  Reason: it allows commoning up of the fromInteger

-calls, which wouldn't be possible if the desguarar made the application
+calls, which wouldn't be possible if the desguarar made the application.

 
 The PostTcType in each branch records the type the overload literal is
 found to have.
 
 The PostTcType in each branch records the type the overload literal is
 found to have.