parse turbofishes in patterns

Author: m4rch3n1ng

grammar.js

@@ -1341,6 +1341,7 @@ module.exports = grammar({
       alias(choice(...primitiveTypes), $.identifier),
       $.identifier,
       $.scoped_identifier,
+      $.identifier_with_turbofish,
       $.tuple_pattern,
       $.tuple_struct_pattern,
       $.struct_pattern,
@@ -1358,6 +1359,15 @@ module.exports = grammar({
       '_',
     ),
 
+    identifier_with_turbofish: $ => seq(
+      choice(
+        $.identifier,
+        $.scoped_identifier,
+      ),
+      '::',
+      field('type_arguments', $.type_arguments),
+    ),
+
     tuple_pattern: $ => seq(
       '(',
       sepBy(',', choice($._pattern, $.closure_expression)),

test/corpus/patterns.txt

@@ -520,3 +520,30 @@ fn foo(x: i32) {
             (match_arm
               pattern: (match_pattern)
               value: (block))))))))
+
+================================================================================
+Pattern with turbofish
+================================================================================
+
+match y {
+    None::<T> => 17,
+    _ => 42,
+}
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (expression_statement
+    (match_expression
+      (identifier)
+      (match_block
+        (match_arm
+          (match_pattern
+            (identifier_with_turbofish
+              (identifier)
+              (type_arguments
+                (type_identifier))))
+          (integer_literal))
+        (match_arm
+          (match_pattern)
+          (integer_literal))))))