Allow 'union' and 'default' as bindings in patterns

Author: maxbrunsfeld

corpus/declarations.txt

@@ -519,6 +519,23 @@ let a = if b {
         (block
           (identifier))))))
 
+================================================================================
+Let declarations with contextual keywords as names
+================================================================================
+
+let default = 1;
+let union = 2;
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (let_declaration
+    (identifier)
+    (integer_literal))
+  (let_declaration
+    (identifier)
+    (integer_literal)))
+
 ================================================================================
 Structs
 ================================================================================

grammar.js

@@ -710,7 +710,6 @@ module.exports = grammar({
       field('pattern', choice(
         $._pattern,
         $.self,
-        $._reserved_identifier,
       )),
       ':',
       field('type', $._type)
@@ -1351,6 +1350,7 @@ module.exports = grammar({
       $.tuple_pattern,
       $.tuple_struct_pattern,
       $.struct_pattern,
+      $._reserved_identifier,
       $.ref_pattern,
       $.slice_pattern,
       $.captured_pattern,

src/grammar.json

@@ -4138,10 +4138,6 @@
               {
                 "type": "SYMBOL",
                 "name": "self"
-              },
-              {
-                "type": "SYMBOL",
-                "name": "_reserved_identifier"
               }
             ]
           }
@@ -7959,6 +7955,10 @@
           "type": "SYMBOL",
           "name": "struct_pattern"
         },
+        {
+          "type": "SYMBOL",
+          "name": "_reserved_identifier"
+        },
         {
           "type": "SYMBOL",
           "name": "ref_pattern"