Implement printing of parens (precedence) for await expressions

Author: Maxim

src/res_parens.ml

@@ -45,6 +45,8 @@ let callExpr expr =
        | Pexp_try _ | Pexp_while _ | Pexp_for _ | Pexp_ifthenelse _ );
     } ->
       Parenthesized
+    | _ when ParsetreeViewer.hasAwaitAttribute expr.pexp_attributes ->
+      Parenthesized
     | _ -> Nothing)
 
 let structureExpr expr =
@@ -96,6 +98,8 @@ let unaryExprOperand expr =
        | Pexp_try _ | Pexp_while _ | Pexp_for _ | Pexp_ifthenelse _ );
     } ->
       Parenthesized
+    | _ when ParsetreeViewer.hasAwaitAttribute expr.pexp_attributes ->
+      Parenthesized
     | _ -> Nothing)
 
 let binaryExprOperand ~isLhs expr =
@@ -120,6 +124,8 @@ let binaryExprOperand ~isLhs expr =
     | expr when ParsetreeViewer.isBinaryExpression expr -> Parenthesized
     | expr when ParsetreeViewer.isTernaryExpr expr -> Parenthesized
     | {pexp_desc = Pexp_lazy _ | Pexp_assert _} when isLhs -> Parenthesized
+    | _ when ParsetreeViewer.hasAwaitAttribute expr.pexp_attributes ->
+      Parenthesized
     | {Parsetree.pexp_attributes = attrs} ->
       if ParsetreeViewer.hasPrintableAttributes attrs then Parenthesized
       else Nothing)
@@ -196,6 +202,8 @@ let lazyOrAssertExprRhs expr =
        | Pexp_try _ | Pexp_while _ | Pexp_for _ | Pexp_ifthenelse _ );
     } ->
       Parenthesized
+    | _ when ParsetreeViewer.hasAwaitAttribute expr.pexp_attributes ->
+      Parenthesized
     | _ -> Nothing)
 
 let isNegativeConstant constant =
@@ -240,6 +248,8 @@ let fieldExpr expr =
        | Pexp_ifthenelse _ );
     } ->
       Parenthesized
+    | _ when ParsetreeViewer.hasAwaitAttribute expr.pexp_attributes ->
+      Parenthesized
     | _ -> Nothing)
 
 let setFieldExprRhs expr =
@@ -302,6 +312,8 @@ let jsxPropExpr expr =
       }
         when startsWithMinus x ->
         Parenthesized
+      | _ when ParsetreeViewer.hasAwaitAttribute expr.pexp_attributes ->
+        Parenthesized
       | {
        Parsetree.pexp_desc =
          ( Pexp_ident _ | Pexp_constant _ | Pexp_field _ | Pexp_construct _
@@ -338,6 +350,8 @@ let jsxChildExpr expr =
       }
         when startsWithMinus x ->
         Parenthesized
+      | _ when ParsetreeViewer.hasAwaitAttribute expr.pexp_attributes ->
+        Parenthesized
       | {
        Parsetree.pexp_desc =
          ( Pexp_ident _ | Pexp_constant _ | Pexp_field _ | Pexp_construct _

tests/printer/expr/asyncAwait.res

@@ -16,4 +16,17 @@ let f = async (. a, b) => a + b
 let maybeSomeValue = switch await fetchData(url) {    
 | data => Some(data)
 | exception JsError(_) => None
-}
+}
+
+(await f)(a, b) 
+-(await f)
+await 1 + await 2
+
+lazy (await f())
+assert (await f())
+
+(await f).json()
+
+user.data = await fetch()
+
+<Navbar promise={await gc()}>{await weirdReactSuspenseApi}</Navbar>

tests/printer/expr/expected/asyncAwait.res.txt

@@ -16,3 +16,16 @@ let maybeSomeValue = switch await fetchData(url) {
 | data => Some(data)
 | exception JsError(_) => None
 }
+
+(await f)(a, b)
+-(await f)
+(await 1) + (await 2)
+
+lazy (await f())
+assert (await f())
+
+(await f).json()
+
+user.data = await fetch()
+
+<Navbar promise={await gc()}> {await weirdReactSuspenseApi} </Navbar>