Add HsEmbellished type to hsSynwip/embelleshed-rdr

Summary:
A RdrName can be parsed with parens or backquotes if it is used prefix or infix
respectively when it is normally not used that way.

This is not captured in hsSyn, and must be inferred from the occName when pretty
printing, or using the API annotations.

Introduce a wrapper type around the name to capture this

    data Embellished name
      = EName       name
      | EParens     (Located name)
      | EBackquotes (Located name)

So that we now have

    data HsExpr id
      = HsVar     (LEmbellished id)   -- ^ Variable

and in the other relevant points in hsSyn.

Test Plan: ./validate

Reviewers: bgamari, austin, goldfire

Subscribers: goldfire, thomie, mpickering, snowleopard

Differential Revision: https://phabricator.haskell.org/D3145

1 files changed, 8 insertions, 6 deletions

diff --git a/compiler/hsSyn/HsExpr.hs b/compiler/hsSyn/HsExpr.hs
index 71c408984b..0008827080 100644
--- a/compiler/hsSyn/HsExpr.hs
+++ b/compiler/hsSyn/HsExpr.hs
@@ -41,6 +41,7 @@ import Util
 import Outputable
 import FastString
 import Type
+import HsEmbellished
 
 -- libraries:
 import Data.Data hiding (Fixity(..))
@@ -125,7 +126,7 @@ noSyntaxExpr = SyntaxExpr { syn_expr      = HsLit (HsString NoSourceText
 -- | Make a 'SyntaxExpr Name' (the "rn" is because this is used in the
 -- renamer), missing its HsWrappers.
 mkRnSyntaxExpr :: Name -> SyntaxExpr Name
-mkRnSyntaxExpr name = SyntaxExpr { syn_expr      = HsVar $ noLoc name
+mkRnSyntaxExpr name = SyntaxExpr { syn_expr      = HsVar $ noLoc $ EName name
                                  , syn_arg_wraps = []
                                  , syn_res_wrap  = WpHole }
   -- don't care about filling in syn_arg_wraps because we're clearly
@@ -274,7 +275,7 @@ information to use is the GlobalRdrEnv itself.
 
 -- | A Haskell expression.
 data HsExpr id
-  = HsVar     (Located id)   -- ^ Variable
+  = HsVar     (LEmbellished id)   -- ^ Variable
 
                              -- See Note [Located RdrNames]
 
@@ -667,12 +668,13 @@ data HsExpr id
   -- These constructors only appear temporarily in the parser.
   -- The renamer translates them into the Right Thing.
 
+  -- AZ: TODO: Needs to be embellished too, for backquotes
   | EWildPat                 -- wildcard
 
   -- | - 'ApiAnnotation.AnnKeywordId' : 'ApiAnnotation.AnnAt'
 
   -- For details on above see note [Api annotations] in ApiAnnotation
-  | EAsPat      (Located id) -- as pattern
+  | EAsPat      (LEmbellished id) -- as pattern
                 (LHsExpr id)
 
   -- | - 'ApiAnnotation.AnnKeywordId' : 'ApiAnnotation.AnnRarrow'
@@ -2242,7 +2244,7 @@ data HsBracket id = ExpBr (LHsExpr id)   -- [|  expr  |]
                   | DecBrL [LHsDecl id]  -- [d| decls |]; result of parser
                   | DecBrG (HsGroup id)  -- [d| decls |]; result of renamer
                   | TypBr (LHsType id)   -- [t| type  |]
-                  | VarBr Bool id        -- True: 'x, False: ''T
+                  | VarBr Bool (LEmbellished id) -- True: 'x, False: ''T
                                          -- (The Bool flag is used only in pprHsBracket)
                   | TExpBr (LHsExpr id)  -- [||  expr  ||]
 deriving instance (DataId id) => Data (HsBracket id)
@@ -2261,9 +2263,9 @@ pprHsBracket (PatBr p)   = thBrackets (char 'p') (ppr p)
 pprHsBracket (DecBrG gp) = thBrackets (char 'd') (ppr gp)
 pprHsBracket (DecBrL ds) = thBrackets (char 'd') (vcat (map ppr ds))
 pprHsBracket (TypBr t)   = thBrackets (char 't') (ppr t)
-pprHsBracket (VarBr True n)
+pprHsBracket (VarBr True (L _ n))
   = char '\'' <> pprPrefixOcc n
-pprHsBracket (VarBr False n)
+pprHsBracket (VarBr False (L _ n))
   = text "''" <> pprPrefixOcc n
 pprHsBracket (TExpBr e)  = thTyBrackets (ppr e)