[flow][match] Autocomplete for member patterns in match expressions

Summary:
Autocomplete for match member patterns.

Changelog: [internal]

Reviewed By: panagosg7

Differential Revision: D67830067

fbshipit-source-id: c95916176240364f16e66182710a03fbe3c901c4

src/services/autocomplete/autocomplete_js.ml

@@ -156,6 +156,15 @@ module Inference = struct
     match Statement.statement cx (loc, ClassDeclaration cls) with
     | (_, ClassDeclaration { Flow_ast.Class.id = Some ((_, t), _); _ }) -> t
     | _ -> raise (Internal_exn "typed AST structure mismatch")
+
+  let type_of_identifier cx loc id = Statement.identifier cx id loc
+
+  let type_of_match_member_pattern cx loc mem =
+    Match_pattern.type_of_member_pattern
+      cx
+      ~on_identifier:Statement.identifier
+      ~on_expression:Statement.expression
+      (loc, mem)
 end
 
 class process_request_searcher cx ~from_trigger_character ~cursor =
@@ -939,6 +948,56 @@ class process_request_searcher cx ~from_trigger_character ~cursor =
         this#find loc token Ac_ignored
       else
         key
+
+    method! match_member_pattern member_pattern =
+      let open Ast.MatchPattern.MemberPattern in
+      let (loc, { base; property; _ }) = member_pattern in
+      let base_loc =
+        match base with
+        | BaseIdentifier (loc, _)
+        | BaseMember (loc, _) ->
+          loc
+      in
+      let member_loc = Some (compute_member_loc ~expr_loc:loc ~obj_loc:base_loc) in
+      let obj_type () =
+        match base with
+        | BaseIdentifier (loc, id) -> Inference.type_of_identifier cx loc id
+        | BaseMember (loc, mem) -> Inference.type_of_match_member_pattern cx loc mem
+      in
+      (match property with
+      | PropertyIdentifier (prop_loc, { Ast.Identifier.name; _ }) when this#covers_target prop_loc
+        ->
+        this#find
+          prop_loc
+          name
+          (Ac_member
+             {
+               obj_type = obj_type ();
+               in_optional_chain = false;
+               bracket_syntax = None;
+               member_loc;
+               is_type_annotation = false;
+               is_super = false;
+             }
+          )
+      | PropertyString (prop_loc, { Ast.StringLiteral.raw = token; _ })
+        when this#covers_target prop_loc ->
+        let obj_type = obj_type () in
+        this#find
+          prop_loc
+          token
+          (Ac_member
+             {
+               obj_type;
+               in_optional_chain = false;
+               bracket_syntax = Some (this#default_bracket_syntax obj_type);
+               member_loc;
+               is_type_annotation = false;
+               is_super = false;
+             }
+          )
+      | _ -> ());
+      super#match_member_pattern member_pattern
   end
 
 let autocomplete_id ~cursor _cx _ac_name ac_loc = covers_target cursor ac_loc

src/typing/match_pattern.ml

@@ -223,3 +223,7 @@ and object_properties cx ~on_identifier ~on_expression ~on_binding ~in_or_patter
 
 let pattern cx ~on_identifier ~on_expression ~on_binding acc (loc, p) =
   pattern_ cx ~on_identifier ~on_expression ~on_binding ~in_or_pattern:false acc (loc, p)
+
+let type_of_member_pattern cx ~on_identifier ~on_expression mem =
+  let (_, ((_, t), _)) = member cx ~on_identifier ~on_expression mem in
+  t

src/typing/match_pattern.mli

@@ -17,3 +17,11 @@ val pattern :
   (ALoc.t, ALoc.t) Ast.Expression.t ->
   (ALoc.t, ALoc.t) Ast.MatchPattern.t ->
   (ALoc.t, ALoc.t * Type.t) Ast.MatchPattern.t
+
+val type_of_member_pattern :
+  Context.t ->
+  on_identifier:(Context.t -> ALoc.t Ast.Identifier.t' -> ALoc.t -> Type.t) ->
+  on_expression:
+    (Context.t -> (ALoc.t, ALoc.t) Ast.Expression.t -> (ALoc.t, ALoc.t * Type.t) Ast.Expression.t) ->
+  (ALoc.t, ALoc.t) Ast.MatchPattern.MemberPattern.t ->
+  Type.t

tests/autocomplete_match/autocomplete_match.exp

@@ -45,3 +45,31 @@ pattern-object.js:6:5
 Flags: --pretty
 {"result":[]}
 
+pattern-member.js:6:6
+Flags: --pretty
+{
+  "result":[
+    {"name":"[\"zip-zap\"]","type":"3"},
+    {"name":"bar","type":"{baz: 2}"},
+    {"name":"foo","type":"1"}
+  ]
+}
+
+pattern-member.js:8:7
+Flags: --pretty
+{"result":[{"name":"foo","type":"1"}]}
+
+pattern-member.js:10:11
+Flags: --pretty
+{"result":[{"name":"baz","type":"2"}]}
+
+pattern-member.js:12:6
+Flags: --pretty
+{
+  "result":[
+    {"name":"\"bar\"","type":"{baz: 2}"},
+    {"name":"\"foo\"","type":"1"},
+    {"name":"\"zip-zap\"","type":"3"}
+  ]
+}
+

tests/autocomplete_match/pattern-member.js

@@ -0,0 +1,14 @@
+declare const x: number;
+
+declare const O: {foo: 1, bar: {baz: 2}, 'zip-zap': 3};
+
+const e = match (x) {
+   O. : 0,
+//   ^
+   O.f : 0,
+//    ^
+   O.bar.b : 0,
+//        ^
+   O[ ]: 0,
+//   ^
+};

tests/autocomplete_match/test.sh

@@ -10,3 +10,4 @@ queries_in_file autocomplete "keyword-expression.js" --pretty
 queries_in_file autocomplete "pattern-identifier.js" --pretty
 queries_in_file autocomplete "pattern-binding.js" --pretty
 queries_in_file autocomplete "pattern-object.js" --pretty
+queries_in_file autocomplete "pattern-member.js" --pretty