3 files changed, 27 insertions, 5 deletions
diff --git a/compiler/GHC/Rename/Expr.hs b/compiler/GHC/Rename/Expr.hs
index 49af58bd1c..4ee8870318 100644
--- a/compiler/GHC/Rename/Expr.hs
+++ b/compiler/GHC/Rename/Expr.hs
@@ -248,8 +248,9 @@ finishHsVar (L l name)
 rnUnboundVar :: RdrName -> RnM (HsExpr GhcRn, FreeVars)
 rnUnboundVar v = do
   deferOutofScopeVariables <- goptM Opt_DeferOutOfScopeVariables
+  -- See Note [Reporting unbound names] for difference between qualified and unqualified names.
   unless (isUnqual v || deferOutofScopeVariables) (reportUnboundName v >> return ())
-  return (HsUnboundVar noExtField (rdrNameOcc v), emptyFVs)
+  return (HsUnboundVar noExtField v, emptyFVs)
 
 rnExpr (HsVar _ (L l v))
   = do { dflags <- getDynFlags
@@ -751,6 +752,28 @@ bindNonRec will automatically do the right thing, giving us:
     case expr of y -> (\x -> op y x)
 
 See #18151.
+
+Note [Reporting unbound names]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Faced with an out-of-scope `RdrName` there are two courses of action
+A. Report an error immediately (and return a HsUnboundVar). This will halt GHC after the renamer is complete
+B. Return a HsUnboundVar without reporting an error.  That will allow the typechecker to run, which in turn
+   can give a better error message, notably giving the type of the variable via the "typed holes" mechanism.
+
+When `-fdefer-out-of-scope-variables` is on we follow plan B.
+
+When it is not, we follow plan B for unqualified names, and plan A for qualified names.
+
+If a name is qualified, and out of scope, then by default an error will be raised
+because the user was already more precise. They specified a specific qualification
+and either
+  * The qualification didn't exist, so that precision was wrong.
+  * Or the qualification existed and the thing we were looking for wasn't where
+    the qualification said it would be.
+
+However we can still defer this error completely, and we do defer it if
+`-fdefer-out-of-scope-variables` is enabled.
+
 -}
 
 {-
diff --git a/compiler/GHC/Rename/HsType.hs b/compiler/GHC/Rename/HsType.hs
index bca65c7cad..aaaa249ba2 100644
--- a/compiler/GHC/Rename/HsType.hs
+++ b/compiler/GHC/Rename/HsType.hs
@@ -1425,7 +1425,7 @@ data NegationHandling = ReassociateNegation | KeepNegationIntact
 -- | Name of an operator in an operator application or section
 data OpName = NormalOp Name             -- ^ A normal identifier
             | NegateOp                  -- ^ Prefix negation
-            | UnboundOp OccName         -- ^ An unbound identifier
+            | UnboundOp RdrName         -- ^ An unbound identifier
             | RecFldOp (FieldOcc GhcRn) -- ^ A record field occurrence
 
 instance Outputable OpName where
@@ -1607,7 +1607,7 @@ checkSectionPrec direction section op arg
 lookupFixityOp :: OpName -> RnM Fixity
 lookupFixityOp (NormalOp n)  = lookupFixityRn n
 lookupFixityOp NegateOp      = lookupFixityRn negateName
-lookupFixityOp (UnboundOp u) = lookupFixityRn (mkUnboundName u)
+lookupFixityOp (UnboundOp u) = lookupFixityRn (mkUnboundName (occName u))
 lookupFixityOp (RecFldOp f)  = lookupFieldFixityRn f
 
 
diff --git a/compiler/GHC/Rename/Module.hs b/compiler/GHC/Rename/Module.hs
index 537e161e42..97726a279c 100644
--- a/compiler/GHC/Rename/Module.hs
+++ b/compiler/GHC/Rename/Module.hs
@@ -1370,8 +1370,7 @@ badRuleLhsErr name lhs bad_e
     err =
       case bad_e of
         HsUnboundVar _ uv ->
-          let rdr = mkRdrUnqual uv
-          in  pprScopeError rdr $ notInScopeErr WL_Global (mkRdrUnqual uv)
+          pprScopeError uv $ notInScopeErr WL_Global uv
         _ -> text "Illegal expression:" <+> ppr bad_e
 
 {- **************************************************************