[flow][match] Error on repeated object keys in object patterns

Summary:
Error on repeated object keys in object patterns.

Changelog: [internal]

Reviewed By: SamChou19815

Differential Revision: D67502325

fbshipit-source-id: f05c9ff2a83f0f55d11199651121bdf2203f3df3

src/typing/debug_js.ml

@@ -1910,6 +1910,8 @@ let dump_error_message =
     | EMatchInvalidUnaryZero { loc } -> spf "EMatchInvalidUnaryZero (%s)" (string_of_aloc loc)
     | EMatchInvalidUnaryPlusBigInt { loc } ->
       spf "EMatchInvalidUnaryBigInt (%s)" (string_of_aloc loc)
+    | EMatchDuplicateObjectProperty { loc; name } ->
+      spf "EMatchDuplicateObjectProperty (%s) (%s)" (string_of_aloc loc) name
     | EDevOnlyRefinedLocInfo { refined_loc; refining_locs = _ } ->
       spf "EDevOnlyRefinedLocInfo {refined_loc=%s}" (string_of_aloc refined_loc)
     | EDevOnlyInvalidatedRefinementInfo { read_loc; invalidation_info = _ } ->

src/typing/errors/error_message.ml

@@ -625,6 +625,10 @@ and 'loc t' =
   | EMatchInvalidObjectPropertyLiteral of { loc: 'loc }
   | EMatchInvalidUnaryZero of { loc: 'loc }
   | EMatchInvalidUnaryPlusBigInt of { loc: 'loc }
+  | EMatchDuplicateObjectProperty of {
+      loc: 'loc;
+      name: string;
+    }
   (* Dev only *)
   | EDevOnlyRefinedLocInfo of {
       refined_loc: 'loc;
@@ -1432,6 +1436,8 @@ let rec map_loc_of_error_message (f : 'a -> 'b) : 'a t' -> 'b t' =
   | EMatchInvalidObjectPropertyLiteral { loc } -> EMatchInvalidObjectPropertyLiteral { loc = f loc }
   | EMatchInvalidUnaryZero { loc } -> EMatchInvalidUnaryZero { loc = f loc }
   | EMatchInvalidUnaryPlusBigInt { loc } -> EMatchInvalidUnaryPlusBigInt { loc = f loc }
+  | EMatchDuplicateObjectProperty { loc; name } ->
+    EMatchDuplicateObjectProperty { loc = f loc; name }
   | EDevOnlyInvalidatedRefinementInfo { read_loc; invalidation_info } ->
     EDevOnlyInvalidatedRefinementInfo
       {
@@ -1733,7 +1739,8 @@ let util_use_op_of_msg nope util = function
   | EMatchInvalidBindingKind _
   | EMatchInvalidObjectPropertyLiteral _
   | EMatchInvalidUnaryZero _
-  | EMatchInvalidUnaryPlusBigInt _ ->
+  | EMatchInvalidUnaryPlusBigInt _
+  | EMatchDuplicateObjectProperty _ ->
     nope
 
 (* Not all messages (i.e. those whose locations are based on use_ops) have locations that can be
@@ -1939,6 +1946,7 @@ let loc_of_msg : 'loc t' -> 'loc option = function
   | EMatchInvalidObjectPropertyLiteral { loc } -> Some loc
   | EMatchInvalidUnaryZero { loc } -> Some loc
   | EMatchInvalidUnaryPlusBigInt { loc } -> Some loc
+  | EMatchDuplicateObjectProperty { loc; _ } -> Some loc
   | EDevOnlyRefinedLocInfo { refined_loc; refining_locs = _ } -> Some refined_loc
   | EDevOnlyInvalidatedRefinementInfo { read_loc; invalidation_info = _ } -> Some read_loc
   | EUnableToSpread _
@@ -2892,6 +2900,8 @@ let friendly_message_of_msg = function
     Normal MessageMatchInvalidObjectPropertyLiteral
   | EMatchInvalidUnaryZero { loc = _ } -> Normal MessageMatchInvalidUnaryZero
   | EMatchInvalidUnaryPlusBigInt { loc = _ } -> Normal MessageMatchInvalidUnaryPlusBigInt
+  | EMatchDuplicateObjectProperty { loc = _; name } ->
+    Normal (MessageMatchDuplicateObjectProperty { name })
 
 let defered_in_speculation = function
   | EUntypedTypeImport _
@@ -3233,3 +3243,4 @@ let error_code_of_message err : error_code option =
   | EMatchInvalidObjectPropertyLiteral _ -> Some MatchInvalidPattern
   | EMatchInvalidUnaryZero _ -> Some MatchInvalidPattern
   | EMatchInvalidUnaryPlusBigInt _ -> Some MatchInvalidPattern
+  | EMatchDuplicateObjectProperty _ -> Some MatchInvalidPattern

src/typing/errors/flow_intermediate_error.ml

@@ -4006,6 +4006,8 @@ let to_printable_error :
       [text "Unary pattern on "; code "0"; text " is not supported."]
     | MessageMatchInvalidUnaryPlusBigInt ->
       [text "Unary pattern "; code "+"; text " on bigint literal is not supported."]
+    | MessageMatchDuplicateObjectProperty { name } ->
+      [text "Duplicate property "; code name; text " in object pattern."]
   in
   let rec convert_error_message { kind; loc; error_code; root; message; misplaced_source_file = _ }
       =

src/typing/errors/flow_intermediate_error_types.ml

@@ -902,6 +902,7 @@ type 'loc message =
   | MessageMatchInvalidObjectPropertyLiteral
   | MessageMatchInvalidUnaryZero
   | MessageMatchInvalidUnaryPlusBigInt
+  | MessageMatchDuplicateObjectProperty of { name: string }
 
 type 'loc intermediate_error = {
   kind: Flow_errors_utils.error_kind;

src/typing/match_pattern.ml

@@ -39,24 +39,25 @@ let object_named_property acc loc name =
 
 let object_property_key cx acc key :
     (ALoc.t, ALoc.t) Flow_ast.Expression.t
-    * (ALoc.t, ALoc.t * Type.t) Ast.MatchPattern.ObjectPattern.Property.key =
+    * (ALoc.t, ALoc.t * Type.t) Ast.MatchPattern.ObjectPattern.Property.key
+    * string =
   let open Ast.MatchPattern.ObjectPattern in
   match key with
   | Property.Identifier (loc, { Ast.Identifier.name; comments }) ->
     let acc = object_named_property acc loc name in
     let current = Unsoundness.at Type.NonBindingPattern loc in
-    (acc, Property.Identifier ((loc, current), { Ast.Identifier.name; comments }))
+    (acc, Property.Identifier ((loc, current), { Ast.Identifier.name; comments }), name)
   | Property.StringLiteral (loc, ({ Ast.StringLiteral.value; _ } as lit)) ->
     let acc = object_named_property acc loc value in
-    (acc, Property.StringLiteral (loc, lit))
+    (acc, Property.StringLiteral (loc, lit), value)
   | Property.NumberLiteral (loc, ({ Ast.NumberLiteral.value; _ } as lit)) ->
+    let prop = Dtoa.ecma_string_of_float value in
     if Js_number.is_float_safe_integer value then
-      let prop = Dtoa.ecma_string_of_float value in
       let acc = object_named_property acc loc prop in
-      (acc, Property.NumberLiteral (loc, lit))
+      (acc, Property.NumberLiteral (loc, lit), prop)
     else (
       Flow_js.add_output cx (Error_message.EMatchInvalidObjectPropertyLiteral { loc });
-      (acc, Property.NumberLiteral (loc, lit))
+      (acc, Property.NumberLiteral (loc, lit), prop)
     )
 
 let binding cx ~on_binding ~kind acc name_loc name =
@@ -195,12 +196,14 @@ and array_elements cx ~on_identifier ~on_expression ~on_binding acc elements =
 
 and object_properties cx ~on_identifier ~on_expression ~on_binding acc props =
   let open Ast.MatchPattern.ObjectPattern in
-  let rec loop acc rev_props = function
+  let rec loop acc seen rev_props = function
     | [] -> List.rev rev_props
     | (loc, { Property.key; pattern = p; shorthand; comments }) :: props ->
-      let (acc, key) = object_property_key cx acc key in
+      let (acc, key, name) = object_property_key cx acc key in
+      if SSet.mem name seen then
+        Flow_js.add_output cx (Error_message.EMatchDuplicateObjectProperty { loc; name });
       let p = pattern cx ~on_identifier ~on_expression ~on_binding acc p in
       let prop = (loc, { Property.key; pattern = p; shorthand; comments }) in
-      loop acc (prop :: rev_props) props
+      loop acc (SSet.add name seen) (prop :: rev_props) props
   in
-  loop acc [] props
+  loop acc SSet.empty [] props

tests/match/match.exp

@@ -510,6 +510,30 @@ Unary pattern `+` on bigint literal is not supported. [match-invalid-pattern]
            ^^^
 
 
+Error ------------------------------------------------------------------------------------------ pattern-errors.js:56:17
+
+Duplicate property `foo` in object pattern. [match-invalid-pattern]
+
+   56|     {foo: true, foo: false}: 0, // ERROR
+                       ^^^
+
+
+Error ------------------------------------------------------------------------------------------ pattern-errors.js:61:17
+
+Duplicate property `foo` in object pattern. [match-invalid-pattern]
+
+   61|     {const foo, foo: true}: 0, // ERROR
+                       ^^^
+
+
+Error ------------------------------------------------------------------------------------------ pattern-errors.js:66:17
+
+Duplicate property `foo` in object pattern. [match-invalid-pattern]
+
+   66|     {foo: true, 'foo': false}: 0, // ERROR
+                       ^^^^^
+
+
 Error -------------------------------------------------------------------------------------------------- patterns.js:9:3
 
 Cannot cast `out` to empty because number [1] is incompatible with empty [2]. [incompatible-cast]
@@ -635,4 +659,4 @@ References:
 
 
 
-Found 48 errors
+Found 51 errors

tests/match/pattern-errors.js

@@ -47,3 +47,23 @@
     1n: true, // OK
   };
 }
+
+// Duplicate object keys banned
+{
+  declare const x: {foo: boolean};
+
+  const e1 = match (x) {
+    {foo: true, foo: false}: 0, // ERROR
+    _: 0,
+  };
+
+  const e2 = match (x) {
+    {const foo, foo: true}: 0, // ERROR
+    _: 0,
+  };
+
+  const e3 = match (x) {
+    {foo: true, 'foo': false}: 0, // ERROR
+    _: 0,
+  };
+}