Fix parens removed in series of pipes for anonymous uncurried function (rescript-lang#6766)

Handle precedence of uncurried anonymous function in pipe chains.

Author: shulhi

CHANGELOG.md

@@ -38,6 +38,8 @@
 - Fix indent in generated js code. https://github.com/rescript-lang/rescript-compiler/pull/6747
 - In generated code, use `let` instead of `var`. https://github.com/rescript-lang/rescript-compiler/pull/6102
 - Turn off transformation for closures inside loops when capturing loop variables, now that `let` is emitted instead of `var`. https://github.com/rescript-lang/rescript-compiler/pull/6480
+- Fix formatter eats comments on the first argument of a uncurried function. https://github.com/rescript-lang/rescript-compiler/pull/6763 
+- Fix formatter removes parens in pipe operator with anonymous uncurried function. https://github.com/rescript-lang/rescript-compiler/pull/6766
 
 # 11.1.0
 

jscomp/syntax/src/res_parens.ml

@@ -180,6 +180,7 @@ let flattenOperandRhs parentOperator rhs =
     let precParent = ParsetreeViewer.operatorPrecedence parentOperator in
     let precChild = ParsetreeViewer.operatorPrecedence operator in
     precParent >= precChild || rhs.pexp_attributes <> []
+  | Pexp_construct ({txt = Lident "Function$"}, Some _) -> true
   | Pexp_constraint ({pexp_desc = Pexp_pack _}, {ptyp_desc = Ptyp_package _}) ->
     false
   | Pexp_fun _ when ParsetreeViewer.isUnderscoreApplySugar rhs -> false

jscomp/syntax/tests/printer/expr/expected/smartPipe.res.txt

@@ -31,3 +31,11 @@ let messages = React.useMemo(() =>
   ->Array.filter(ChatMessage.isVisibleInSimpleFilter)
   ->Array.toSorted(ChatMessage.compareByDateAsc)
 , [messagesById])
+
+f->(v => g(x))->g
+
+f->v->g
+
+x->(v => g(x))->f->(v => g(x)->k)->g
+
+f->(v => g(x)->k->(x => s(x)))->g

jscomp/syntax/tests/printer/expr/smartPipe.res

@@ -29,3 +29,10 @@ let messages = React.useMemo(() =>
   ->Array.toSorted(ChatMessage.compareByDateAsc)
 , [messagesById])
 
+f->(v => g(x))->g
+
+f->(v)->g
+
+x->(v => g(x))->f->(v => g(x)->k)->g
+
+f->(v => g(x)->k->(x => s(x)))->g