Ignore @uncurry attribute in uncurried mode.

Turns out that `@uncurry` attribute even in uncurried mode can produce js code that used`Curry`.
The `@uncurry` attribute will be deprecated.
For now, this PR ignores it.

Author: cristianoc

CHANGELOG.md

@@ -57,6 +57,8 @@
 - Make compiler libs ready for uncurried mode. https://github.com/rescript-lang/rescript-compiler/pull/6861
 - Make tests ready for uncurried mode. https://github.com/rescript-lang/rescript-compiler/pull/6862
 - Make gentype tests uncurried. https://github.com/rescript-lang/rescript-compiler/pull/6866
+- Ignore `@uncurry` attribute in uncurried mode, to avoid generating calls to `Curry` at runtime. https://github.com/rescript-lang/rescript-compiler/pull/6869
+
 #### :nail_care: Polish
 
 - Make the `--help` arg be prioritized in the CLI, so correctly prints help message and skip other commands. https://github.com/rescript-lang/rescript-compiler/pull/6667

jscomp/frontend/ast_attributes.ml

@@ -194,7 +194,10 @@ let iter_process_bs_string_int_unwrap_uncurry (attrs : t) =
       | "int" -> assign `Int attr
       | "ignore" -> assign `Ignore attr
       | "unwrap" -> assign `Unwrap attr
-      | "uncurry" -> assign (`Uncurry (Ast_payload.is_single_int payload)) attr
+      | "uncurry" ->
+        if !Config.uncurried = Uncurried then
+          Used_attributes.mark_used_attribute attr
+        else assign (`Uncurry (Ast_payload.is_single_int payload)) attr
       | _ -> ());
   !st
 

jscomp/test/build.ninja

@@ -0,0 +1,7 @@
+@@uncurried
+
+external map1: (array<'a>, @uncurry ('a => 'b)) => array<'b> = "map"
+let map1 = map1
+
+external map2: (array<'a>, ('a => 'b)) => array<'b> = "map"
+let map2 = map2

jscomp/test/ignore_uncurry_attribute.js

@@ -0,0 +1,5 @@
+external map1: (array<'a>, @uncurry ('a => 'b)) => array<'b> = "map"
+let map1 = map1
+
+external map2: (array<'a>, ('a => 'b)) => array<'b> = "map"
+let map2 = map2