[flow] Fix printer output of casting syntax when LHS of as or as const has low precedence

Summary: Changelog: [ide] Fix printer output of casting syntax when LHS of `as` or `as const` has low precedence

Reviewed By: panagosg7

Differential Revision: D54875911

fbshipit-source-id: 2ff2b71ecdad45a5db8b506436191199e75ddf36

Author: gkz

src/parser_utils/output/__tests__/js_layout_generator_test.ml

@@ -1980,7 +1980,13 @@ let tests =
            assert_statement_string ~ctxt "type T<in out A>=A;"
          );
          ("as_expression" >:: fun ctxt -> assert_expression_string ~ctxt "a as T");
+         ( "as_expression_precedence" >:: fun ctxt ->
+           assert_expression_string ~ctxt ~pretty:true "(x ?? a) as T"
+         );
          ("as_const_expression" >:: fun ctxt -> assert_expression_string ~ctxt "a as const");
+         ( "as_const_expression_precedence" >:: fun ctxt ->
+           assert_expression_string ~ctxt ~pretty:true "(x ?? a) as const"
+         );
          ("satisfies_expression" >:: fun ctxt -> assert_expression_string ~ctxt "a satisfies T");
          ( "type_parameter" >:: fun ctxt ->
            assert_statement_string ~ctxt "type a<a>=a;";

src/parser_utils/output/js_layout_generator.ml

@@ -1263,8 +1263,8 @@ and expression ?(ctxt = normal_context) ~opts (root_expr : (Loc.t, Loc.t) Ast.Ex
       | E.JSXElement el -> jsx_element ~opts loc el
       | E.JSXFragment fr -> jsx_fragment ~opts loc fr
       | E.TypeCast cast -> type_cast ~opts loc cast
-      | E.AsConstExpression cast -> as_const_expression ~opts loc cast
-      | E.AsExpression cast -> as_expression ~opts loc cast
+      | E.AsConstExpression cast -> as_const_expression ~ctxt ~opts ~precedence loc cast
+      | E.AsExpression cast -> as_expression ~ctxt ~opts ~precedence loc cast
       | E.TSSatisfies cast -> ts_satisfies ~opts loc cast
       | E.Import { E.Import.argument; comments } ->
         layout_node_with_comments_opt loc comments
@@ -1487,18 +1487,25 @@ and type_cast ~opts loc cast =
   layout_node_with_comments_opt loc comments
   @@ wrap_in_parens (fuse [expr_layout; type_annotation ~opts annot])
 
-and as_const_expression ~opts loc cast =
+and as_const_expression ~ctxt ~opts ~precedence loc cast =
   let open Ast.Expression.AsConstExpression in
   let { expression = expr; comments } = cast in
-  let expr_layout = expression ~opts expr in
+  let expr_layout = expression_with_parens ~ctxt ~opts ~precedence expr in
   let rhs = [Atom "as"; space; Atom "const"] in
   layout_node_with_comments_opt loc comments @@ fuse [expr_layout; space; fuse rhs]
 
-and as_expression ~opts loc cast =
+and as_expression ~ctxt ~opts ~precedence loc cast =
   let open Ast.Expression.AsExpression in
   let { expression = expr; annot = (_, annot); comments } = cast in
   layout_node_with_comments_opt loc comments
-  @@ fuse [expression ~opts expr; space; Atom "as"; space; type_ ~opts annot]
+  @@ fuse
+       [
+         expression_with_parens ~ctxt ~opts ~precedence expr;
+         space;
+         Atom "as";
+         space;
+         type_ ~opts annot;
+       ]
 
 and ts_satisfies ~opts loc cast =
   let open Ast.Expression.TSSatisfies in

tests/annotate_exports_import_cycle/annotate_exports_import_cycle.exp

@@ -27,7 +27,7 @@ import type { E, C } from "./lib";import { foo, baz } from "./lib";
 const a = require("./a");
 
 module.exports = [
-  0 < 1 ? foo() : baz() as C | E
+  (0 < 1 ? foo() : baz()) as C | E
 ];
 
 >>> Launching report...
@@ -86,7 +86,7 @@ import type { E, C } from "./lib";import { foo, baz } from "./lib";
 const a = require("./a");
 
 module.exports = [
-  0 < 1 ? foo() : baz() as C | E
+  (0 < 1 ? foo() : baz()) as C | E
 ];
 
 >>> ./error-a.js
@@ -100,8 +100,8 @@ import { error_foo, error_bar } from "./error-lib";
 const b = require("./error-b");
 
 module.exports = [
-  0 < 1 ? foo() : error_foo() as C | C,
-  0 < 1 ? bar() : error_bar() as D | D,
+  (0 < 1 ? foo() : error_foo()) as C | C,
+  (0 < 1 ? bar() : error_bar()) as D | D,
 ];
 
 >>> ./error-b.js
@@ -113,8 +113,8 @@ import { error_foo, error_baz } from "./error-lib";
 const a = require("./error-a");
 
 module.exports = [
-  0 < 1 ? foo() : error_foo() as C | C,
-  0 < 1 ? baz() : error_baz() as E | E,
+  (0 < 1 ? foo() : error_foo()) as C | C,
+  (0 < 1 ? baz() : error_baz()) as E | E,
 ];
 
 
@@ -124,14 +124,14 @@ module.exports = [
 <   0 < 1 ? foo() : error_foo(),
 <   0 < 1 ? bar() : error_bar(),
 ---
->   0 < 1 ? foo() : error_foo() as C | C,
->   0 < 1 ? bar() : error_bar() as D | D,
+>   (0 < 1 ? foo() : error_foo()) as C | C,
+>   (0 < 1 ? bar() : error_bar()) as D | D,
 
 >>> ./error-b.js
 9,10c9,10
 <   0 < 1 ? foo() : error_foo(),
 <   0 < 1 ? baz() : error_baz(),
 ---
->   0 < 1 ? foo() : error_foo() as C | C,
->   0 < 1 ? baz() : error_baz() as E | E,
+>   (0 < 1 ? foo() : error_foo()) as C | C,
+>   (0 < 1 ? baz() : error_baz()) as E | E,
 

tests/annotate_exports_no_import_on_error/annotate_exports_no_import_on_error.exp

@@ -53,7 +53,7 @@ module.exports = (foo() as C); // error: C is not exported
 import type { D } from "./lib-2";import { foo, bar } from "./lib-2";
 
 module.exports._1 = (foo() as C); // error: C is not exported
-module.exports._2 = (0 < 1 ? foo() : bar() as C | D); // error: C is not exported, even though D is okay
+module.exports._2 = ((0 < 1 ? foo() : bar()) as C | D); // error: C is not exported, even though D is okay
 module.exports._3 = (bar() as D); // okay
 
 
@@ -70,5 +70,5 @@ module.exports._3 = (bar() as D); // okay
 < module.exports._2 = 0 < 1 ? foo() : bar(); // error: C is not exported, even though D is okay
 ---
 > module.exports._1 = (foo() as C); // error: C is not exported
-> module.exports._2 = (0 < 1 ? foo() : bar() as C | D); // error: C is not exported, even though D is okay
+> module.exports._2 = ((0 < 1 ? foo() : bar()) as C | D); // error: C is not exported, even though D is okay