Fix minimize-parens feature, Add a few basic tests

data/12-features/minimize-parentheses.blt

@@ -0,0 +1,27 @@
+#group feature/minimize-parens
+
+#golden minimize parens basic test
+-- brittany { lconfig_operatorParenthesisRefactorMode: PRMMinimize }
+func = func (abc) (def)
+#expected
+-- brittany { lconfig_operatorParenthesisRefactorMode: PRMMinimize }
+func = func abc def
+
+#test minimize parens test that it keep necessary parens
+-- brittany { lconfig_operatorParenthesisRefactorMode: PRMMinimize }
+func = func (abc False) ("asd" ++ "def")
+
+
+#golden minimize nested parens 1
+-- brittany { lconfig_operatorParenthesisRefactorMode: PRMMinimize }
+func = func ((((((((nested))))))))
+#expected
+-- brittany { lconfig_operatorParenthesisRefactorMode: PRMMinimize }
+func = func nested
+
+#golden minimize nested parens 2
+-- brittany { lconfig_operatorParenthesisRefactorMode: PRMMinimize }
+func = func ((((((((nested + expression))))))))
+#expected
+-- brittany { lconfig_operatorParenthesisRefactorMode: PRMMinimize }
+func = func (nested + expression)

data/15-regressions.blt

@@ -1060,13 +1060,6 @@ func = do
     )
     `shouldReturn` thing
 
-#golden minimize parens basic test
--- brittany { lconfig_operatorParenthesisRefactorMode: PRMMinimize }
-func = func (abc) (def)
-#expected
--- brittany { lconfig_operatorParenthesisRefactorMode: PRMMinimize }
-func = func abc def
-
 #test wandering comment at end of datadecl
 data ReformatParenMode
   = ReformatParenModeKeep  -- don't modify parens at all

source/library/Language/Haskell/Brittany/Internal/Components/OpTree.hs

@@ -184,9 +184,14 @@ addAllParens topLevelParen = \case
 
 remSuperfluousParens :: Int -> OpTree -> OpTree
 remSuperfluousParens outerFixity = \case
-  x@OpLeaf{}                 -> x
-  OpUnknown _ locO locC c [] -> OpUnknown NoParen locO locC c []
-  x@OpUnknown{}              -> x
+  x@OpLeaf{} -> x
+  OpUnknown _ locO locC c@(OpLeaf doc) [] | isLit doc ->
+    OpUnknown NoParen locO locC c []
+  OpUnknown _ locO locC c@(OpUnknown ParenWithSpace _ _ _ _) [] ->
+    OpUnknown NoParen locO locC (remSuperfluousParens 11 c) []
+  OpUnknown _ locO locC c@(OpUnknown ParenNoSpace _ _ _ _) [] ->
+    OpUnknown NoParen locO locC (remSuperfluousParens 11 c) []
+  x@OpUnknown{} -> x
   OpKnown paren locO locC fixity c cs ->
     OpKnown
       -- We do not support removing superfluous parens around
@@ -200,7 +205,22 @@ remSuperfluousParens outerFixity = \case
       fixity
       (remSuperfluousParens (fixLevel fixity) c)
       [ (op, remSuperfluousParens (fixLevel fixity) tree) | (op, tree) <- cs ]
-  where fixLevel (Fixity _ i _) = i
+ where
+  fixLevel (Fixity _ i _) = i
+  isLit = \case
+    (_, BDFlushCommentsPrior _ x ) -> isLit x
+    (_, BDFlushCommentsPost _ _ x) -> isLit x
+    (_, BDQueueComments _ x      ) -> isLit x
+    (_, BDEntryDelta _ x         ) -> isLit x
+    (_, BDForceAlt _ x           ) -> isLit x
+    (_, BDDebug _ x              ) -> isLit x
+    (_, BDAddBaseY _ x           ) -> isLit x
+    (_, BDBaseYPushCur x         ) -> isLit x
+    (_, BDIndentLevelPushCur x   ) -> isLit x
+    (_, BDIndentLevelPop x       ) -> isLit x
+    (_, BDLit{}                  ) -> True
+    _                              -> False
+
 
 hardcodedFixity :: Bool -> String -> Maybe Fixity
 hardcodedFixity allowUnqualify = \case