Meaning-preserving SCC annotations (#15730)

This patch implements GHC Proposal #176:
  https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0176-scc-parsing.rst

Before the change:

  1 /                    2 / 2 = 0.25
  1 / {-# SCC "name" #-} 2 / 2 = 1.0

After the change:

  1 /                    2 / 2 = 0.25
  1 / {-# SCC "name" #-} 2 / 2 = parse error

11 files changed, 30 insertions, 5 deletions

diff --git a/testsuite/tests/parser/should_compile/T15730a.hs b/testsuite/tests/parser/should_compile/T15730a.hs
new file mode 100644
index 0000000000..5f1c45828a
--- /dev/null
+++ b/testsuite/tests/parser/should_compile/T15730a.hs
@@ -0,0 +1,5 @@
+x = 1 / 2 / 2
+a = {-# SCC ann #-} 1 / 2 / 2
+b = 1 / 2 / {-# SCC ann #-} 2
+
+main = print (x, a == x, b == x)
diff --git a/testsuite/tests/parser/should_compile/T15730a.stdout b/testsuite/tests/parser/should_compile/T15730a.stdout
new file mode 100644
index 0000000000..f8528ac72a
--- /dev/null
+++ b/testsuite/tests/parser/should_compile/T15730a.stdout
@@ -0,0 +1 @@
+(0.25,True,True)
diff --git a/testsuite/tests/parser/should_compile/all.T b/testsuite/tests/parser/should_compile/all.T
index 91aae139ab..85a7c3c172 100644
--- a/testsuite/tests/parser/should_compile/all.T
+++ b/testsuite/tests/parser/should_compile/all.T
@@ -162,3 +162,5 @@ test('proposal-229f',
        omit_ways(['profasm', 'profthreaded'])
      ],
      multimod_compile_and_run, ['proposal-229f.hs', ''])
+
+test('T15730a', normal, compile_and_run, [''])
diff --git a/testsuite/tests/parser/should_fail/T15730.hs b/testsuite/tests/parser/should_fail/T15730.hs
new file mode 100644
index 0000000000..98c7689e1c
--- /dev/null
+++ b/testsuite/tests/parser/should_fail/T15730.hs
@@ -0,0 +1,3 @@
+module T15730 where
+
+x = 1 / {-# SCC ann #-} 2 / 2
diff --git a/testsuite/tests/parser/should_fail/T15730.stderr b/testsuite/tests/parser/should_fail/T15730.stderr
new file mode 100644
index 0000000000..32b5b33759
--- /dev/null
+++ b/testsuite/tests/parser/should_fail/T15730.stderr
@@ -0,0 +1,2 @@
+
+T15730.hs:3:27: error: parse error on input ‘/’
diff --git a/testsuite/tests/parser/should_fail/T15730b.hs b/testsuite/tests/parser/should_fail/T15730b.hs
new file mode 100644
index 0000000000..01fa6e2eac
--- /dev/null
+++ b/testsuite/tests/parser/should_fail/T15730b.hs
@@ -0,0 +1,8 @@
+module T15730b where
+
+(.!) :: (a, a) -> Bool -> a
+a .! True = fst a
+a .! False = snd a
+
+t :: Bool -> Integer
+t x = (5,6) .! {-# SCC a1 #-} {-# SCC a2 #-} x :: Integer
diff --git a/testsuite/tests/parser/should_fail/T15730b.stderr b/testsuite/tests/parser/should_fail/T15730b.stderr
new file mode 100644
index 0000000000..5794dc00fe
--- /dev/null
+++ b/testsuite/tests/parser/should_fail/T15730b.stderr
@@ -0,0 +1,2 @@
+
+T15730b.hs:8:48: error: parse error on input ‘::’
diff --git a/testsuite/tests/parser/should_fail/all.T b/testsuite/tests/parser/should_fail/all.T
index c4a7a4f67b..e0000f009e 100644
--- a/testsuite/tests/parser/should_fail/all.T
+++ b/testsuite/tests/parser/should_fail/all.T
@@ -163,3 +163,5 @@ test('patFail008', normal, compile_fail, [''])
 test('patFail009', normal, compile_fail, [''])
 test('T17162', normal, compile_fail, [''])
 test('proposal-229c', normal, compile_fail, [''])
+test('T15730', normal, compile_fail, [''])
+test('T15730b', normal, compile_fail, [''])
diff --git a/testsuite/tests/perf/compiler/T15164.hs b/testsuite/tests/perf/compiler/T15164.hs
index 0f29623228..1b67c901d5 100644
--- a/testsuite/tests/perf/compiler/T15164.hs
+++ b/testsuite/tests/perf/compiler/T15164.hs
@@ -252,7 +252,7 @@ instance Rule f Primary => Rule f Factor where
 --          ::= name
 newtype FormalDesignator = MkFormalDesignator (NT Name)
 instance Rule f Name => Rule f FormalDesignator where
-  get = trace "FormalDesignator" $ {-# SCC "get_FormalDesignator" #-} MkFormalDesignator <$> n93
+  get = trace "FormalDesignator" $ {-# SCC "get_FormalDesignator" #-} (MkFormalDesignator <$> n93)
 
 -- formal_part
 --          ::= formal_designator
diff --git a/testsuite/tests/profiling/should_run/prof-doc-last.hs b/testsuite/tests/profiling/should_run/prof-doc-last.hs
index f5073fddc2..d74997d04b 100644
--- a/testsuite/tests/profiling/should_run/prof-doc-last.hs
+++ b/testsuite/tests/profiling/should_run/prof-doc-last.hs
@@ -2,6 +2,6 @@ main :: IO ()
 main = do let xs = [1..1000000]
           let ys = [1..2000000]
           print $ {-# SCC "last_xs" #-} last xs
-          print $ {-# SCC "last_init_xs" #-} last $ init xs
+          print $ {-# SCC "last_init_xs" #-} last (init xs)
           print $ {-# SCC "last_ys" #-} last ys
-          print $ {-# SCC "last_init_ys" #-}last $ init ys
+          print $ {-# SCC "last_init_ys" #-} last (init ys)
diff --git a/testsuite/tests/profiling/should_run/prof-doc-last.prof.sample b/testsuite/tests/profiling/should_run/prof-doc-last.prof.sample
index 371fad43d7..f67863df48 100644
--- a/testsuite/tests/profiling/should_run/prof-doc-last.prof.sample
+++ b/testsuite/tests/profiling/should_run/prof-doc-last.prof.sample
@@ -8,7 +8,7 @@
 COST CENTRE  MODULE SRC                       %time %alloc
 
 main.ys      Main   prof-doc-last.hs:3:15-31   39.7   37.5
-last_init_ys Main   prof-doc-last.hs:7:45-58   23.1   29.2
+last_init_ys Main   prof-doc-last.hs:7:46-59   23.1   29.2
 main.xs      Main   prof-doc-last.hs:2:15-31   23.1   18.7
 last_init_xs Main   prof-doc-last.hs:5:46-59   11.6   14.6
 last_xs      Main   prof-doc-last.hs:4:41-47    1.7    0.0
@@ -27,7 +27,7 @@ MAIN           MAIN                  <built-in>                     46
  CAF           GHC.IO.Encoding.Iconv <entire-module>                65          0    0.0    0.0     0.0    0.0
  main          Main                  prof-doc-last.hs:(2,1)-(7,58)  93          0    0.0    0.0   100.0  100.0
   last_init_xs Main                  prof-doc-last.hs:5:46-59       96          1   11.6   14.6    11.6   14.6
-  last_init_ys Main                  prof-doc-last.hs:7:45-58       99          1   23.1   29.2    23.1   29.2
+  last_init_ys Main                  prof-doc-last.hs:7:46-59       99          1   23.1   29.2    23.1   29.2
   last_xs      Main                  prof-doc-last.hs:4:41-47       94          1    1.7    0.0     1.7    0.0
   last_ys      Main                  prof-doc-last.hs:6:41-47       97          1    0.8    0.0     0.8    0.0
   main.xs      Main                  prof-doc-last.hs:2:15-31       95          1   23.1   18.7    23.1   18.7