Eliminate unnecessary parens

janestreet · Jun 14, 2024 · ec56a39 · ec56a39
1 parent d68154d
commit ec56a39
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Showing 4 changed files with 19 additions and 12 deletions.
diff --git a/lib/Ast.ml b/lib/Ast.ml
@@ -1946,6 +1946,13 @@ end = struct
     | { ast= {ptyp_desc= Ptyp_poly _; _}
       ; ctx= Typ {ptyp_desc= Ptyp_arrow _; _} } ->
         true
+    | { ast= {ptyp_desc= Ptyp_var (_, _) | Ptyp_any; _}
+      ; ctx= Typ {ptyp_desc= Ptyp_constr (_, args); _} }
+      when List.length args > 1 ->
+        (* Type variables and _ do not need parens when they appear as an
+           argument to a multi-parameter type constructor, even if they have
+           layout annotations. *)
+        false
     | {ast= {ptyp_desc= Ptyp_var (_, l); _}; ctx= _} when Option.is_some l ->
         true
     | { ast= {ptyp_desc= Ptyp_tuple ((Some _, _) :: _); _}

diff --git a/test/passing/tests/layout_annotation-erased.ml.js-ref b/test/passing/tests/layout_annotation-erased.ml.js-ref
@@ -68,11 +68,11 @@ let f : (_ : immediate) -> (_ : value) = fun _ -> assert false
 let g : (_ : value) -> (_ : immediate) = fun _ -> assert false
 
 type ('a : any, 'b : any, 'c : any) t4
-type 'a t5 = (('a : float64), int, bool) t4
+type 'a t5 = ('a : float64, int, bool) t4
 
-let f : ('a, (_ : value), bool) t4 -> int = fun _ -> 42
+let f : ('a, _ : value, bool) t4 -> int = fun _ -> 42
 
-type ('a, 'b, 'c) t6 = ('a, 'b, ('c : bits32)) t4
+type ('a, 'b, 'c) t6 = ('a, 'b, 'c : bits32) t4
 
 (********************************************)
 (* Test 3: Annotation on types in functions *)
@@ -208,7 +208,7 @@ let f_val : ('a : value). 'a -> 'a = fun x -> f_imm x
 
 type (_ : value) g = MkG : ('a : immediate). 'a g
 type t = int as (_ : immediate)
-type t = (('a : value), ('b : value)) t2
+type t = ('a : value, 'b : value) t2
 type ('a, 'b) t = ('a : value) * ('b : value)
 
 class c : object

diff --git a/test/passing/tests/layout_annotation.ml.js-ref b/test/passing/tests/layout_annotation.ml.js-ref
@@ -68,11 +68,11 @@ let f : (_ : immediate) -> (_ : value) = fun _ -> assert false
 let g : (_ : value) -> (_ : immediate) = fun _ -> assert false
 
 type ('a : any, 'b : any, 'c : any) t4
-type 'a t5 = (('a : float64), int, bool) t4
+type 'a t5 = ('a : float64, int, bool) t4
 
-let f : ('a, (_ : value), bool) t4 -> int = fun _ -> 42
+let f : ('a, _ : value, bool) t4 -> int = fun _ -> 42
 
-type ('a, 'b, 'c) t6 = ('a, 'b, ('c : bits32)) t4
+type ('a, 'b, 'c) t6 = ('a, 'b, 'c : bits32) t4
 
 (********************************************)
 (* Test 3: Annotation on types in functions *)
@@ -208,7 +208,7 @@ let f_val : ('a : value). 'a -> 'a = fun x -> f_imm x
 
 type (_ : value) g = MkG : ('a : immediate). 'a g
 type t = int as (_ : immediate)
-type t = (('a : value), ('b : value)) t2
+type t = ('a : value, 'b : value) t2
 type ('a, 'b) t = ('a : value) * ('b : value)
 
 class c : object

diff --git a/test/passing/tests/layout_annotation.ml.ref b/test/passing/tests/layout_annotation.ml.ref
@@ -98,11 +98,11 @@ let g : (_ : value) -> (_ : immediate) = fun _ -> assert false
 
 type ('a : any, 'b : any, 'c : any) t4
 
-type 'a t5 = (('a : float64), int, bool) t4
+type 'a t5 = ('a : float64, int, bool) t4
 
-let f : ('a, (_ : value), bool) t4 -> int = fun _ -> 42
+let f : ('a, _ : value, bool) t4 -> int = fun _ -> 42
 
-type ('a, 'b, 'c) t6 = ('a, 'b, ('c : bits32)) t4
+type ('a, 'b, 'c) t6 = ('a, 'b, 'c : bits32) t4
 
 (********************************************)
 (* Test 3: Annotation on types in functions *)
@@ -260,7 +260,7 @@ type (_ : value) g = MkG : ('a : immediate). 'a g
 
 type t = int as (_ : immediate)
 
-type t = (('a : value), ('b : value)) t2
+type t = ('a : value, 'b : value) t2
 
 type ('a, 'b) t = ('a : value) * ('b : value)