Whitespace-sensitive bang patterns (#1087, #17162)wip/whitespace-and-lookahead

This patch implements a part of GHC Proposal #229 that covers five
operators:

* the bang operator (!)
* the tilde operator (~)
* the at operator (@)
* the dollar operator ($)
* the double dollar operator ($$)

Based on surrounding whitespace, these operators are disambiguated into
bang patterns, lazy patterns, strictness annotations, type
applications, splices, and typed splices.

This patch doesn't cover the (-) operator or the -Woperator-whitespace
warning, which are left as future work.

2 files changed, 16 insertions, 16 deletions

diff --git a/testsuite/tests/partial-sigs/should_compile/SplicesUsed.stderr b/testsuite/tests/partial-sigs/should_compile/SplicesUsed.stderr
index 88fc8d50b9..ad78bc9729 100644
--- a/testsuite/tests/partial-sigs/should_compile/SplicesUsed.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/SplicesUsed.stderr
@@ -1,23 +1,23 @@
 [1 of 2] Compiling Splices          ( Splices.hs, Splices.o )
 [2 of 2] Compiling SplicesUsed      ( SplicesUsed.hs, SplicesUsed.o )
 
-SplicesUsed.hs:7:16: warning: [-Wpartial-type-signatures (in -Wdefault)]
+SplicesUsed.hs:7:15: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • Found type wildcard ‘_’ standing for ‘Maybe Bool’
     • In the type ‘_’
       In the type signature: maybeBool :: (_)
 
-SplicesUsed.hs:8:15: warning: [-Wpartial-type-signatures (in -Wdefault)]
+SplicesUsed.hs:8:14: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • Found type wildcard ‘_a’ standing for ‘_’
       Where: ‘_’ is a rigid type variable bound by
                the inferred type of <expression> :: _ -> _
-               at SplicesUsed.hs:8:15-22
+               at SplicesUsed.hs:8:14-23
     • In an expression type signature: _a -> _a
       In the expression: id :: _a -> _a
       In the expression: (id :: _a -> _a) (Just True :: Maybe _)
     • Relevant bindings include
         maybeBool :: Maybe Bool (bound at SplicesUsed.hs:8:1)
 
-SplicesUsed.hs:8:27: warning: [-Wpartial-type-signatures (in -Wdefault)]
+SplicesUsed.hs:8:26: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • Found type wildcard ‘_’ standing for ‘Bool’
     • In the first argument of ‘Maybe’, namely ‘_’
       In the type ‘Maybe _’
@@ -25,7 +25,7 @@ SplicesUsed.hs:8:27: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • Relevant bindings include
         maybeBool :: Maybe Bool (bound at SplicesUsed.hs:8:1)
 
-SplicesUsed.hs:10:17: warning: [-Wpartial-type-signatures (in -Wdefault)]
+SplicesUsed.hs:10:16: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • Found type wildcard ‘_’ standing for ‘(Char, a)’
       Where: ‘a’ is a rigid type variable bound by
                the inferred type of charA :: a -> (Char, a)
@@ -33,7 +33,7 @@ SplicesUsed.hs:10:17: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • In the type ‘a -> (_)’
       In the type signature: charA :: a -> (_)
 
-SplicesUsed.hs:13:14: warning: [-Wpartial-type-signatures (in -Wdefault)]
+SplicesUsed.hs:13:13: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • Found type wildcard ‘_’ standing for ‘a -> Bool’
       Where: ‘a’ is a rigid type variable bound by
                the inferred type of filter' :: (a -> Bool) -> [a] -> [a]
@@ -41,7 +41,7 @@ SplicesUsed.hs:13:14: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • In the type ‘_ -> _ -> _’
       In the type signature: filter' :: (_ -> _ -> _)
 
-SplicesUsed.hs:13:14: warning: [-Wpartial-type-signatures (in -Wdefault)]
+SplicesUsed.hs:13:13: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • Found type wildcard ‘_’ standing for ‘[a]’
       Where: ‘a’ is a rigid type variable bound by
                the inferred type of filter' :: (a -> Bool) -> [a] -> [a]
@@ -49,7 +49,7 @@ SplicesUsed.hs:13:14: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • In the type ‘_ -> _ -> _’
       In the type signature: filter' :: (_ -> _ -> _)
 
-SplicesUsed.hs:13:14: warning: [-Wpartial-type-signatures (in -Wdefault)]
+SplicesUsed.hs:13:13: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • Found type wildcard ‘_’ standing for ‘[a]’
       Where: ‘a’ is a rigid type variable bound by
                the inferred type of filter' :: (a -> Bool) -> [a] -> [a]
@@ -57,27 +57,27 @@ SplicesUsed.hs:13:14: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • In the type ‘_ -> _ -> _’
       In the type signature: filter' :: (_ -> _ -> _)
 
-SplicesUsed.hs:16:3: warning: [-Wpartial-type-signatures (in -Wdefault)]
+SplicesUsed.hs:16:2: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • Found type wildcard ‘_’ standing for ‘Eq a’
       Where: ‘a’ is a rigid type variable bound by
                the inferred type of foo :: Eq a => a -> a -> Bool
-               at SplicesUsed.hs:16:3-10
+               at SplicesUsed.hs:16:2-11
     • In the type signature: foo :: _ => _
 
-SplicesUsed.hs:16:3: warning: [-Wpartial-type-signatures (in -Wdefault)]
+SplicesUsed.hs:16:2: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • Found type wildcard ‘_’ standing for ‘a -> a -> Bool’
       Where: ‘a’ is a rigid type variable bound by
                the inferred type of foo :: Eq a => a -> a -> Bool
-               at SplicesUsed.hs:16:3-10
+               at SplicesUsed.hs:16:2-11
     • In the type signature: foo :: _ => _
 
-SplicesUsed.hs:18:3: warning: [-Wpartial-type-signatures (in -Wdefault)]
+SplicesUsed.hs:18:2: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • Found type wildcard ‘_a’ standing for ‘Bool’
     • In the type signature: bar :: _a -> _b -> (_a, _b)
 
-SplicesUsed.hs:18:3: warning: [-Wpartial-type-signatures (in -Wdefault)]
+SplicesUsed.hs:18:2: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • Found type wildcard ‘_b’ standing for ‘_’
       Where: ‘_’ is a rigid type variable bound by
                the inferred type of bar :: Bool -> _ -> (Bool, _)
-               at SplicesUsed.hs:18:3-10
+               at SplicesUsed.hs:18:2-11
     • In the type signature: bar :: _a -> _b -> (_a, _b)
diff --git a/testsuite/tests/partial-sigs/should_fail/ExtraConstraintsWildcardInPatternSplice.stderr b/testsuite/tests/partial-sigs/should_fail/ExtraConstraintsWildcardInPatternSplice.stderr
index 2426e4cd27..2a83a36cc2 100644
--- a/testsuite/tests/partial-sigs/should_fail/ExtraConstraintsWildcardInPatternSplice.stderr
+++ b/testsuite/tests/partial-sigs/should_fail/ExtraConstraintsWildcardInPatternSplice.stderr
@@ -1,5 +1,5 @@
 
-ExtraConstraintsWildcardInPatternSplice.hs:5:8: error:
+ExtraConstraintsWildcardInPatternSplice.hs:5:6: error:
     • Found type wildcard ‘_’ standing for ‘_’
       Where: ‘_’ is a rigid type variable bound by
                the inferred type of foo :: _ -> ()