Add $Call utility type

Reviewed By: samwgoldman Differential Revision: D5722285 fbshipit-source-id: 72c9377102e74b53099573c43693d789b7cccef6
facebook · Sep 6, 2017 · ac7d9ac · ac7d9ac · jcready · Sep 19, 2017
1 parent bd938ab
commit ac7d9ac
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Showing 11 changed files with 309 additions and 7 deletions.
diff --git a/src/typing/debug_js.ml b/src/typing/debug_js.ml
@@ -1085,25 +1085,28 @@ and json_of_destructor_impl json_cx = Hh_json.(function
   | ValuesType -> JSON_Object [
       "values", JSON_Bool true;
     ]
+  | CallType args -> JSON_Object [
+      "args", JSON_Array (List.map (_json_of_t json_cx) args);
+    ]
   | TypeMap tmap -> json_of_type_map json_cx tmap
   | ReactElementPropsType -> JSON_Object [
-    "reactElementProps", JSON_Bool true
-  ]
+      "reactElementProps", JSON_Bool true
+    ]
   | ReactElementRefType -> JSON_Object [
-    "reactElementRef", JSON_Bool true
-  ]
+      "reactElementRef", JSON_Bool true
+    ]
 )
 
 and json_of_type_map json_cx = check_depth json_of_type_map_impl json_cx
 and json_of_type_map_impl json_cx = Hh_json.(function
   | TupleMap t -> JSON_Object [
-      "tupleMap", _json_of_t json_cx t
+      "tupleMap", _json_of_t json_cx t;
     ]
   | ObjectMap t -> JSON_Object [
-      "objectMap", _json_of_t json_cx t
+      "objectMap", _json_of_t json_cx t;
     ]
   | ObjectMapi t -> JSON_Object [
-      "objectMapi", _json_of_t json_cx t
+      "objectMapi", _json_of_t json_cx t;
     ]
 )
 
@@ -1532,6 +1535,7 @@ and dump_t_ (depth, tvars) cx t =
     | Bind _ -> "bind"
     | SpreadType _ -> "spread"
     | ValuesType -> "values"
+    | CallType _ -> "function call"
     | TypeMap (TupleMap _) -> "tuple map"
     | TypeMap (ObjectMap _) -> "object map"
     | TypeMap (ObjectMapi _) -> "object mapi"
@@ -2155,6 +2159,7 @@ let string_of_destructor = function
   | Bind _ -> "Bind"
   | SpreadType _ -> "Spread"
   | ValuesType -> "Values"
+  | CallType _ -> "CallType"
   | TypeMap (TupleMap _) -> "TupleMap"
   | TypeMap (ObjectMap _) -> "ObjectMap"
   | TypeMap (ObjectMapi _) -> "ObjectMapi"

diff --git a/src/typing/flow_js.ml b/src/typing/flow_js.ml
@@ -6717,6 +6717,10 @@ and eval_destructor cx ~trace reason curr_t s i =
             let state = { todo_rev; acc = [] } in
             ObjSpreadT (reason, options, tool, state, tvar)
         | ValuesType -> GetValuesT (reason, tvar)
+        | CallType args ->
+          let call = mk_functioncalltype (List.map (fun arg -> Arg arg) args) tvar in
+          let call = {call with call_strict_arity = false} in
+          CallT (reason, call)
         | TypeMap tmap -> MapTypeT (reason, tmap, tvar)
         | ReactElementPropsType -> ReactKitT (reason, React.GetProps tvar)
         | ReactElementRefType -> ReactKitT (reason, React.GetRef tvar)

diff --git a/src/typing/gc_js.ml b/src/typing/gc_js.ml
@@ -380,6 +380,7 @@ and gc_destructor cx state = function
   | ElementType t -> gc cx state t
   | Bind t -> gc cx state t
   | SpreadType (_, ts) -> List.iter (gc cx state) ts
+  | CallType args -> List.iter (gc cx state) args
   | TypeMap tmap -> gc_type_map cx state tmap
 
 and gc_pred cx state = function

diff --git a/src/typing/type.ml b/src/typing/type.ml
@@ -871,6 +871,7 @@ module rec TypeTerm : sig
   | Bind of t
   | SpreadType of ObjectSpread.options * t list
   | ValuesType
+  | CallType of t list
   | TypeMap of type_map
   | ReactElementPropsType
   | ReactElementRefType

diff --git a/src/typing/type_annotation.ml b/src/typing/type_annotation.ml
@@ -332,6 +332,14 @@ let rec convert cx tparams_map = Ast.Type.(function
       AbstractT (reason, t)
     )
 
+  | "$Call" ->
+    (match convert_type_params () with
+    | fn::args ->
+       let reason = mk_reason RFunctionCall loc in
+       EvalT (fn, TypeDestructorT (reason, CallType args), mk_id ())
+    | _ ->
+      error_type cx loc (FlowError.ETypeParamMinArity (loc, 1)))
+
   | "$TupleMap" ->
     check_type_param_arity cx loc typeParameters 2 (fun () ->
       let t1, t2 = match convert_type_params () with

diff --git a/src/typing/type_mapper.ml b/src/typing/type_mapper.ml
@@ -341,6 +341,10 @@ class ['a] t = object(self)
           if tlist' == tlist then t
           else SpreadType (options, tlist')
       | ValuesType -> t
+      | CallType args ->
+          let args' = ListUtils.ident_map (self#type_ cx map_cx) args in
+          if args' == args then t
+          else CallType args'
       | TypeMap tmap ->
           let tmap' = self#type_map cx map_cx tmap in
           if tmap' == tmap then t

diff --git a/src/typing/type_visitor.ml b/src/typing/type_visitor.ml
@@ -209,6 +209,7 @@ class ['a] t = object(self)
   | ElementType t -> self#type_ cx acc t
   | Bind t -> self#type_ cx acc t
   | SpreadType (_, ts) -> self#list (self#type_ cx) acc ts
+  | CallType args -> self#list (self#type_ cx) acc args
   | TypeMap (TupleMap t | ObjectMap t | ObjectMapi t) -> self#type_ cx acc t
 
   method private custom_fun_kind cx acc = function

diff --git a/tests/call_type/.flowconfig b/tests/call_type/.flowconfig
diff --git a/tests/call_type/call_type.exp b/tests/call_type/call_type.exp
@@ -0,0 +1,212 @@
+Error: test.js:7
+  7: type A = $Call; // Error: one or more arguments are required.
+              ^^^^^ Incorrect number of type parameters (expected at least 1)
+
+Error: test.js:8
+  8: type B = $Call<>; // Error: one or more arguments are required.
+              ^^^^^^^ Incorrect number of type parameters (expected at least 1)
+
+Error: test.js:13
+ 13: ((null: mixed): C); // Error: mixed ~> number
+             ^^^^^ mixed. This type is incompatible with
+ 13: ((null: mixed): C); // Error: mixed ~> number
+                     ^ number
+
+Error: test.js:15
+ 15: (c: empty); // Error: number ~> empty
+      ^ number. This type is incompatible with
+ 15: (c: empty); // Error: number ~> empty
+         ^^^^^ empty
+
+Error: test.js:19
+ 19: (42: D); // Error: function called with to few arguments.
+      ^^ number. This type is incompatible with
+ 19: (42: D); // Error: function called with to few arguments.
+          ^ undefined (too few arguments, expected default/rest parameters)
+
+Error: test.js:24
+ 24: ((null: mixed): E); // Error: mixed ~> number
+             ^^^^^ mixed. This type is incompatible with
+ 24: ((null: mixed): E); // Error: mixed ~> number
+                     ^ number
+
+Error: test.js:26
+ 26: (e: empty); // Error: number ~> empty
+      ^ number. This type is incompatible with
+ 26: (e: empty); // Error: number ~> empty
+         ^^^^^ empty
+
+Error: test.js:31
+ 31: ((null: mixed): F); // Error: mixed ~> number
+             ^^^^^ mixed. This type is incompatible with
+ 31: ((null: mixed): F); // Error: mixed ~> number
+                     ^ number
+
+Error: test.js:33
+ 33: (f: empty); // Error: number ~> empty
+      ^ number. This type is incompatible with
+ 33: (f: empty); // Error: number ~> empty
+         ^^^^^ empty
+
+Error: test.js:38
+ 38: ((null: mixed): G); // Error: mixed ~> number | string
+             ^^^^^ mixed. This type is incompatible with
+ 38: ((null: mixed): G); // Error: mixed ~> number | string
+                     ^ union: type parameter `A` of function call | type parameter `B` of function call
+  Member 1:
+   35: type G = $Call<Fn2, number, string>;
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^ type parameter `A` of function call
+  Error:
+   38: ((null: mixed): G); // Error: mixed ~> number | string
+               ^^^^^ mixed. This type is incompatible with
+   35: type G = $Call<Fn2, number, string>;
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^ number
+  Member 2:
+   35: type G = $Call<Fn2, number, string>;
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^ type parameter `B` of function call
+  Error:
+   38: ((null: mixed): G); // Error: mixed ~> number | string
+               ^^^^^ mixed. This type is incompatible with
+   35: type G = $Call<Fn2, number, string>;
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^ string
+
+Error: test.js:39
+ 39: (g: number); // Error: number | string ~> number
+      ^ string. This type is incompatible with
+ 39: (g: number); // Error: number | string ~> number
+         ^^^^^^ number
+
+Error: test.js:41
+ 41: (g: empty); // Error: number | string ~> empty
+      ^ number. This type is incompatible with
+ 41: (g: empty); // Error: number | string ~> empty
+         ^^^^^ empty
+
+Error: test.js:41
+ 41: (g: empty); // Error: number | string ~> empty
+      ^ string. This type is incompatible with
+ 41: (g: empty); // Error: number | string ~> empty
+         ^^^^^ empty
+
+Error: union.js:6
+  6: ((null: mixed): A); // Error: mixed ~> number | string
+             ^^^^^ mixed. This type is incompatible with
+  6: ((null: mixed): A); // Error: mixed ~> number | string
+                     ^ union: function call(s)
+  Member 1:
+    3: type A = $Call<(() => number) | (() => string)>;
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ function call
+  Error:
+    6: ((null: mixed): A); // Error: mixed ~> number | string
+               ^^^^^ mixed. This type is incompatible with
+    3: type A = $Call<(() => number) | (() => string)>;
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ number
+  Member 2:
+    3: type A = $Call<(() => number) | (() => string)>;
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ function call
+  Error:
+    6: ((null: mixed): A); // Error: mixed ~> number | string
+               ^^^^^ mixed. This type is incompatible with
+    3: type A = $Call<(() => number) | (() => string)>;
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ string
+
+Error: union.js:7
+  7: (a: number); // Error: number | string ~> number
+      ^ string. This type is incompatible with
+  7: (a: number); // Error: number | string ~> number
+         ^^^^^^ number
+
+Error: union.js:9
+  9: (a: empty); // Error: number | string ~> empty
+      ^ number. This type is incompatible with
+  9: (a: empty); // Error: number | string ~> empty
+         ^^^^^ empty
+
+Error: union.js:9
+  9: (a: empty); // Error: number | string ~> empty
+      ^ string. This type is incompatible with
+  9: (a: empty); // Error: number | string ~> empty
+         ^^^^^ empty
+
+Error: union.js:14
+ 14: ((null: mixed): B); // Error: mixed ~> number | string
+             ^^^^^ mixed. This type is incompatible with
+ 14: ((null: mixed): B); // Error: mixed ~> number | string
+                     ^ union: function call(s)
+  Member 1:
+   11: type B = $Call<(<T>(T) => T) | (<T>(any, T) => T), number, string>;
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ function call
+  Error:
+   14: ((null: mixed): B); // Error: mixed ~> number | string
+               ^^^^^ mixed. This type is incompatible with
+   11: type B = $Call<(<T>(T) => T) | (<T>(any, T) => T), number, string>;
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ number
+  Member 2:
+   11: type B = $Call<(<T>(T) => T) | (<T>(any, T) => T), number, string>;
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ function call
+  Error:
+   14: ((null: mixed): B); // Error: mixed ~> number | string
+               ^^^^^ mixed. This type is incompatible with
+   11: type B = $Call<(<T>(T) => T) | (<T>(any, T) => T), number, string>;
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ string
+
+Error: union.js:15
+ 15: (b: number); // Error: number | string ~> number
+      ^ string. This type is incompatible with
+ 15: (b: number); // Error: number | string ~> number
+         ^^^^^^ number
+
+Error: union.js:17
+ 17: (b: empty); // Error: number | string ~> empty
+      ^ number. This type is incompatible with
+ 17: (b: empty); // Error: number | string ~> empty
+         ^^^^^ empty
+
+Error: union.js:17
+ 17: (b: empty); // Error: number | string ~> empty
+      ^ string. This type is incompatible with
+ 17: (b: empty); // Error: number | string ~> empty
+         ^^^^^ empty
+
+Error: union.js:22
+ 22: ((null: mixed): C); // Error: mixed ~> number | string
+             ^^^^^ mixed. This type is incompatible with
+ 22: ((null: mixed): C); // Error: mixed ~> number | string
+                     ^ union: number | string
+  Member 1:
+   19: type C = $Call<<T>(T) => T, number | string>;
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ number
+  Error:
+   22: ((null: mixed): C); // Error: mixed ~> number | string
+               ^^^^^ mixed. This type is incompatible with
+   19: type C = $Call<<T>(T) => T, number | string>;
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ number
+  Member 2:
+   19: type C = $Call<<T>(T) => T, number | string>;
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ string
+  Error:
+   22: ((null: mixed): C); // Error: mixed ~> number | string
+               ^^^^^ mixed. This type is incompatible with
+   19: type C = $Call<<T>(T) => T, number | string>;
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ string
+
+Error: union.js:23
+ 23: (c: number); // Error: number | string ~> number
+      ^ string. This type is incompatible with
+ 23: (c: number); // Error: number | string ~> number
+         ^^^^^^ number
+
+Error: union.js:25
+ 25: (c: empty); // Error: number | string ~> empty
+      ^ number. This type is incompatible with
+ 25: (c: empty); // Error: number | string ~> empty
+         ^^^^^ empty
+
+Error: union.js:25
+ 25: (c: empty); // Error: number | string ~> empty
+      ^ string. This type is incompatible with
+ 25: (c: empty); // Error: number | string ~> empty
+         ^^^^^ empty
+
+
+Found 25 errors
diff --git a/tests/call_type/test.js b/tests/call_type/test.js
@@ -0,0 +1,41 @@
+// @flow
+
+type Fn0 = () => number;
+type Fn1 = <T>(T) => T;
+type Fn2 = <A, B>(A, B) => A | B;
+
+type A = $Call; // Error: one or more arguments are required.
+type B = $Call<>; // Error: one or more arguments are required.
+
+type C = $Call<Fn0>;
+declare var c: C;
+(42: C); // OK
+((null: mixed): C); // Error: mixed ~> number
+(c: number); // OK
+(c: empty); // Error: number ~> empty
+
+type D = $Call<Fn1>;
+declare var d: D;
+(42: D); // Error: function called with to few arguments.
+
+type E = $Call<Fn1, number>;
+declare var e: E;
+(42: E); // OK
+((null: mixed): E); // Error: mixed ~> number
+(e: number); // OK
+(e: empty); // Error: number ~> empty
+
+type F = $Call<Fn1, number, string>;
+declare var f: F;
+(42: F); // OK
+((null: mixed): F); // Error: mixed ~> number
+(f: number); // OK
+(f: empty); // Error: number ~> empty
+
+type G = $Call<Fn2, number, string>;
+declare var g: G;
+(42: G); // OK
+((null: mixed): G); // Error: mixed ~> number | string
+(g: number); // Error: number | string ~> number
+(g: number | string); // OK
+(g: empty); // Error: number | string ~> empty
diff --git a/tests/call_type/union.js b/tests/call_type/union.js
@@ -0,0 +1,25 @@
+// @flow
+
+type A = $Call<(() => number) | (() => string)>;
+declare var a: A;
+(42: A); // OK
+((null: mixed): A); // Error: mixed ~> number | string
+(a: number); // Error: number | string ~> number
+(a: number | string); // OK
+(a: empty); // Error: number | string ~> empty
+
+type B = $Call<(<T>(T) => T) | (<T>(any, T) => T), number, string>;
+declare var b: B;
+(42: B); // OK
+((null: mixed): B); // Error: mixed ~> number | string
+(b: number); // Error: number | string ~> number
+(b: number | string); // OK
+(b: empty); // Error: number | string ~> empty
+
+type C = $Call<<T>(T) => T, number | string>;
+declare var c: C;
+(42: C); // OK
+((null: mixed): C); // Error: mixed ~> number | string
+(c: number); // Error: number | string ~> number
+(c: number | string); // OK
+(c: empty); // Error: number | string ~> empty